JP4288409B2 - Zoom lens - Google Patents

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JP4288409B2
JP4288409B2 JP2003051386A JP2003051386A JP4288409B2 JP 4288409 B2 JP4288409 B2 JP 4288409B2 JP 2003051386 A JP2003051386 A JP 2003051386A JP 2003051386 A JP2003051386 A JP 2003051386A JP 4288409 B2 JP4288409 B2 JP 4288409B2
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lens
auxiliary
zoom
curvature
radius
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JP2004258509A (en
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基之 大竹
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株式会社ニコン
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    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS, OR APPARATUS
    • G02B15/00Optical objectives with means for varying the magnification
    • G02B15/14Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective
    • G02B15/16Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective with interdependent non-linearly related movements between one lens or lens group, and another lens or lens group
    • G02B15/163Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective with interdependent non-linearly related movements between one lens or lens group, and another lens or lens group having a first movable lens or lens group and a second movable lens or lens group, both in front of a fixed lens or lens group
    • G02B15/167Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective with interdependent non-linearly related movements between one lens or lens group, and another lens or lens group having a first movable lens or lens group and a second movable lens or lens group, both in front of a fixed lens or lens group having an additional fixed front lens or group of lenses
    • G02B15/173Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective with interdependent non-linearly related movements between one lens or lens group, and another lens or lens group having a first movable lens or lens group and a second movable lens or lens group, both in front of a fixed lens or lens group having an additional fixed front lens or group of lenses arranged +-+
    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS, OR APPARATUS
    • G02B15/00Optical objectives with means for varying the magnification
    • G02B15/14Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective
    • G02B15/144Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective having four groups only
    • G02B15/1441Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective having four groups only the first group being positive
    • G02B15/144113Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective having four groups only the first group being positive arranged +-++
    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS, OR APPARATUS
    • G02B27/00Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/64Imaging systems using optical elements for stabilisation of the lateral and angular position of the image
    • G02B27/646Imaging systems using optical elements for stabilisation of the lateral and angular position of the image compensating for small deviations, e.g. due to vibration or shake

Description

【0001】
【発明の属する技術分野】
本発明はズームレンズに関し、特にレンズ系を構成する一部のレンズを光軸に対して略垂直な方向へ移動させることによって像を移動させた際に生じる諸収差の変化が少ない高変倍比のズームレンズに関する。
【0002】
【従来の技術】
従来、レンズ系を構成する一部のレンズを光軸に対して略垂直な方向へ移動(シフト)させることによって像を移動(シフト)させることが可能な、いわゆる像シフト可能な光学系が知られている。 Conventionally, a so-called image-shiftable optical system is known in which an image can be moved (shifted) by moving (shifting) some of the lenses constituting the lens system in a direction substantially perpendicular to the optical axis. Has been done. 斯かる光学系として、ズームレンズ中に配置されている一部のレンズを光軸に対して略垂直な方向へシフトさせることによって像をシフトさせることを可能としたズームレンズが提案されている(例えば、特許文献1参照)。 As such an optical system, a zoom lens capable of shifting an image by shifting a part of the lenses arranged in the zoom lens in a direction substantially perpendicular to the optical axis has been proposed (). For example, see Patent Document 1).
以下、本明細書において、光軸に対して略垂直な方向へシフトさせるレンズをシフトレンズ群という。 Hereinafter, in the present specification, a lens that shifts in a direction substantially perpendicular to the optical axis is referred to as a shift lens group.
【0003】 0003
また近年、写真用レンズとしてズームレンズが一般的に用いられている。 In recent years, a zoom lens has been generally used as a photographic lens. 写真用レンズとしてズームレンズを用いる場合、被写体に近づいた撮影を行うことが可能となるため、撮影者の意図に合わせた撮影を行うことができるというユーザーメリットがある。 When a zoom lens is used as a photographic lens, it is possible to take a picture close to the subject, so that there is a user merit that the picture can be taken according to the photographer's intention. このため、写真用レンズとしてのズームレンズの一般化に伴い、被写体により近づいた撮影を可能とする高変倍比のズームレンズが市場に提供されている。 For this reason, with the generalization of zoom lenses as photographic lenses, zoom lenses with high magnification ratios that enable shooting closer to the subject are being offered on the market.
被写体により近づいた撮影が可能な高変倍比のズームレンズとして、正負正正4群タイプのズームレンズが知られている(例えば、特許文献2参照)。 As a zoom lens with a high magnification ratio that enables shooting closer to the subject, a positive / negative / positive 4-group type zoom lens is known (see, for example, Patent Document 2).
正負正正4群タイプのズームレンズは、物体側より順に、正の屈折力を有する第1レンズ群と、負の屈折力を有する第2レンズ群と、正の屈折力を有する第3レンズ群と、正の屈折力を有する第4レンズ群との4つのレンズ群からなる。 The positive / negative positive / positive 4-group type zoom lenses are, in order from the object side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, and a third lens group having a positive refractive power. And a fourth lens group having a positive refractive power. そしてこのズームレンズは、広角端状態(焦点距離が最も短い)から望遠端状態(焦点距離が最も長い)までレンズ位置状態が変化する際に、第1レンズ群と第2レンズ群との間隔が増大し、第2レンズ群と第3レンズ群との間隔が減少し、第3レンズ群と第4レンズ群との間隔が減少するように、少なくとも第1レンズ群及び第4レンズ群が物体側へ移動する構成である。 In this zoom lens, when the lens position changes from the wide-angle end state (the shortest focal length) to the telescopic end state (the longest focal length), the distance between the first lens group and the second lens group is increased. At least the first lens group and the fourth lens group are on the object side so that the distance between the second lens group and the third lens group decreases and the distance between the third lens group and the fourth lens group decreases. It is a configuration that moves to.
【0004】 0004
また、写真用レンズとしてのズームレンズのさらなる一般化に伴い、携帯性の向上というユーザーニーズに応えるために、小型化や軽量化を図ったズームレンズが提案されている。 In addition, with the further generalization of zoom lenses as photographic lenses, miniaturized and lightweight zoom lenses have been proposed in order to meet the needs of users for improving portability.
一方、特に小型化や軽量化を図ったズームレンズでは、例えば撮影者がレリーズボタンを押す際に生じるカメラのブレのような、撮影の際に生じるカメラの微小なブレによって、露出中に像がブレてしまう。 On the other hand, especially with a zoom lens that has been made smaller and lighter, an image appears during exposure due to minute camera shake that occurs during shooting, such as camera shake that occurs when the photographer presses the release button. It shakes. また、カメラのブレ量を一定とした場合、焦点距離の増長に従って像のブレ量が増大するため、カメラの微小なブレによっても画像が著しく劣化してしまう。 Further, when the amount of blurring of the camera is constant, the amount of blurring of the image increases as the focal length increases, so that the image is significantly deteriorated even by a slight blurring of the camera.
そこで、ズームレンズを像シフト可能なズームレンズとして該ズームレンズに駆動系と検出系と制御系とを組み合わせることによって、上述のカメラのブレに起因する画像のブレを補正する方法が知られている(例えば、特許文献3参照)。 Therefore, a method is known in which a zoom lens is used as a zoom lens capable of image shift, and a drive system, a detection system, and a control system are combined with the zoom lens to correct image blur caused by the camera blur described above. (See, for example, Patent Document 3). 斯かるズームレンズにおいてまず検出系は、カメラのブレを検出する。 In such a zoom lens, the detection system first detects camera shake. そして制御系は、検出系よって検出されたブレを補正するため、駆動系に駆動量を与えてシフトレンズ群を制御する。 Then, the control system controls the shift lens group by giving a drive amount to the drive system in order to correct the blur detected by the detection system. そして駆動系は、シフトレンズ群を光軸に対して略垂直な方向へ駆動させ、カメラのブレに起因する画像のブレを補正する。 Then, the drive system drives the shift lens group in a direction substantially perpendicular to the optical axis, and corrects the blurring of the image caused by the blurring of the camera.
【0005】 0005
【特許文献1】 [Patent Document 1]
特開平2−81020号公報【特許文献2】 Japanese Unexamined Patent Publication No. 2-81020 [Patent Document 2]
特開平11−142739号公報【特許文献3】 Japanese Unexamined Patent Publication No. 11-142739 [Patent Document 3]
特開平10−282413号公報【0006】 Japanese Unexamined Patent Publication No. 10-282413
【発明が解決しようとする課題】 [Problems to be Solved by the Invention]
一般にズームレンズでは、ズームレンズ全体として所定の光学性能を得るため、レンズ群毎に諸収差を補正することが必要である。 Generally, in a zoom lens, it is necessary to correct various aberrations for each lens group in order to obtain a predetermined optical performance of the zoom lens as a whole. また、各レンズ群に対して求められる収差を補正した状態(収差補正状態)はある程度の範囲を有しており、一般に変倍比が大きくなるほどその範囲は小さくなる。 Further, the state in which the aberration required for each lens group is corrected (aberration correction state) has a certain range, and generally, the larger the magnification ratio, the smaller the range.
一方、像シフト可能な光学系では、像をシフトさせた際に発生する諸収差の変動を抑えるため、シフトレンズ群単独に対して求められる収差補正状態がある。 On the other hand, in an optical system capable of image shift, there is an aberration correction state required for the shift lens group alone in order to suppress fluctuations in various aberrations generated when the image is shifted.
従って、変倍比を大きくした際に良好な光学性能を得るためシフトレンズ群に対して求められる収差補正状態と、像をシフトさせた際に発生する諸収差の変動を良好に補正するためシフトレンズ群に対して求められる収差補正状態とには隔たりがある。 Therefore, the aberration correction state required for the shift lens group in order to obtain good optical performance when the magnification ratio is increased, and the shift in order to satisfactorily correct the fluctuation of various aberrations generated when the image is shifted. There is a gap from the aberration correction state required for the lens group. このため、高変倍比化を図ることと、像シフト可能な光学系を構成することとの両立は非常に困難であるという問題がある。 For this reason, there is a problem that it is very difficult to achieve both a high magnification ratio and a structure of an optical system capable of image shift.
【0007】 0007
上記特許文献3に開示のズームレンズは、ズームレンズを構成するレンズ群の数が多い。 The zoom lens disclosed in Patent Document 3 has a large number of lens groups constituting the zoom lens. 従って、広角端状態から望遠端状態までレンズ位置状態が変化する際の各レンズ群のズーム軌道について選択の自由度が大きい。 Therefore, there is a large degree of freedom in selecting the zoom trajectory of each lens group when the lens position state changes from the wide-angle end state to the telephoto end state. このため、高い光学性能を得ることができる。 Therefore, high optical performance can be obtained. しかしながら、レンズ群を移動させるための駆動機構の複雑化を招くことや、製造時にレンズ群同士の相互偏芯が発生する要因が増えることから、安定した光学品質を維持することが困難であるという問題がある。 However, it is difficult to maintain stable optical quality because the drive mechanism for moving the lens group becomes complicated and the factors that cause mutual eccentricity between the lens groups increase during manufacturing. There's a problem.
【0008】 0008
そこで本発明は上記問題点に鑑みてなされたものであり、レンズ系を構成する一部のレンズを光軸に対して略垂直な方向へ移動させることによって像を移動させることが可能な高変倍比のズームレンズを提供することを目的とする。 Therefore, the present invention has been made in view of the above problems, and the image can be moved by moving some of the lenses constituting the lens system in a direction substantially perpendicular to the optical axis. It is an object of the present invention to provide a zoom lens having a magnification ratio.
【0009】 0009
【課題を解決するための手段】 [Means for solving problems]
上記課題を解決するために本発明は、 In order to solve the above problems, the present invention
物体側より順に、正の屈折力を有する第1レンズ群と、負の屈折力を有する第2レンズ群と、正の屈折力を有する第3レンズ群と、正の屈折力を有する第4レンズ群とからなり From the object side, the first lens group having a positive refractive power, the second lens group having a negative refractive power, the third lens group having a positive refractive power, and the fourth lens having a positive refractive power. It consists of a group,
前記第3レンズ群内部又は前記第3レンズ群近傍に、前記第3レンズ群と共に光軸に沿って移動する開口絞りが配置されており、 An aperture diaphragm that moves along the optical axis together with the third lens group is arranged inside the third lens group or in the vicinity of the third lens group.
広角端状態から望遠端状態への変倍の際に、前記第1レンズ群と前記第2レンズ群との間隔が増大し、前記第2レンズ群と前記第3レンズ群との間隔が減少し、前記第3レンズ群と前記第4レンズ群との間隔が減少するように、少なくとも前記第1レンズ群及び前記第4レンズ群が物体側へ移動し、 When scaling from the wide-angle end state to the telescopic end state , the distance between the first lens group and the second lens group increases, and the distance between the second lens group and the third lens group decreases. At least the first lens group and the fourth lens group move toward the object so that the distance between the third lens group and the fourth lens group is reduced.
前記第3レンズ群は、第1補助レンズ群と、第2補助レンズ群と、第3補助レンズ群とからなり、前記第2補助レンズ群は前記第1補助レンズ群の像側に空気間隔を隔てて配置されており、前記第3補助レンズ群は前記第2補助レンズ群の像側に空気間隔を隔てて配置されており、 The third lens group includes a first auxiliary lens group, a second auxiliary lens group, and a third auxiliary lens group, the second auxiliary lens group air space on an image side of the first auxiliary lens group The third auxiliary lens group is arranged at a distance, and the third auxiliary lens group is arranged at an air interval on the image side of the second auxiliary lens group.
前記第2補助レンズ群を前記光軸に対して略垂直な方向へ移動させることによって、像を移動させることが可能であり By moving to a direction substantially perpendicular to the optical axis of the second auxiliary lens group, it is possible to move the image,
以下の条件式を満足することを特徴とするズームレンズ。 A zoom lens characterized by satisfying the following conditional expression.
0.05<Ds/fw<0.7 0.05 <Ds / fw <0.7
0.1<ft/fA<1.5 0.1 <ft / fA <1.5
但し、 However,
Ds:前記開口絞りから、前記第2補助レンズ群のレンズ面のうちの前記開口絞りに最も近いレンズ面までの光軸に沿った距離, Ds: The distance along the optical axis from the aperture diaphragm to the lens surface of the lens surface of the second auxiliary lens group closest to the aperture diaphragm.
fw:広角端状態における前記ズームレンズ全体の焦点距離, fw: Focal length of the entire zoom lens in the wide-angle end state,
fA:望遠端状態における前記第2補助レンズ群よりも物体側に位置する全てのレンズによる焦点距離, fA: Focal length of all lenses located closer to the object than the second auxiliary lens group in the telephoto end state,
ft:望遠端状態における前記ズームレンズ全体の焦点距離. ft: Focal length of the entire zoom lens in the telephoto end state.
【0010】 0010
本発明によるズームレンズは、従来の正負正正4群タイプのズームレンズと同様、物体側より順に、正の屈折力を有する第1レンズ群と、負の屈折力を有する第2レンズ群と、正の屈折力を有する第3レンズ群と、正の屈折力を有する第4レンズ群とを有する。 The zoom lens according to the present invention includes a first lens group having a positive refractive power, a second lens group having a negative refractive power, and a second lens group having a negative refractive power in order from the object side, like the conventional positive / negative positive four-group type zoom lens. It has a third lens group having a positive refractive power and a fourth lens group having a positive refractive power. そして、広角端状態から望遠端状態までレンズ位置状態が変化する際に、第1レンズ群と第2レンズ群との間隔が増大し、第2レンズ群と第3レンズ群との間隔が減少し、第3レンズ群と第4レンズ群との間隔が減少するように、少なくとも第1レンズ群及び第4レンズ群が物体側へ移動する。 Then, when the lens position state changes from the wide-angle end state to the telescopic end state, the distance between the first lens group and the second lens group increases, and the distance between the second lens group and the third lens group decreases. , At least the first lens group and the fourth lens group move toward the object so that the distance between the third lens group and the fourth lens group is reduced.
高変倍比のズームレンズでは、レンズ位置状態の変化に伴う軸外収差の変動を良好に補正するため、開口絞りをレンズ系の中心付近に配置することが望ましい。 In a zoom lens with a high magnification ratio, it is desirable to arrange the aperture diaphragm near the center of the lens system in order to satisfactorily correct the fluctuation of off-axis aberration due to the change in the lens position state. 従って、本発明によるズームレンズでは、開口絞りを第3レンズ群近傍または第3レンズ群内部に配置している。 Therefore, in the zoom lens according to the present invention, the aperture diaphragm is arranged near the third lens group or inside the third lens group .
【0011】 0011
上記レンズ構成の下、本発明によるズームレンズは以下の条件(A),(B),(C)を満足する構成とすることによって、像シフト時に発生する諸収差の変動を良好に補正することができる。 Under the above lens configuration, the zoom lens according to the present invention has a configuration that satisfies the following conditions (A), (B), and (C), thereby satisfactorily correcting fluctuations in various aberrations that occur during image shifting. Can be done.
(A)第3レンズ群を物体側から順に第1補助レンズ群と第2補助レンズ群と第3補助レンズ群との3つの補助レンズ群で構成し、第2補助レンズ群を光軸に対して略垂直な方向へシフトさせることによって像シフトを行う(第2補助レンズ群をシフトレンズ群とする)。 (A) The third lens group is composed of three auxiliary lens groups, that is, a first auxiliary lens group, a second auxiliary lens group, and a third auxiliary lens group in order from the object side, and the second auxiliary lens group is arranged with respect to the optical axis. The image is shifted by shifting in a substantially vertical direction (the second auxiliary lens group is referred to as a shift lens group).
(B)第2補助レンズ群と開口絞りとの距離を適切に設定する。 (B) Set the distance between the second auxiliary lens group and the aperture stop appropriately.
(C)第2補助レンズ群よりも物体側に位置する全てのレンズによる焦点距離を適切に設定する。 (C) The focal lengths of all lenses located closer to the object than the second auxiliary lens group are appropriately set.
【0012】 [0012]
条件(A)は、レンズ位置状態の変化に伴う諸収差の変動と像シフト時に発生する諸収差の変動とを良好に補正するための条件である。 The condition (A) is a condition for satisfactorily correcting the fluctuation of various aberrations due to the change of the lens position state and the fluctuation of various aberrations generated at the time of image shift.
本発明によるズームレンズは、第3レンズ群全体がレンズ位置状態の変化に伴う諸収差の変動を良好に補正し、第2補助レンズ群(シフトレンズ群)が像シフト時に発生する諸収差の変動を良好に補正するように、収差補正上の機能を分ける構成としている。 In the zoom lens according to the present invention, the entire third lens group satisfactorily corrects fluctuations in various aberrations due to changes in the lens position state, and the second auxiliary lens group (shift lens group) satisfactorily corrects fluctuations in various aberrations that occur during image shifting. The function for aberration correction is divided so as to satisfactorily correct. これにより、レンズ位置状態の変化に伴う諸収差の変動を良好に補正し、これと同時に像シフト時に発生する諸収差の変動を良好に補正することができる。 As a result, fluctuations in various aberrations due to changes in the lens position state can be satisfactorily corrected, and at the same time, fluctuations in various aberrations that occur during image shifting can be satisfactorily corrected.
【0013】 0013
条件(B)は、像シフト時に発生する軸外収差の変動を良好に補正するための条件である。 Condition (B) is a condition for satisfactorily correcting fluctuations in off-axis aberrations that occur during image shifting.
一般に、開口絞りの近くに配置されたレンズ群に入射する軸外光束は、該レンズ群の中央付近を通過する。 Generally, the off-axis luminous flux incident on a lens group arranged near the aperture diaphragm passes near the center of the lens group. これに対し、開口絞りから離れて配置されたレンズ群に入射する軸外光束は、光軸から離れて該レンズ群を通過する。 On the other hand, the off-axis luminous flux incident on the lens group arranged away from the aperture diaphragm passes through the lens group away from the optical axis.
また、各レンズのレンズ面の形状は、光軸を回転中心とした円形状である。 The shape of the lens surface of each lens is a circular shape centered on the optical axis. このため、シフトレンズ群を光軸に対して略垂直な方向へシフトさせると、シフトさせた方向での屈折力と該方向と反対の方向での屈折力とが逆向きに変化する。 Therefore, when the shift lens group is shifted in a direction substantially perpendicular to the optical axis, the refractive power in the shifted direction and the refractive power in the direction opposite to the shifted direction change in opposite directions. 即ち、シフトレンズ群のレンズ面のうち、シフトさせた方向側のレンズ面に入射した光は光軸に近づくようにより屈折され、シフトさせた方向と反対側のレンズ面に入射した光は光軸から遠ざかるようにより屈折される。 That is, among the lens surfaces of the shift lens group, the light incident on the lens surface on the shifted direction side is refracted so as to approach the optical axis, and the light incident on the lens surface on the opposite side to the shifted direction is the optical axis. It is refracted by moving away from. このため、軸外収差の変動が起こりやすくなる。 Therefore, fluctuations in off-axis aberrations are likely to occur.
【0014】 0014.
条件(C)は、像シフト時に発生する軸上収差の変動を良好に補正するための条件である。 The condition (C) is a condition for satisfactorily correcting the fluctuation of the axial aberration generated at the time of image shifting.
第2補助レンズ群に入射する軸外光束が平行な状態に近い場合、光軸に平行な状態でレンズ系に入射する光束は、第2補助レンズ群のシフトに併せてその像位置がシフトするが、収差の変動は少ない。 When the off-axis luminous flux incident on the second auxiliary lens group is close to the parallel state, the image position of the luminous flux incident on the lens system in the state parallel to the optical axis shifts in accordance with the shift of the second auxiliary lens group. However, the fluctuation of aberration is small.
また、第2補助レンズ群よりも物体側に位置する全てのレンズによる焦点距離が負となる場合、第2補助レンズ群に軸上光束が広がって入射するため、球面収差の補正を十分に行うことができない。 Further, when the focal lengths of all the lenses located on the object side of the second auxiliary lens group are negative, the axial light beam spreads and is incident on the second auxiliary lens group, so that the spherical aberration is sufficiently corrected. I can't.
従って、第2補助レンズ群よりも物体側に位置する全てのレンズが全体として正の屈折力を有し、さらにこの正の屈折力があまり大きくない時に、軸上収差の変動を良好に補正することができる。 Therefore, when all the lenses located on the object side of the second auxiliary lens group have a positive refractive power as a whole and the positive refractive power is not so large, the fluctuation of the axial aberration is satisfactorily corrected. be able to.
【0015】 0015.
次に、各条件式について詳細に説明する。 Next, each conditional expression will be described in detail.
以下の条件式(1)は、上記条件(B)を具体的に数値規定する条件式であり、広角端状態における開口絞りから第3レンズ群中に配置された第2補助レンズ群までの間隔を規定する条件式である。 The following conditional expression (1) is a conditional expression that specifically numerically defines the above condition (B), and is an interval from the aperture diaphragm in the wide-angle end state to the second auxiliary lens group arranged in the third lens group. It is a conditional expression that defines.
(1)0.05<Ds/fw<0.7 (1) 0.05 <Ds / fw <0.7
但し、 However,
Ds:開口絞りから、第2補助レンズ群のレンズ面のうちの開口絞りに最も近いレンズ面までの光軸に沿った距離, Ds: The distance along the optical axis from the aperture stop to the lens surface of the second auxiliary lens group that is closest to the aperture stop.
fw:広角端状態におけるズームレンズ全体の焦点距離. fw: Focal length of the entire zoom lens in the wide-angle end state.
【0016】 0016.
条件式(1)の上限値を上回ると、広角端状態においてシフトレンズ群に入射する軸外光束が光軸から大きく離れてしまう。 If the upper limit of the conditional expression (1) is exceeded, the off-axis luminous flux incident on the shift lens group in the wide-angle end state is greatly deviated from the optical axis. このため、像シフト時に発生する軸外収差の変動を良好に補正することができなくなってしまう。 For this reason, it becomes impossible to satisfactorily correct fluctuations in off-axis aberrations that occur during image shifting.
一方、条件式(1)の下限値を下回ると、シフトレンズ群と開口絞りとの間に十分なスペースを設けることができず、小絞り時(開口を小さく絞った時)に絞り羽根とシフトレンズ群との干渉が起こってしまう。 On the other hand, if it falls below the lower limit of the conditional expression (1), a sufficient space cannot be provided between the shift lens group and the aperture diaphragm, and the diaphragm blade and the shift are made when the aperture is small (when the aperture is narrowed down). Interference with the lens group will occur. あるいは、各部品の公差によって、製造時にシフトレンズ群が絞り部材に触れてしまうという恐れが生じてしまう。 Alternatively, due to the tolerance of each component, there is a risk that the shift lens group may touch the diaphragm member during manufacturing.
【0017】 [0017]
条件式(2)は、上記条件(C)を具体的に数値規定する条件式である。 The conditional expression (2) is a conditional expression that specifically numerically defines the above condition (C).
(2)0.1<ft/fA<1.5 (2) 0.1 <ft / fA <1.5
但し、 However,
fA:望遠端状態における第2補助レンズ群よりも物体側に位置する全てのレンズによる焦点距離, fA: Focal length of all lenses located closer to the object than the second auxiliary lens group in the telephoto end state,
ft:望遠端状態におけるズームレンズ全体の焦点距離. ft: Focal length of the entire zoom lens in the telephoto end state.
【0018】 0018
条件式(2)の上限値を上回ると、軸上光束が大きく収斂されて第2補助レンズ群に入射する。 When the upper limit of the conditional expression (2) is exceeded, the axial luminous flux is largely converged and is incident on the second auxiliary lens group. このため、像シフト時に発生する軸上収差の変動が非常に大きくなってしまう。 Therefore, the fluctuation of the axial aberration generated at the time of image shift becomes very large.
一方、条件式(2)の下限値を下回ると、軸上光束が広がって第2補助レンズ群に入射する。 On the other hand, when the value falls below the lower limit of the conditional expression (2), the axial luminous flux spreads and is incident on the second auxiliary lens group. このため、軸上収差の補正を十分に行うことができなくなってしまう。 Therefore, it becomes impossible to sufficiently correct the axial aberration.
尚、第2補助レンズ群のレンズ径は、該第2補助レンズ群を光軸に対して略垂直な方向へシフトさせるための駆動系の大きさに直接結び付くものである。 The lens diameter of the second auxiliary lens group is directly linked to the size of the drive system for shifting the second auxiliary lens group in a direction substantially perpendicular to the optical axis. 従って、第2補助レンズ群のレンズ径を小型化して携帯性の向上を図るためには、条件式(2)の下限値を0.15とすることが望ましい。 Therefore, in order to reduce the lens diameter of the second auxiliary lens group and improve portability, it is desirable to set the lower limit value of the conditional expression (2) to 0.15.
【0019】 0019
上記構成の下、本発明によるズームレンズは、第3レンズ群を構成する各補助レンズ群が以下の条件(D),(E),(F)を満足する構成とすることによって、レンズ径の小型化を図ることと像シフト時に発生する諸収差の変動をより良好に補正することができる。 Under the above configuration, the zoom lens according to the present invention has a lens diameter such that each auxiliary lens group constituting the third lens group satisfies the following conditions (D), (E), and (F). It is possible to reduce the size and better correct fluctuations in various aberrations that occur during image shifting.
(D)第1補助レンズ群の屈折力を正とし、その焦点距離を適切に設定する。 (D) The refractive power of the first auxiliary lens group is set to positive, and the focal length thereof is set appropriately.
(E)第2補助レンズ群の屈折力を正とし、その形状を適切に設定する。 (E) Set the refractive power of the second auxiliary lens group to positive, and set the shape appropriately.
(F)第3補助レンズ群の屈折力を負とする。 (F) The refractive power of the third auxiliary lens group is negative.
【0020】 0020
条件(D)は、望遠端状態において、小型化を図り、画面中心部でより良好に収差の補正を行うための条件である。 Condition (D) is a condition for reducing the size and correcting aberrations better at the center of the screen in the telephoto end state.
本発明によるズームレンズは、従来の正負正正4群タイプのズームレンズと同様、第1レンズ群と第2レンズ群との合成屈折力が負である。 The zoom lens according to the present invention has a negative combined refractive power between the first lens group and the second lens group, similar to the conventional positive / negative / positive four-group type zoom lens. 従って、上記条件(C)を満足するために本発明によるズームレンズは、第2レンズ群と第2補助レンズ群との間に位置する第1補助レンズ群が正の屈折力を有する構成とする。 Therefore, in order to satisfy the above condition (C), the zoom lens according to the present invention has a configuration in which the first auxiliary lens group located between the second lens group and the second auxiliary lens group has a positive refractive power. ..
ここで、小型化を図るためには第1補助レンズ群の屈折力を大きくすることが有効である。 Here, in order to reduce the size, it is effective to increase the refractive power of the first auxiliary lens group. しかし、第1補助レンズ群の屈折力を大きくし過ぎると望遠端状態において負の球面収差の補正を十分に行うことができなくなってしまう。 However, if the refractive power of the first auxiliary lens group is made too large, it becomes impossible to sufficiently correct the negative spherical aberration in the telephoto end state.
【0021】 0021.
従って本発明によるズームレンズは、以下の条件式(3)を満足することが望ましい。 Therefore, it is desirable that the zoom lens according to the present invention satisfies the following conditional expression (3).
(3)0.06<fa/ft<0.2 (3) 0.06 <fa / ft <0.2
但し、 However,
fa:第1補助レンズ群の焦点距離, fa: Focal length of the first auxiliary lens group,
ft:望遠端状態におけるズームレンズ全体の焦点距離. ft: Focal length of the entire zoom lens in the telephoto end state.
【0022】 0022.
条件式(3)は、第1補助レンズ群の焦点距離を規定する条件式である。 The conditional expression (3) is a conditional expression that defines the focal length of the first auxiliary lens group.
条件式(3)の上限値を上回ると、望遠端状態におけるズームレンズの全長が大型化してしまう。 If the upper limit of the conditional expression (3) is exceeded, the total length of the zoom lens in the telephoto end state becomes large.
一方、条件式(3)の下限値を下回ると、望遠端状態において発生する負の球面収差を良好に補正することができなくなってしまう。 On the other hand, if it falls below the lower limit of the conditional expression (3), the negative spherical aberration generated in the telephoto end state cannot be satisfactorily corrected.
【0023】 [0023]
条件(E)は、像シフト時にシフトレンズ群単独によって画面中心部において発生する偏芯コマ収差の良好な補正を行うための条件である。 The condition (E) is a condition for satisfactorily correcting the eccentric coma aberration generated in the center of the screen by the shift lens group alone at the time of image shifting.
一般にシフトレンズ群は、正の屈折力を有していても、負の屈折力を有していても像シフトを行うことが可能である。 In general, a shift lens group can perform image shifting regardless of whether it has a positive refractive power or a negative refractive power. 本発明によるズームレンズでは、広角端状態における画角が大きいため、シフトレンズ群が負の屈折力を有する場合、光束を発散させてしまう。 In the zoom lens according to the present invention, since the angle of view at the wide-angle end state is large, the luminous flux is diverged when the shift lens group has a negative refractive power. このため、レンズ径の大型化を招いてしてしまうだけでなく、画面周辺部に向かう軸外光束がレンズの周縁部を通過することからコマ収差が多大に発生してしまう。 For this reason, not only the lens diameter is increased, but also the off-axis luminous flux toward the peripheral portion of the screen passes through the peripheral portion of the lens, which causes a large amount of coma aberration. 従って本発明によるズームレンズでは、シフトレンズ群である第2補助レンズ群が正の屈折力を有する構成としている。 Therefore, in the zoom lens according to the present invention, the second auxiliary lens group, which is a shift lens group, has a positive refractive power.
また、像シフト時にシフトレンズ群単独によって画面中心部において発生する偏芯コマ収差を良好に補正するために、シフトレンズ群の形状を適切に設定することが望ましい。 Further, it is desirable to appropriately set the shape of the shift lens group in order to satisfactorily correct the eccentric coma aberration generated in the center of the screen by the shift lens group alone at the time of image shifting. このためにはシフトレンズ群単独で発生する球面収差を良好に補正することに加え、正弦条件を満足する構成とすることが必要である。 For this purpose, in addition to satisfactorily correcting the spherical aberration generated by the shift lens group alone, it is necessary to have a configuration that satisfies the sine condition.
【0024】 0024
従って本発明によるズームレンズは、第2補助レンズ群が1枚の正レンズと1枚の負レンズとを少なくとも有し、以下の条件式(4)を満足することが望ましい。 Therefore, in the zoom lens according to the present invention, it is desirable that the second auxiliary lens group has at least one positive lens and one negative lens, and satisfies the following conditional expression (4).
(4)−0.6<(na/ra)/(nb/rb)<0 (4) -0.6 <(na / ra) / (nb / rb) <0
但し、 However,
ra:第2補助レンズ群中の最も物体側のレンズ面の曲率半径, ra: Radius of curvature of the lens surface on the most object side in the second auxiliary lens group,
na:第2補助レンズ群中の最も物体側のレンズのd線に対する屈折率, na: Refractive index of the lens on the most object side in the second auxiliary lens group with respect to the d line,
rb:第2補助レンズ群中の最も像側のレンズ面の曲率半径, rb: Radius of curvature of the lens surface on the image side of the second auxiliary lens group,
nb:第2補助レンズ群中の最も像側のレンズのd線に対する屈折率. nb: Refractive index of the lens on the image side of the second auxiliary lens group with respect to the d line.
【0025】 0025
条件式(4)は、第2補助レンズ群の形状を適切に規定する条件式であり、像シフト時にシフトレンズ群単独によって画面中心部において発生する偏芯コマ収差を良好に補正するための条件式である。 The conditional expression (4) is a conditional expression that appropriately defines the shape of the second auxiliary lens group, and is a condition for satisfactorily correcting the eccentric coma generated in the center of the screen by the shift lens group alone at the time of image shifting. It is an expression. 上述のように、本発明によるズームレンズではシフトレンズ群単独で発生する球面収差を補正すると同時に正弦条件を満足している。 As described above, the zoom lens according to the present invention corrects the spherical aberration generated by the shift lens group alone and at the same time satisfies the sine condition.
条件式(4)の上限値を上回ると、正弦条件が大きくマイナスとなって像シフト時に画面中心部において内向性のコマ収差が大きく発生してしまう。 If the upper limit of the conditional expression (4) is exceeded, the sine condition becomes large and negative, and introverted coma aberration is greatly generated at the center of the screen during image shifting.
一方、条件式(4)の下限値を下回ると、正弦条件が大きくプラスとなって像シフト時に画面中心部において外向性のコマ収差が大きく発生してしまう。 On the other hand, if it is less than the lower limit of the conditional expression (4), the sine condition becomes large and positive, and an extroverted coma aberration is greatly generated at the center of the screen at the time of image shifting.
【0026】 0026
本発明によるズームレンズは、各レンズ群の収差補正上の機能を明確にすることによって、焦点距離状態の変化に伴う諸収差の変動を良好に補正している。 The zoom lens according to the present invention satisfactorily corrects fluctuations in various aberrations due to changes in the focal length state by clarifying the aberration correction function of each lens group.
本発明によるズームレンズは、広角端状態において、第1レンズ群と第2レンズ群との間隔をできるだけ小さくし、第2レンズ群と開口絞りとの間隔をある程度大きくする構成としている。 The zoom lens according to the present invention has a configuration in which the distance between the first lens group and the second lens group is made as small as possible and the distance between the second lens group and the aperture stop is increased to some extent in the wide-angle end state. これにより、第1レンズ群を通過する軸外光束を光軸に近づけ、第2レンズ群を通過する軸外光束を光軸から離している。 As a result, the off-axis luminous flux passing through the first lens group is brought closer to the optical axis, and the off-axis luminous flux passing through the second lens group is separated from the optical axis.
また本発明によるズームレンズは、広角端状態から望遠端状態までレンズ位置状態が変化する際に、第1レンズ群と第2レンズ群との間隔を大きくし、かつ第2レンズ群と開口絞りとの間隔を小さくするように第1レンズ群と第2レンズ群とを移動させる構成としている。 Further, in the zoom lens according to the present invention, when the lens position state changes from the wide-angle end state to the telephoto end state, the distance between the first lens group and the second lens group is increased, and the second lens group and the aperture stop are combined. The first lens group and the second lens group are moved so as to reduce the distance between the lenses. これにより、第1レンズ群を通過する軸外光束を光軸から離し、第2レンズ群を通過する軸外光束を光軸に近づけている。 As a result, the off-axis luminous flux passing through the first lens group is separated from the optical axis, and the off-axis luminous flux passing through the second lens group is brought closer to the optical axis.
このように本発明によるズームレンズでは、第1レンズ群と第2レンズ群を通過する軸外光束の高さを変化させることによって、レンズ位置状態の変化に伴って発生する軸外収差の変動を良好に補正している。 As described above, in the zoom lens according to the present invention, by changing the height of the off-axis luminous flux passing through the first lens group and the second lens group, the fluctuation of the off-axis aberration generated with the change of the lens position state is changed. It is corrected well.
【0027】 [0027]
さらに本発明によるズームレンズは、広角端状態において、第3レンズ群と第4レンズ群との間隔を大きくする構成としている。 Further, the zoom lens according to the present invention has a configuration in which the distance between the third lens group and the fourth lens group is increased in the wide-angle end state. これにより、第4レンズ群を通過する軸外光束を光軸から離している。 As a result, the off-axis luminous flux passing through the fourth lens group is separated from the optical axis.
また本発明によるズームレンズは、広角端状態から望遠端状態までレンズ位置状態が変化する際に、第3レンズ群と第4レンズ群との間隔を小さくする構成としている。 Further, the zoom lens according to the present invention has a configuration in which the distance between the third lens group and the fourth lens group is reduced when the lens position state changes from the wide-angle end state to the telephoto end state. これにより、第4レンズ群を通過する軸外光束が光軸に近づくように変化させ、レンズ位置状態の変化に伴って発生する軸外収差の変動をより良好に補正している。 As a result, the off-axis luminous flux passing through the fourth lens group is changed so as to approach the optical axis, and the fluctuation of the off-axis aberration generated with the change in the lens position state is better corrected.
【0028】 [0028]
以上のように本発明によるズームレンズは、第1レンズ群が望遠端状態において発生する軸外収差の補正を主に行い、第2レンズ群が広角端状態において発生する軸外収差の補正を主に行い、第4レンズ群も広角端状態において発生する軸外収差の補正を主に行う構成である。 As described above, the zoom lens according to the present invention mainly corrects the off-axis aberration generated in the telephoto end state of the first lens group, and mainly corrects the off-axis aberration generated in the wide-angle end state of the second lens group. The fourth lens group is also configured to mainly correct off-axis aberrations that occur in the wide-angle end state. 尚、第2レンズ群と第4レンズ群は、開口絞りを挟んでそれぞれ物体側と像側に配置されるため収差補正上の役割が異なる。 Since the second lens group and the fourth lens group are arranged on the object side and the image side with the aperture diaphragm in between, they have different roles in aberration correction.
そして本発明によるズームレンズは、開口絞りは第3レンズ群の近傍または第3レンズ群内部に配置されており、軸外光束は該第3レンズ群の光軸付近を通過するため軸外収差の発生が少ない。 In the zoom lens according to the present invention, the aperture diaphragm is arranged near the third lens group or inside the third lens group , and the off-axis light beam passes near the optical axis of the third lens group, so that the off-axis aberration occurs. There are few occurrences. このため、第3レンズ群は軸上収差の補正を主に行う。 Therefore, the third lens group mainly corrects the axial aberration.
本発明によるズームレンズは、第3レンズ群より射出される軸上光束を平行光に近づける構成としている。 The zoom lens according to the present invention has a configuration in which the axial luminous flux emitted from the third lens group is brought close to parallel light. これにより、第3レンズ群と第4レンズ群との間隔の変化によって軸上収差は変化せずに軸外収差だけを変化させることが可能となり、レンズ位置状態の変化に伴って発生する像面湾曲の変動を良好に補正している。 As a result, it is possible to change only the off-axis aberration without changing the axial aberration by changing the distance between the third lens group and the fourth lens group, and the image plane generated by the change of the lens position state. The fluctuation of curvature is corrected well.
【0029】 [0029]
条件(F)は、第3レンズ群より射出される軸外光束を平行光に近づけるための条件である。 The condition (F) is a condition for bringing the off-axis luminous flux emitted from the third lens group closer to parallel light.
本発明によるズームレンズは、第3レンズ群中の第1補助レンズ群と第2補助レンズが正の屈折力を有し、第3レンズ群から射出される軸外光束を平行光に近づける構成とするために、第3補助レンズ群が負の屈折力を有することが望ましい。 The zoom lens according to the present invention has a configuration in which the first auxiliary lens group and the second auxiliary lens in the third lens group have a positive refractive force, and the off-axis light beam emitted from the third lens group is brought close to parallel light. Therefore, it is desirable that the third auxiliary lens group has a negative refractive force.
【0030】 [0030]
特に本発明によるズームレンズは、以下の条件式(5)を満足することが望ましい。 In particular, it is desirable that the zoom lens according to the present invention satisfies the following conditional expression (5).
(5)0.5<|fc|/f3<0.9 (5) 0.5 << | fc | / f3 <0.9
但し、 However,
fc:第3補助レンズ群の焦点距離, fc: Focal length of the 3rd auxiliary lens group,
f3:第3レンズ群の焦点距離. f3: Focal length of the third lens group.
【0031】 0031
条件式(5)は、本発明によるズームレンズのより高い光学性能を実現するため、第3補助レンズ群の焦点距離を適切に規定する条件式である。 The conditional expression (5) is a conditional expression that appropriately defines the focal length of the third auxiliary lens group in order to realize higher optical performance of the zoom lens according to the present invention.
条件式(5)の上限値を上回ると、広角端状態における負の歪曲収差をより良好に補正することができなくなってしまう。 If the upper limit of the conditional expression (5) is exceeded, the negative distortion in the wide-angle end state cannot be corrected better.
条件式(5)の下限値を下回ると、第3補助レンズ群において発生する正の球面収差をより良好に補正することができなくなってしまう。 If it falls below the lower limit of the conditional expression (5), the positive spherical aberration generated in the third auxiliary lens group cannot be corrected more satisfactorily.
【0032】 [0032]
また本発明によるズームレンズは、第3補助レンズ群が、物体側に凹面を向けた負レンズを最も物体側に有し、以下の条件式(6)を満足することが望ましい。 Further, in the zoom lens according to the present invention, it is desirable that the third auxiliary lens group has a negative lens having a concave surface facing the object side most on the object side, and satisfies the following conditional expression (6).
(6)0.5<|rc|/f3<0.75 (6) 0.5 <| rc | / f3 <0.75
但し、 However,
rc:第3補助レンズ群中の最も物体側に配置された負レンズの物体側のレンズ面の曲率半径, rc: Radius of curvature of the lens surface of the negative lens placed on the object side of the third auxiliary lens group on the object side,
f3:第3レンズ群の焦点距離. f3: Focal length of the third lens group.
【0033】 0033
条件式(6)は、像シフト時に発生する諸収差の変動のより良好な補正を行うための条件式であり、第3補助レンズ群中の最も物体側に配置された負レンズの物体側のレンズ面の曲率半径を規定する条件式である。 The conditional expression (6) is a conditional expression for better correcting the fluctuation of various aberrations generated at the time of image shift, and is the conditional expression on the object side of the negative lens arranged on the object side most in the third auxiliary lens group. This is a conditional expression that defines the radius of curvature of the lens surface.
条件式(6)の上限値を上回ると、像シフト時、広角端状態において画面周辺部の性能劣化が大きくなってしまう。 If the upper limit of the conditional expression (6) is exceeded, the performance deterioration of the peripheral portion of the screen becomes large in the wide-angle end state at the time of image shifting.
一方、条件式(6)の下限値を下回ると、像シフト時、望遠端状態において画面中心部の性能劣化が大きくなってしまう。 On the other hand, if it is less than the lower limit of the conditional expression (6), the performance deterioration of the central part of the screen becomes large in the telephoto end state at the time of image shift.
【0034】 0034
本発明によるズームレンズは、非球面レンズを適切に配置することによって、より高い光学性能を実現することが可能である。 The zoom lens according to the present invention can realize higher optical performance by appropriately arranging an aspherical lens.
レンズ位置状態にかかわらず画面中心部の光学性能の向上を図るためには、第3レンズ群における第1補助レンズ群中の1つのレンズ面を非球面とすることが望ましい。 In order to improve the optical performance of the central part of the screen regardless of the lens position state, it is desirable that one lens surface in the first auxiliary lens group in the third lens group is an aspherical surface.
広角端状態において画角の変化によるコマ収差の変動を極めて良好に補正するためには、第2レンズ群中或いは第4レンズ群中の少なくとも1つのレンズ面を非球面とすることが望ましい。 In order to correct the fluctuation of coma due to the change of the angle of view in the wide-angle end state extremely well, it is desirable that at least one lens surface in the second lens group or the fourth lens group is an aspherical surface. また、第2レンズ群と第4レンズ群の両方に非球面レンズを配置することによってさらなる高性能化を図ることも可能である。 Further, it is possible to further improve the performance by arranging aspherical lenses in both the second lens group and the fourth lens group.
【0035】 0035.
尚、本発明によるズームレンズは近距離合焦時に第2レンズ群を光軸方向に移動させる構成とすることが、諸収差の変動を抑えるために適している。 The zoom lens according to the present invention is suitable for suppressing fluctuations in various aberrations by moving the second lens group in the optical axis direction during short-distance focusing.
また本発明は、ズームレンズに限られるものでなく、例えば焦点距離状態が連続的に存在しない、いわゆるバリフォーカルズームレンズに適用することもできる。 Further, the present invention is not limited to the zoom lens, and can be applied to, for example, a so-called varifocal zoom lens in which the focal length state does not continuously exist.
さらに本発明によるズームレンズは、第4レンズ群の像側に付加的なレンズを配置することによって射出瞳位置を像面位置から遠ざけ、CCD等の光電変換素子を受光素子として用いる光学系に適用することも可能である。 Further, the zoom lens according to the present invention is applied to an optical system in which a photoelectric conversion element such as a CCD is used as a light receiving element by arranging an additional lens on the image side of the fourth lens group to move the exit pupil position away from the image plane position. It is also possible to do. これは光電変換素子を受光素子として用いた場合に、素子面の直前にマイクロレンズアレイを配置するために射出瞳位置を像面位置から遠ざける必要があるからである。 This is because when the photoelectric conversion element is used as the light receiving element, it is necessary to move the exit pupil position away from the image plane position in order to arrange the microlens array immediately in front of the element surface. 尚、受光光量が少ない場合ノイズが発生しやすく、短時間での露出を行うことができないという問題を生じるため、マイクロレンズアレイは受光光量を増大させる目的で配置される。 When the amount of received light is small, noise is likely to occur, which causes a problem that exposure cannot be performed in a short time. Therefore, the microlens array is arranged for the purpose of increasing the amount of received light.
【0036】 0036
【実施例】 【Example】
以下、本発明の各実施例に係るズームレンズを添付図面に基づいて説明する。 Hereinafter, the zoom lens according to each embodiment of the present invention will be described with reference to the accompanying drawings.
各実施例において、非球面の形状は以下の非球面式で表される。 In each embodiment, the shape of the aspherical surface is represented by the following aspherical surface equation. 尚、yは光軸からの高さ、xはサグ量、cは基準曲率(近軸曲率)、κは円錐定数、C 4 ,C 6 ,C 8 ,C 10は各々4,6,8,10次の非球面係数とする。 In addition, y is the height from the optical axis, x is the sag amount, c is the reference curvature (paraxial curvature), κ is the conical constant, C 4 , C 6 , C 8 and C 10 are 4, 6, 8 respectively. It is a 10th-order aspherical coefficient.
【0037】 0037
【数1】 [Number 1]
x=cy 2 /{1+(1−κc 221/2 }+C 44 +C 66 +C 88 +C 1010 x = cy 2 / {1 + (1-κc 2 y 2 ) 1/2 } + C 4 y 4 + C 6 y 6 + C 8 y 8 + C 10 y 10
【0038】 [0038]
図1は、本発明の各実施例に係る可変焦点距離レンズ系(ズームレンズ)の屈折力配分を示す図である。 FIG. 1 is a diagram showing the refractive power distribution of the variable focal length lens system (zoom lens) according to each embodiment of the present invention.
本発明の各実施例に係るズームレンズは、物体側より順に、正の屈折力を有する第1レンズ群G1と、負の屈折力を有する第2レンズ群G2と、正の屈折力を有する第3レンズ群G3と、正の屈折力を有する第4レンズ群G4とから構成されている。 The zoom lens according to each embodiment of the present invention has a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, and a first lens group having a positive refractive power in order from the object side. It is composed of three lens groups G3 and a fourth lens group G4 having a positive refractive power. そして、広角端状態(W)から望遠端状態(T)への変倍に際し、第1レンズ群G1と第2レンズ群G2との空気間隔が増大し、第2レンズ群G2と第3レンズ群G3との空気間隔が減少し、第3レンズ群G3と第4レンズ群G4との空気間隔は減少するように、少なくとも第1レンズ群G1及び第4レンズ群G4が物体側へ移動する。 Then, when the magnification is changed from the wide-angle end state (W) to the telescopic end state (T), the air gap between the first lens group G1 and the second lens group G2 increases, and the second lens group G2 and the third lens group At least the first lens group G1 and the fourth lens group G4 move toward the object so that the air distance between the third lens group G3 and the fourth lens group G4 decreases.
【0039】 [0039]
(第1実施例) (First Example)
図2は、本発明の第1実施例に係るズームレンズのレンズ構成を示す図である。 FIG. 2 is a diagram showing a lens configuration of a zoom lens according to a first embodiment of the present invention.
本実施例に係るズームレンズにおいて第1レンズ群G1は、物体側から順に、物体側に凸面を向けたメニスカス形状の負レンズと物体側に凸面を向けた正レンズとの接合レンズL11と、物体側に凸面を向けたメニスカス形状の正レンズL12とから構成されている。 In the zoom lens according to the present embodiment, the first lens group G1 is a junction lens L11 of a meniscus-shaped negative lens having a convex surface facing the object side and a positive lens having a convex surface facing the object side, and an object in order from the object side. It is composed of a meniscus-shaped positive lens L12 with a convex surface facing to the side.
第2レンズ群G2は、物体側から順に、像側に凹面を向けた負レンズL21と、物体側に凹面を向けた負レンズL22と、物体側に凸面を向けた正レンズL23と、物体側に凹面を向けた負レンズL24とから構成されている。 The second lens group G2 includes a negative lens L21 having a concave surface facing the image side, a negative lens L22 having a concave surface facing the object side, a positive lens L23 having a convex surface facing the object side, and an object side in this order from the object side. It is composed of a negative lens L24 having a concave surface facing the surface.
第3レンズ群G3は、物体側から順に、両凸形状の正レンズと物体側に凹面を向けた負レンズとの接合正レンズL31と、両凸形状の正レンズと物体側に凹面を向けた負レンズとの接合正レンズL32と、物体側に凹面を向けた負レンズL33とから構成されている。 The third lens group G3 is a junction positive lens L31 of a biconvex positive lens and a negative lens having a concave surface facing the object side, and a biconvex positive lens and a concave surface facing the object side in order from the object side. It is composed of a positive lens L32 joined with a negative lens and a negative lens L33 with a concave surface facing the object side.
第4レンズ群G4は、物体側から順に、像側に凸面を向けた正レンズL41と、両凸形状の正レンズと物体側に凹面を向けた負レンズとの接合レンズL42とから構成されている。 The fourth lens group G4 is composed of a positive lens L41 having a convex surface facing the image side and a junction lens L42 of a biconvex positive lens and a negative lens having a concave surface facing the object side in order from the object side. There is.
【0040】 0040
本実施例に係るズームレンズにおいて開口絞りSは、第3レンズ群G3の物体側に配置され、レンズ位置状態が変化する際に第3レンズ群G3と共に移動する。 In the zoom lens according to the present embodiment, the aperture diaphragm S is arranged on the object side of the third lens group G3 and moves together with the third lens group G3 when the lens position state changes.
また、第2レンズ群G2中の負レンズL21は、物体側レンズ面に非球面形状の薄いプラスチック樹脂層を備えている。 Further, the negative lens L21 in the second lens group G2 is provided with a thin plastic resin layer having an aspherical shape on the lens surface on the object side.
また、本実施例に係るズームレンズは、第3レンズ群G3中の接合正レンズL31が第1補助レンズ群、接合正レンズL32が第2補助レンズ群、負レンズL33が第3補助レンズ群としてそれぞれ機能する構成である。 Further, in the zoom lens according to the present embodiment, the junction positive lens L31 in the third lens group G3 is the first auxiliary lens group, the junction positive lens L32 is the second auxiliary lens group, and the negative lens L33 is the third auxiliary lens group. Each is a functional configuration.
【0041】 [0041]
以下の表1に、本発明の第1実施例に係るズームレンズの諸元の値を掲げる。 Table 1 below lists the specifications of the zoom lens according to the first embodiment of the present invention.
(全体諸元)において、fは焦点距離、FNOはFナンバー、2ωは画角(単位:度)をそれぞれ示す。 In (overall specifications), f indicates the focal length, FNO indicates the F number, and 2ω indicates the angle of view (unit: degree).
(レンズデータ)において、面は物体側からのレンズ面の順序、間隔はレンズ面の間隔をそれぞれ示す。 In (lens data), the surface indicates the order of the lens surfaces from the object side, and the spacing indicates the spacing between the lens surfaces. また、屈折率はd線(λ=587.6nm)に対する値である。 The refractive index is a value with respect to the d line (λ = 587.6 nm). さらに、曲率半径0.0000は平面を示し、Bfはバックフォーカスを示す。 Further, a radius of curvature of 0.0000 indicates a plane, and Bf indicates a back focus.
【0042】 [0042]
ここで、以下の全ての諸元値において掲載されている焦点距離f、曲率半径、間隔、その他長さの単位は一般に「mm」が使われる。 Here, "mm" is generally used as the unit of the focal length f, the radius of curvature, the interval, and other lengths listed in all the following specification values. しかし光学系は、比例拡大または比例縮小しても同等の光学性能が得られるため、これに限られるものではない。 However, the optical system is not limited to this because the same optical performance can be obtained even if the optical system is proportionally expanded or decreased.
尚、以下の全実施例の諸元値において、本実施例と同様の符号を用いる。 In addition, in the specification values ​​of all the following examples, the same reference numerals as those of this embodiment are used.
【0043】 [0043]
【表1】 [Table 1]
(非球面係数) (Aspherical coefficient)
第6レンズ面と第16レンズ面と第25レンズ面とは非球面であり、それぞれの非球面係数を以下に示す。 The 6th lens surface, the 16th lens surface, and the 25th lens surface are aspherical surfaces, and their respective aspherical surface coefficients are shown below.
(可変間隔データ) (Variable interval data)
レンズ位置状態が変化する際の可変間隔を以下に示す。 The variable interval when the lens position state changes is shown below.
(シフトレンズ群のシフト量)半画角0.3度に相当する量だけ像シフトさせるために必要な第2補助レンズ群のシフト量δbを以下に示す。 (Shift amount of shift lens group) The shift amount δb of the second auxiliary lens group required to shift the image by an amount corresponding to a half angle of view of 0.3 degrees is shown below.
【0044】 [0044]
図3(a),(b),(c)はそれぞれ、本発明の第1実施例に係るズームレンズの広角端状態(f=28.80)、中間焦点距離状態(f=100.00)、望遠端状態(f=291.00)における無限遠合焦時の諸収差図である。 3A, 3B, and 3C show a wide-angle end state (f = 28.80) and an intermediate focal length state (f = 100.00) of the zoom lens according to the first embodiment of the present invention, respectively. It is a diagram of various aberrations at the time of focusing at infinity in the telephoto end state (f = 291.00).
図4(a),(b),(c)はそれぞれ、本発明の第1実施例に係るズームレンズの広角端状態(f=28.80)、中間焦点距離状態(f=100.00)、望遠端状態(f=291.00)における無限遠合焦時に第2補助レンズ群を上記表1に示す量だけシフトさせた際のコマ収差図である。 4 (a), (b), and (c) show the wide-angle end state (f = 28.80) and the intermediate focal length state (f = 100.00) of the zoom lens according to the first embodiment of the present invention, respectively. It is a coma aberration diagram when the second auxiliary lens group is shifted by the amount shown in Table 1 at the time of infinity focusing in the telephoto end state (f = 291.00).
【0045】 0045
図3及び図4は、d線(λ=587.6nm)の収差を示す収差図である。 3 and 4 are aberration diagrams showing aberrations on the d-line (λ = 587.6 nm).
図3(a),(b),(c)において、FNOはFナンバー、ωは半画角、Yは像高をそれぞれ示す。 In FIGS. 3A, 3B, and 3C, FNO indicates an F number, ω indicates a half angle of view, and Y indicates an image height. 球面収差図では最大口径に対応するFナンバーの値を示し、非点収差図及び歪曲収差図では像高の最大値をそれぞれ示す。 The spherical aberration diagram shows the value of the F number corresponding to the maximum aperture, and the astigmatism diagram and the distortion diagram show the maximum value of the image height, respectively. また、コマ収差図では各半画角と各像高0、10.8、15.12、18.34、21.6の値を示す。 Further, in the coma aberration diagram, the values ​​of each half angle of view and each image height 0, 10.8, 15.12, 18.34, and 21.6 are shown. さらに、球面収差図において、実線は球面収差、点線はサイン・コンディションをそれぞれ示す。 Further, in the spherical aberration diagram, the solid line shows the spherical aberration and the dotted line shows the sine condition. 非点収差図において、実線はサジタル像面、破線はメリディオナル像面をそれぞれ示す。 In the astigmatism diagram, the solid line shows the sagittal image plane and the broken line shows the meridional image plane.
図4(a),(b),(c)において、ωは半画角、Yは像高をそれぞれ示す。 In FIGS. 4A, 4B, and 4C, ω indicates a half angle of view and Y indicates an image height. また図4は、像高Y=−15.0,0.0,+15.0の値を示す。 Further, FIG. 4 shows the values ​​of the image height Y = -15.0, 0.0, + 15.0.
尚、以下に示す各実施例の諸収差図において、本実施例と同様の符号を用いる。 In addition, in the various aberration diagrams of each example shown below, the same reference numerals as those of this example are used.
【0046】 [0046]
図3(a),(b),(c)より、本実施例に係るズームレンズは、諸収差を良好に補正し、優れた結像性能を有していることがわかる。 From FIGS. 3A, 3B, and 3C, it can be seen that the zoom lens according to this embodiment satisfactorily corrects various aberrations and has excellent imaging performance.
図4(a),(b),(c)より、本実施例に係るズームレンズは、像シフト時における諸収差の変動を良好に補正していることがわかる。 From FIGS. 4A, 4B, and 4C, it can be seen that the zoom lens according to this embodiment satisfactorily corrects fluctuations in various aberrations during image shifting.
【0047】 [0047]
(第2実施例) (Second Example)
図5は、本発明の第2実施例に係るズームレンズのレンズ構成を示す図である。 FIG. 5 is a diagram showing a lens configuration of a zoom lens according to a second embodiment of the present invention.
本実施例に係るズームレンズにおいて第1レンズ群G1は、物体側から順に、物体側に凸面を向けたメニスカス形状の負レンズと物体側に凸面を向けた正レンズとの接合レンズL11と、物体側に凸面を向けたメニスカス形状の正レンズL12とから構成されている。 In the zoom lens according to the present embodiment, the first lens group G1 is a junction lens L11 of a meniscus-shaped negative lens having a convex surface facing the object side and a positive lens having a convex surface facing the object side, and an object in order from the object side. It is composed of a meniscus-shaped positive lens L12 with a convex surface facing to the side.
第2レンズ群G2は、物体側から順に、像側に凹面を向けた負レンズL21と、物体側に凹面を向けた負レンズL22と、物体側に凸面を向けた正レンズL23と、物体側に凹面を向けた負レンズL24とから構成されている。 The second lens group G2 includes a negative lens L21 having a concave surface facing the image side, a negative lens L22 having a concave surface facing the object side, a positive lens L23 having a convex surface facing the object side, and an object side in this order from the object side. It is composed of a negative lens L24 having a concave surface facing the surface.
第3レンズ群G3は、物体側から順に、両凸レンズと物体側に凹面を向けた負レンズとの接合正レンズL31,物体側に凸面を向けた正レンズL32と、両凸形状の正レンズと物体側に凹面を向けた負レンズとの接合正レンズL33と、両凹形状の負レンズと像側に凸面を向けた正レンズとの接合負レンズL34とから構成されている。 The third lens group G3 includes a biconvex lens and a negative lens having a concave surface facing the object side, a positive lens L31, a positive lens L32 having a convex surface facing the object side, and a biconvex positive lens in order from the object side. It is composed of a bonded positive lens L33 with a negative lens having a concave surface facing the object side and a bonded negative lens L34 having a negative lens having a biconcave shape and a positive lens having a convex surface facing the image side.
第4レンズ群G4は、物体側から順に、像側に凸面を向けた正レンズL41と、両凸形状の正レンズと物体側に凹面を向けた負レンズとの接合レンズL42とから構成されている。 The fourth lens group G4 is composed of a positive lens L41 having a convex surface facing the image side and a junction lens L42 of a biconvex positive lens and a negative lens having a concave surface facing the object side in order from the object side. There is.
【0048】 0048
本実施例に係るズームレンズにおいて開口絞りSは、第3レンズ群G3中に配置され、レンズ位置状態が変化する際に第3レンズ群G3と共に移動する。 In the zoom lens according to the present embodiment, the aperture diaphragm S is arranged in the third lens group G3 and moves together with the third lens group G3 when the lens position state changes.
また、第2レンズ群G2中の負レンズL21は、物体側レンズ面に非球面形状の薄いプラスチック樹脂層を備えている。 Further, the negative lens L21 in the second lens group G2 is provided with a thin plastic resin layer having an aspherical shape on the lens surface on the object side.
また本実施例に係るズームレンズは、第3レンズ群G3中の接合正レンズL31と正レンズL32とが第1補助レンズ群、接合正レンズL33が第2補助レンズ群、接合負レンズL34が第3補助レンズ群としてそれぞれ機能する構成である。 Further, in the zoom lens according to the present embodiment, the junction positive lens L31 and the positive lens L32 in the third lens group G3 are the first auxiliary lens group, the junction positive lens L33 is the second auxiliary lens group, and the junction negative lens L34 is the first. It is a configuration that functions as each of the three auxiliary lens groups.
以下の表2に、本発明の第2実施例に係るズームレンズの諸元の値を掲げる。 Table 2 below lists the specifications of the zoom lens according to the second embodiment of the present invention.
【0049】 [0049]
【表2】 [Table 2]
(非球面係数) (Aspherical coefficient)
第6レンズ面と第18レンズ面と第28レンズ面とは非球面であり、それぞれの非球面係数を以下に示す。 The 6th lens surface, the 18th lens surface, and the 28th lens surface are aspherical surfaces, and their respective aspherical surface coefficients are shown below.
(可変間隔データ) (Variable interval data)
レンズ位置状態が変化する際の可変間隔を以下に示す。 The variable interval when the lens position state changes is shown below.
(シフトレンズ群のシフト量) (Shift amount of shift lens group)
半画角0.3度に相当する量だけ像シフトさせるために必要な第2補助レンズ群のシフト量δbを以下に示す。 The shift amount δb of the second auxiliary lens group required to shift the image by an amount corresponding to a half angle of view of 0.3 degrees is shown below.
【0050】 0050
図6(a),(b),(c)はそれぞれ、本発明の第2実施例に係るズームレンズの広角端状態(f=28.80)、中間焦点距離状態(f=100.00)、望遠端状態(f=290.99)における無限遠合焦時の諸収差図である。 6 (a), (b), and (c) show the wide-angle end state (f = 28.80) and the intermediate focal length state (f = 100.00) of the zoom lens according to the second embodiment of the present invention, respectively. , It is a diagram of various aberrations at the time of focusing at infinity in the telephoto end state (f = 290.99).
図7(a),(b),(c)はそれぞれ、本発明の第2実施例に係るズームレンズの広角端状態(f=28.80)、中間焦点距離状態(f=100.00)、望遠端状態(f=290.99)における無限遠合焦時に第2補助レンズ群を上記表2に示す量だけシフトさせた際のコマ収差図である。 7 (a), (b), and (c) show the wide-angle end state (f = 28.80) and the intermediate focal length state (f = 100.00) of the zoom lens according to the second embodiment of the present invention, respectively. It is a coma aberration diagram when the second auxiliary lens group is shifted by the amount shown in Table 2 at the time of infinity focusing in the telephoto end state (f = 290.99).
【0051】 0051
図6(a),(b),(c)より、本実施例に係るズームレンズは、諸収差を良好に補正し、優れた結像性能を有していることがわかる。 From FIGS. 6A, 6B, and 6C, it can be seen that the zoom lens according to this embodiment satisfactorily corrects various aberrations and has excellent imaging performance.
図7(a),(b),(c)より、本実施例に係るズームレンズは、像シフト時における諸収差の変動を良好に補正していることがわかる。 From FIGS. 7A, 7B, and 7C, it can be seen that the zoom lens according to this embodiment satisfactorily corrects fluctuations in various aberrations during image shifting.
【0052】 [0052]
(第3実施例) (Third Example)
図8は、本発明の第3実施例に係るズームレンズのレンズ構成を示す図である。 FIG. 8 is a diagram showing a lens configuration of a zoom lens according to a third embodiment of the present invention.
本実施例に係るズームレンズにおいて第1レンズ群G1は、物体側から順に、物体側に凸面を向けたメニスカス形状の負レンズと物体側に凸面を向けた正レンズとの接合レンズL11と、物体側に凸面を向けたメニスカス形状の正レンズL12とから構成されている。 In the zoom lens according to the present embodiment, the first lens group G1 is a junction lens L11 of a meniscus-shaped negative lens having a convex surface facing the object side and a positive lens having a convex surface facing the object side, and an object in order from the object side. It is composed of a meniscus-shaped positive lens L12 with a convex surface facing to the side.
第2レンズ群G2は、物体側から順に、像側に凹面を向けた負レンズL21と、物体側に凹面を向けた負レンズL22と、物体側に凸面を向けた正レンズL23と、物体側に凹面を向けた負レンズL24とから構成されている。 The second lens group G2 includes a negative lens L21 having a concave surface facing the image side, a negative lens L22 having a concave surface facing the object side, a positive lens L23 having a convex surface facing the object side, and an object side in this order from the object side. It is composed of a negative lens L24 having a concave surface facing the surface.
第3レンズ群G3は、物体側から順に、両凸形状の正レンズと物体側に凹面を向けた負レンズとの接合正レンズL31と、物体側に凸面を向けた正レンズL32と、両凸形状の正レンズと物体側に凹面を向けた負レンズとの接合正レンズL33と、両凹形状の負レンズと物体側に凸面を向けた正メニスカスレンズとの接合負レンズL34とから構成されている。 The third lens group G3 includes a biconvex positive lens and a negative lens with a concave surface facing the object side, a positive lens L31, a positive lens L32 with a convex surface facing the object side, and a biconvex lens in order from the object side. It is composed of a positive lens L33, which is a junction of a positive lens with a shape and a negative lens with a concave surface facing the object side, and a negative lens L34, which is a junction of a negative lens with a biconcave shape and a positive meniscus lens with a convex surface facing the object side. There is.
第4レンズ群G4は、物体側から順に、像側に凸面を向けた正レンズL41と、両凸形状の正レンズと物体側に凹面を向けた負レンズとの接合レンズL42とから構成されている。 The fourth lens group G4 is composed of a positive lens L41 having a convex surface facing the image side and a junction lens L42 of a biconvex positive lens and a negative lens having a concave surface facing the object side in order from the object side. There is.
【0053】 [0053]
本実施例に係るズームレンズにおいて開口絞りSは、第3レンズ群G3中に配置され、レンズ位置状態が変化する際に第3レンズ群G3と共に移動する。 In the zoom lens according to the present embodiment, the aperture diaphragm S is arranged in the third lens group G3 and moves together with the third lens group G3 when the lens position state changes.
また、第2レンズ群G2中の負レンズL21は、物体側レンズ面に非球面形状の薄いプラスチック樹脂層を備えている。 Further, the negative lens L21 in the second lens group G2 is provided with a thin plastic resin layer having an aspherical shape on the lens surface on the object side.
また、本実施例に係るズームレンズは、第3レンズ群G3中の接合正レンズL31と正レンズL32とが第1補助レンズ群、接合正レンズL33が第2補助レンズ群、接合負レンズL34が第3補助レンズ群として機能する構成である。 Further, in the zoom lens according to the present embodiment, the junction positive lens L31 and the positive lens L32 in the third lens group G3 are the first auxiliary lens group, the junction positive lens L33 is the second auxiliary lens group, and the junction negative lens L34. It is a configuration that functions as a third auxiliary lens group.
以下の表3に、本発明の第3実施例に係るズームレンズの諸元の値を掲げる。 Table 3 below lists the specifications of the zoom lens according to the third embodiment of the present invention.
【0054】 0054
(表3) (Table 3)
(全体諸元) (Overall specifications)
広角端状態 中間焦点距離状態 望遠端状態f 28.80 〜 100.00 〜 291.01 Wide-angle end state Intermediate focal length state Telephoto end state f 28.80 ~ 100.00 ~ 291.01
FNO 3.70 〜 5.32 〜 5.90 FNO 3.70 ~ 5.32 ~ 5.90
2ω 76.77 〜 23.72 〜 8.27° 2ω 76.77 ~ 23.72 ~ 8.27 °
(レンズデータ) (Lens data)
面 曲率半径 間隔 屈折率 アッベ数Surface radius of curvature interval Refractive index Abbe number
1 92.4229 1.900 1.84666 23.78 1 92.4229 1.900 1.84666 23.78
2 66.7560 7.750 1.49700 81.61 2 66.7560 7.750 1.49700 81.61
3 -846.2717 0.100 1.0 3 -846.2717 0.100 1.0
4 63.6267 4.950 1.49700 81.61 4 63.6267 4.950 1.49700 81.61
5 165.9874 (D5) 1.0 5 165.9874 (D5) 1.0
6 128.4411 0.200 1.51742 52.42 6 128.4411 0.200 1.51742 52.42
7 101.5414 1.150 1.72916 54.66 7 101.5414 1.150 1.72916 54.66
8 17.1504 6.250 1.0 8 17.1504 6.250 1.0
9 -46.5218 1.000 1.75500 52.32 9 -46.5218 1.000 1.75500 52.32
10 66.4470 0.100 1.0 10 66.4470 0.100 1.0
11 33.9329 4.200 1.84666 23.78 11 33.9329 4.200 1.84666 23.78
12 -53.7522 1.800 1.0 12 -53.7522 1.800 1.0
13 -26.2934 0.900 1.83481 42.72 13 -26.2934 0.900 1.83481 42.72
14 -885.5810 (D14) 1.0 14 -885.5810 (D14) 1.0
15 0.0000 2.200 1.0 (開口絞り) 15 0.0000 2.200 1.0 (Aperture aperture)
16 23.3505 7.000 1.58913 61.18 16 23.3505 7.000 1.58913 61.18
17 -25.1524 0.800 1.80400 46.58 17 -25.1524 0.800 1.80400 46.58
18 -280.9645 0.100 1.0 18 -280.9645 0.100 1.0
19 37.9321 3.200 1.51633 64.14 19 37.9321 3.200 1.51633 64.14
20 -414.9721 4.050 1.0 20 -414.9721 4.050 1.0
21 34.8328 3.850 1.75500 52.32 21 34.8328 3.850 1.75500 52.32
22 -60.1069 0.800 1.84666 23.78 22 -60.1069 0.800 1.84666 23.78
23 -456.9696 3.100 1.0 23 -456.9696 3.100 1.0
24 -21.2766 0.800 1.83400 37.17 24-21.2766 0.800 1.83400 37.17
25 32.5985 2.650 1.48749 70.24 25 32.5985 2.650 1.48749 70.24
26 863.3676 (D26) 1.0 26 863.3676 (D26) 1.0
27 145.6193 3.600 1.51633 64.14 27 145.6193 3.600 1.51633 64.14
28 -30.7860 0.100 1.0 28 -30.7860 0.100 1.0
29 629.7219 7.700 1.66680 33.04 29 629.7219 7.700 1.66680 33.04
30 -13.2652 0.900 1.83481 42.72 30 -13.2652 0.900 1.83481 42.72
31 -80.0893 (Bf) 1.0 31 -80.0893 (Bf) 1.0
(非球面係数) (Aspherical coefficient)
第6レンズ面と第16レンズ面と第28レンズ面とは非球面であり、それぞれの非球面係数を以下に示す。 The 6th lens surface, the 16th lens surface, and the 28th lens surface are aspherical surfaces, and their respective aspherical surface coefficients are shown below.
[第6面] [Sixth page]
κ=-4.2585 C 4 =+4.4810×10 66 =+1.2417×10 8 κ = -4.2585 C 4 = + 4.4810 × 10 6 C 6 = + 1.2417 × 10 8
8 =-1.0672×10 1010 =+3.1231×10 13 C 8 = -1.0672 × 10 10 C 10 = +3.1 231 × 10 13
[第16面] [Surface 16]
κ=1.0000 C 4 =-3.9585×10 66 =+4.2904×10 9 κ = 1.000 C 4 = -3.9585 × 10 6 C 6 = + 4.2904 × 10 9
8 =-8.0515×10 1210 =+4.2777×10 14 C 8 = -8.0515 × 10 12 C 10 = +4.2777 × 10 14
[第28面] [Surface 28]
κ=1.0000 C 4 =+1.0383×10 56 =-1.4668×10 8 κ = 1.000 C 4 = + 1.0383 × 10 5 C 6 = -1.4668 × 10 8
8 =+1.2224×10 1010 =-1.4347×10 12 C 8 = +1.2224 × 10 10 C 10 = -1.4347 × 10 12
(可変間隔データ) (Variable interval data)
レンズ位置状態が変化する際の可変間隔を以下に示す。 The variable interval when the lens position state changes is shown below.
広角端状態 中間焦点距離状態 望遠端状態f 28.8001 100.0017 291.0077 Wide-angle end state Intermediate focal length state Telephoto end state f 28.8001 100.0017 291.0077
D7 1.5358 36.1674 61.1207 D7 1.5358 36.1674 61.1207
D16 27.1675 12.0649 0.8000 D16 27.1675 12.0649 0.8000
D23 6.3826 2.6488 2.0000 D23 6.3826 2.6488 2.0000
BF 39.5003 75.7001 90.8947 BF 39.5003 75.7001 90.8947
(シフトレンズ群のシフト量) (Shift amount of shift lens group)
半画角0.3度に相当する量だけ像シフトさせるために必要な第2補助レンズ群のシフト量δbを以下に示す。 The shift amount δb of the second auxiliary lens group required to shift the image by an amount corresponding to a half angle of view of 0.3 degrees is shown below.
広角端状態 中間焦点距離状態 望遠端状態f 28.8001 100.0017 291.0077 Wide-angle end state Intermediate focal length state Telephoto end state f 28.8001 100.0017 291.0077
δb 0.1123 0.2444 0.6095 δb 0.1123 0.2444 0.6095
(条件式対応値) (Conditional expression corresponding value)
fA =224.755 fA = 224.755
fa = 30.182 fa = 30.182
fc =-19.750 fc = -19.750
f3 = 35.153 f3 = 35.153
(1)Ds/fw = 0.602 (1) Ds / fw = 0.602
(2)ft/fA = 1.295 (2) ft / fA = 1.295
(3)fa/ft = 0.104 (3) fa / ft = 0.104
(4)(na/ra)/(nb/rb) = -0.080 (4) (na / ra) / (nb / rb) = -0.080
(5)|fc|/f3 = 0.562 (5) | fc | / f3 = 0.562
(6)|rc|/f3 = 0.605 (6) | rc | / f3 = 0.605
【0055】 0055
図9(a),(b),(c)はそれぞれ、本発明の第3実施例に係るズームレンズの広角端状態(f=28.80)、中間焦点距離状態(f=100.00)、望遠端状態(f=291.00)における無限遠合焦時の諸収差図を示す。 9 (a), (b), and (c) show the wide-angle end state (f = 28.80) and the intermediate focal length state (f = 100.00) of the zoom lens according to the third embodiment of the present invention, respectively. , The various aberration diagrams at the time of focusing at infinity in the telephoto end state (f = 291.00) are shown.
図10(a),(b),(c)はそれぞれ、本発明の第3実施例に係るズームレンズの広角端状態(f=28.80)、中間焦点距離状態(f=100.00)、望遠端状態(f=291.00)における無限遠合焦時に第2補助レンズ群を上記表3に示す量だけシフトさせた際のコマ収差図を示す。 10 (a), (b), and (c) show the wide-angle end state (f = 28.80) and the intermediate focal length state (f = 100.00) of the zoom lens according to the third embodiment of the present invention, respectively. The coma aberration diagram when the second auxiliary lens group is shifted by the amount shown in Table 3 above at the time of infinity focusing in the telephoto end state (f = 291.00) is shown.
【0056】 0056
図9(a),(b),(c)より、本実施例に係るズームレンズは、諸収差を良好に補正し、優れた結像性能を有していることがわかる。 From FIGS. 9A, 9B, and 9C, it can be seen that the zoom lens according to this embodiment satisfactorily corrects various aberrations and has excellent imaging performance.
図10(a),(b),(c)より、本実施例に係るズームレンズは、像シフト時における諸収差の変動を良好に補正していることがわかる。 From FIGS. 10A, 10B, and 10C, it can be seen that the zoom lens according to this embodiment satisfactorily corrects fluctuations in various aberrations during image shifting.
【0057】 [0057]
【発明の効果】 【The invention's effect】
本発明によれば、広角端状態におけるレンズ全長が比較的短く、広角端状態から望遠端状態までレンズ位置状態が変化する際のレンズ全長の変化が少なく、レンズ系を構成する一部のレンズを光軸に対して略垂直な方向へ移動させることによって像を移動させることが可能な高変倍比のズームレンズを提供することができる。 According to the present invention, the total length of the lens in the wide-angle end state is relatively short, the change in the total length of the lens when the lens position state changes from the wide-angle end state to the telephoto end state is small, and some lenses constituting the lens system can be used. It is possible to provide a zoom lens having a high magnification ratio capable of moving an image by moving the image in a direction substantially perpendicular to the optical axis.
【図面の簡単な説明】 [Simple explanation of drawings]
【図1】本発明の各実施例に係る可変焦点距離レンズ系(ズームレンズ)の屈折力配分を示す図である。 FIG. 1 is a diagram showing the refractive power distribution of a variable focal length lens system (zoom lens) according to each embodiment of the present invention.
【図2】本発明の第1実施例に係るズームレンズのレンズ構成を示す図である。 FIG. 2 is a diagram showing a lens configuration of a zoom lens according to a first embodiment of the present invention.
【図3】(a),(b),(c)はそれぞれ、本発明の第1実施例に係るズームレンズの広角端状態(f=28.80)、中間焦点距離状態(f=100.00)、望遠端状態(f=291.00)における無限遠合焦時の諸収差図である。 3A, 3B, and 3C show a wide-angle end state (f = 28.80) and an intermediate focal length state (f = 100.) Of the zoom lens according to the first embodiment of the present invention, respectively. 00), it is a diagram of various aberrations at the time of focusing at infinity in the telephoto end state (f = 291.00).
【図4】(a),(b),(c)はそれぞれ、本発明の第1実施例に係るズームレンズの広角端状態(f=28.80)、中間焦点距離状態(f=100.00)、望遠端状態(f=291.00)における無限遠合焦時に第2補助レンズ群をシフトさせた際のコマ収差図である。 4 (a), (b), and (c) show a wide-angle end state (f = 28.80) and an intermediate focal length state (f = 100.) Of the zoom lens according to the first embodiment of the present invention, respectively. 00), is a coma aberration diagram when the second auxiliary lens group is shifted at the time of infinity focusing in the telephoto end state (f = 291.00).
【図5】本発明の第2実施例に係るズームレンズのレンズ構成を示す図である。 FIG. 5 is a diagram showing a lens configuration of a zoom lens according to a second embodiment of the present invention.
【図6】(a),(b),(c)はそれぞれ、本発明の第2実施例に係るズームレンズの広角端状態(f=28.80)、中間焦点距離状態(f=100.00)、望遠端状態(f=290.99)における無限遠合焦時の諸収差図である。 6 (a), (b), and (c) show a wide-angle end state (f = 28.80) and an intermediate focal length state (f = 100.) Of the zoom lens according to the second embodiment of the present invention, respectively. 00), it is a diagram of various aberrations at the time of focusing at infinity in the telephoto end state (f = 290.99).
【図7】(a),(b),(c)はそれぞれ、本発明の第2実施例に係るズームレンズの広角端状態(f=28.80)、中間焦点距離状態(f=100.00)、望遠端状態(f=290.99)における無限遠合焦時に第2補助レンズ群をシフトさせた際のコマ収差図である。 7 (a), (b), and (c) show a wide-angle end state (f = 28.80) and an intermediate focal length state (f = 100.) Of the zoom lens according to the second embodiment of the present invention, respectively. 00), is a coma aberration diagram when the second auxiliary lens group is shifted at the time of infinity focusing in the telephoto end state (f = 290.99).
【図8】本発明の第3実施例に係るズームレンズのレンズ構成を示す図である。 FIG. 8 is a diagram showing a lens configuration of a zoom lens according to a third embodiment of the present invention.
【図9】(a),(b),(c)はそれぞれ、本発明の第3実施例に係るズームレンズの広角端状態(f=28.80)、中間焦点距離状態(f=100.00)、望遠端状態(f=291.00)における無限遠合焦時の諸収差図である。 9 (a), (b), and (c) show a wide-angle end state (f = 28.80) and an intermediate focal length state (f = 100.) Of the zoom lens according to the third embodiment of the present invention, respectively. 00), it is a diagram of various aberrations at the time of focusing at infinity in the telephoto end state (f = 291.00).
【図10】(a),(b),(c)はそれぞれ、本発明の第3実施例に係るズームレンズの広角端状態(f=28.80)、中間焦点距離状態(f=100.00)、望遠端状態(f=291.00)における無限遠合焦時に第2補助レンズ群をシフトさせた際のコマ収差図である。 10 (a), (b), and (c) show a wide-angle end state (f = 28.80) and an intermediate focal length state (f = 100.) Of the zoom lens according to the third embodiment of the present invention, respectively. 00), is a coma aberration diagram when the second auxiliary lens group is shifted at the time of infinity focusing in the telephoto end state (f = 291.00).
【符号の説明】 [Explanation of symbols]
G1:第1レンズ群G2:第2レンズ群G3:第3レンズ群G4:第4レンズ群S :開口絞りI :像面[0001] G1: 1st lens group G2: 2nd lens group G3: 3rd lens group G4: 4th lens group S: Aperture aperture I: Image plane [0001]
BACKGROUND OF THE INVENTION BACKGROUND OF THE Invention
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a zoom lens, and in particular, a high zoom ratio with less change in various aberrations that occur when an image is moved by moving some of the lenses constituting the lens system in a direction substantially perpendicular to the optical axis. Related to zoom lenses. BACKGROUND OF THE tetrahydrofuran 1. Field of the Invention The present invention relates to a zoom lens, and in particular, a high zoom ratio with less change in various aberrations that occur when an image is moved by moving some of the lenses therefore the lens system In a direction substantially perpendicular to the optical axis. Related to zoom lenses.
[0002] [0002]
[Prior art] [Prior art]
Conventionally, so-called image-shiftable optical systems that can move (shift) an image by moving (shifting) some of the lenses constituting the lens system in a direction substantially perpendicular to the optical axis are known. It has been. As such an optical system, there has been proposed a zoom lens capable of shifting an image by shifting a part of the lenses arranged in the zoom lens in a direction substantially perpendicular to the optical axis ( For example, see Patent Document 1). Conventionally, so-called image-shiftable optical systems that can move (shift) an image by moving (shifting) some of the lenses therefore the lens system in a direction substantially perpendicular to the optical axis are known. It has been. As such an optical system, there has been proposed a zoom lens capable of shifting an image by shifting a part of the lenses arranged in the zoom lens in a direction substantially perpendicular to the optical axis (For example, see Patent Document 1).
Hereinafter, in this specification, a lens that shifts in a direction substantially perpendicular to the optical axis is referred to as a shift lens group. Efficiently, in this specification, a lens that shifts in a direction substantially perpendicular to the optical axis is referred to as a shift lens group.
[0003] [0003]
In recent years, zoom lenses are generally used as photographic lenses. When a zoom lens is used as a photographic lens, it is possible to take a picture close to the subject, and there is a user merit that a picture can be taken according to the photographer's intention. For this reason, with the generalization of zoom lenses as photographic lenses, zoom lenses with a high zoom ratio that enable photographing closer to the subject are provided on the market. In recent years, zoom lenses are generally used as photographic lenses. When a zoom lens is used as a photographic lens, it is possible to take a picture close to the subject, and there is a user merit that a picture can be taken according to The photographer's intention. For this reason, with the generalization of zoom lenses as photographic lenses, zoom lenses with a high zoom ratio that enable printing closer to the subject are provided on the market.
As a zoom lens with a high zoom ratio capable of shooting closer to the subject, a positive / negative positive / positive four-group type zoom lens is known (for example, see Patent Document 2). As a zoom lens with a high zoom ratio capable of shooting closer to the subject, a positive / negative positive / positive four-group type zoom lens is known (for example, see Patent Document 2).
A positive, negative, positive, and positive four-group type zoom lens includes, in order from the object side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, and a third lens group having a positive refractive power. And a fourth lens group having a positive refractive power. In this zoom lens, when the lens position changes from the wide-angle end state (shortest focal length) to the telephoto end state (longest focal length), the distance between the first lens group and the second lens group is At least the first lens group and the fourth lens group are on the object side so that the distance between the second lens group and the third lens group decreases and the distance between the third lens group and the fourth lens group decreases. It is the structure which moves to. A positive, negative, positive, and positive four-group type zoom lens includes, in order from the object side, a first lens group having a positive refracting power, a second lens group having a negative refracting power, and a third lens group having And a fourth lens group having a positive refraction power. In this zoom lens, when the lens position changes from the wide-angle end state (shortest focal length) to the telephoto end state (longest focal length), the distance between the first lens group and the second lens group is At least the first lens group and the fourth lens group are on the object side so that the distance between the second lens group and the third lens group decreases and the distance between the third lens group and the fourth lens group decreases. It is the structure which moves to.
[0004] [0004]
Further, with the further generalization of zoom lenses as photographic lenses, zoom lenses that have been reduced in size and weight have been proposed in order to meet user needs for improved portability. Further, with the further generalization of zoom lenses as photographic lenses, zoom lenses that have been reduced in size and weight have been proposed in order to meet user needs for improved portability.
On the other hand, with zoom lenses that are particularly compact and lightweight, the image is not exposed during exposure due to slight camera shake that occurs during shooting, such as camera shake that occurs when the photographer presses the release button. It will blur. Further, when the camera shake amount is constant, the image blur amount increases as the focal length increases, so that the image is significantly deteriorated even by minute camera shake. On the other hand, with zoom lenses that are particularly compact and lightweight, the image is not exposed during exposure due to slight camera shake that occurs during shooting, such as camera shake that occurs when the photographer presses the release button. It will blur. Further, when the camera shake amount is constant, the image blur amount increases as the focal length increases, so that the image is significantly deteriorated even by minute camera shake.
Therefore, there is known a method for correcting image blur caused by camera blur by combining the zoom lens with a drive system, a detection system, and a control system as a zoom lens capable of image shifting. (For example, refer to Patent Document 3). In such a zoom lens, the detection system first detects camera shake. The control system controls the shift lens group by giving a drive amount to the drive system in order to correct the blur detected by the detection system. The drive system drives the shift lens group in a direction substantially perpendicular to the optical axis, and corrects image blur due to camera shake. Therefore, there is known a method for correcting image blur caused by camera blur by combining the zoom lens with a drive system, a detection system, and a control system as a zoom lens capable of image shifting. (For example, refer to Patent Document) 3). In such a zoom lens, the detection system first detects camera shake. The control system controls the shift lens group by giving a drive amount to the drive system in order to correct the blur detected by the detection system. The drive system drives the shift lens group in a direction substantially perpendicular to the optical axis, and corrects image blur due to camera shake.
[0005] [0005]
[Patent Document 1] [Patent Document 1]
Japanese Patent Laid-Open No. 2-81020 [Patent Document 2] Japanese Patent Laid-Open No. 2-81020 [Patent Document 2]
JP 11-142739 A [Patent Document 3] JP 11-142739 A [Patent Document 3]
JP-A-10-282413 [0006] JP-A-10-282413 [0006]
[Problems to be solved by the invention] [Problems to be solved by the invention]
In general, in a zoom lens, it is necessary to correct various aberrations for each lens group in order to obtain predetermined optical performance as a whole zoom lens. Further, the state in which the aberration required for each lens group is corrected (aberration correction state) has a certain range, and generally the range decreases as the zoom ratio increases. In general, in a zoom lens, it is necessary to correct various aberrations for each lens group in order to obtain predetermined optical performance as a whole zoom lens. Further, the state in which the aberration required for each lens group is corrected (aberration correction) state) has a certain range, and generally the range decreases as the zoom ratio increases.
On the other hand, in an optical system capable of image shift, there is an aberration correction state required for the shift lens group alone in order to suppress fluctuations in various aberrations that occur when the image is shifted. On the other hand, in an optical system capable of image shift, there is an aberration correction state required for the shift lens group alone in order to suppress fluctuations in various aberrations that occur when the image is aberrations.
Therefore, the aberration correction state required for the shift lens group in order to obtain good optical performance when the zoom ratio is increased, and the shift to correct various aberration fluctuations that occur when the image is shifted. There is a difference from the aberration correction state required for the lens group. For this reason, there is a problem that it is very difficult to achieve a high zoom ratio and to construct an optical system capable of image shifting. Therefore, the aberration correction state required for the shift lens group in order to obtain good optical performance when the zoom ratio is increased, and the shift to correct various aberration fluctuations that occur when the image is sintered. There is a difference from the aberration correction. state required for the lens group. For this reason, there is a problem that it is very difficult to achieve a high zoom ratio and to construct an optical system capable of image shifting.
[0007] [0007]
The zoom lens disclosed in Patent Document 3 has a large number of lens groups constituting the zoom lens. Therefore, the degree of freedom in selecting the zoom trajectory of each lens group when the lens position changes from the wide-angle end state to the telephoto end state is great. For this reason, high optical performance can be obtained. However, it is difficult to maintain stable optical quality because the driving mechanism for moving the lens group is complicated and the factors causing mutual eccentricity of the lens groups during manufacturing increase. There's a problem. The zoom lens disclosed in Patent Document 3 has a large number of lens groups individually the zoom lens. Therefore, the degree of freedom in selecting the zoom trajectory of each lens group when the lens position changes from the wide-angle end state to the telephoto For this reason, high optical performance can be obtained. However, it is difficult to maintain stable optical quality because the driving mechanism for moving the lens group is complicated and the factors causing mutual eccentricity of the lens groups during manufacturing increase . There's a problem.
[0008] [0008]
Therefore, the present invention has been made in view of the above problems, and is a highly variable image that can move an image by moving some of the lenses constituting the lens system in a direction substantially perpendicular to the optical axis. An object is to provide a zoom lens having a magnification ratio. Therefore, the present invention has been made in view of the above problems, and is a highly variable image that can move an image by moving some of the lenses therefore the lens system in a direction substantially perpendicular to the optical axis. An object is to provide a zoom lens having a efficiency ratio.
[0009] [0009]
[Means for Solving the Problems] [Means for Solving the Problems]
In order to solve the above problems, the present invention In order to solve the above problems, the present invention
In order from the object side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, and a fourth lens having a positive refractive power It consists of a group, In order from the object side, a first lens group having a positive optical power, a second lens group having a negative optical power, a third lens group having a positive optical power, and a fourth lens having a positive optical power It consists of a group,
An aperture stop that moves along the optical axis together with the third lens group is disposed in the third lens group or in the vicinity of the third lens group, An aperture stop that moves along the optical axis together with the third lens group is disposed in the third lens group or in the vicinity of the third lens group,
During zooming from the wide-angle end state to the telephoto end state , the distance between the first lens group and the second lens group increases, and the distance between the second lens group and the third lens group decreases. , At least the first lens group and the fourth lens group move toward the object side so that the distance between the third lens group and the fourth lens group is reduced, During zooming from the wide-angle end state to the telephoto end state , the distance between the first lens group and the second lens group increases, and the distance between the second lens group and the third lens group decreases., At least the first lens group and the fourth lens group move toward the object side so that the distance between the third lens group and the fourth lens group is reduced,
The third lens group includes a first auxiliary lens group, a second auxiliary lens group, and a third auxiliary lens group, the second auxiliary lens group air space on an image side of the first auxiliary lens group The third auxiliary lens group is arranged with an air gap on the image side of the second auxiliary lens group, The third lens group includes a first auxiliary lens group, a second auxiliary lens group, and a third auxiliary lens group, the second auxiliary lens group air space on an image side of the first auxiliary lens group The third auxiliary lens group is arranged with an air gap on the image side of the second auxiliary lens group,
By moving to a direction substantially perpendicular to the optical axis of the second auxiliary lens group, it is possible to move the image, By moving to a direction substantially perpendicular to the optical axis of the second auxiliary lens group, it is possible to move the image,
A zoom lens satisfying the following conditional expression: A zoom lens satisfying the following conditional expression:
0.05 <Ds / fw <0.7 0.05 <Ds / fw <0.7
0.1 <ft / fA <1.5 0.1 <ft / fA <1.5
However, However,
Ds: the distance along the optical axis from the aperture stop to the lens surface closest to the aperture stop among the lens surfaces of the second auxiliary lens group, Ds: the distance along the optical axis from the aperture stop to the lens surface closest to the aperture stop among the lens surfaces of the second auxiliary lens group,
fw: focal length of the entire zoom lens in the wide-angle end state, fw: focal length of the entire zoom lens in the wide-angle end state,
fA: the focal length of all the lenses located on the object side of the second auxiliary lens group in the telephoto end state, fA: the focal length of all the lenses located on the object side of the second auxiliary lens group in the telephoto end state,
ft: focal length of the entire zoom lens in the telephoto end state. ft: focal length of the entire zoom lens in the telephoto end state.
[0010] [0010]
The zoom lens according to the present invention, like the conventional positive, negative, positive, positive four-group type zoom lens, in order from the object side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, A third lens group having a positive refractive power and a fourth lens group having a positive refractive power are included. When the lens position changes from the wide-angle end state to the telephoto end state, the distance between the first lens group and the second lens group increases, and the distance between the second lens group and the third lens group decreases. At least the first lens group and the fourth lens group move to the object side so that the distance between the third lens group and the fourth lens group decreases. The zoom lens according to the present invention, like the conventional positive, negative, positive, positive four-group type zoom lens, in order from the object side, a first lens group having a positive optical power, a second lens group having a negative When the lens position changes from the wide-angle end state to the telephoto end state, the distance between the first lens group. When the lens position changes from the wide-angle end state to the telephoto end state, the distance between the first lens group. And the second lens group increases, and the distance between the second lens group and the third lens group decreases. At least the first lens group and the fourth lens group move to the object side so that the distance between the third lens group and the fourth lens group decreases.
In a zoom lens with a high zoom ratio, it is desirable to arrange the aperture stop near the center of the lens system in order to satisfactorily correct fluctuations in off-axis aberrations accompanying changes in the lens position state. Therefore, in the zoom lens according to the present invention, the aperture stop is disposed in the vicinity of the third lens group or inside the third lens group . In a zoom lens with a high zoom ratio, it is desirable to arrange the aperture stop near the center of the lens system in order to satisfactorily correct fluctuations in off-axis aberrations accompanying changes in the lens position state. Therefore, in the zoom lens according to the present invention, the aperture stop is disposed in the vicinity of the third lens group or inside the third lens group .
[0011] [0011]
Under the above lens configuration, the zoom lens according to the present invention has a configuration that satisfies the following conditions (A), (B), and (C), thereby favorably correcting variations in various aberrations that occur during image shift. Can do. Under the above lens configuration, the zoom lens according to the present invention has a configuration that satisfies the following conditions (A), (B), and (C), thereby favorably correcting variations in various aberrations that occur during image shift. Can do ..
(A) The third lens group is composed of three auxiliary lens groups of a first auxiliary lens group, a second auxiliary lens group, and a third auxiliary lens group in order from the object side, and the second auxiliary lens group with respect to the optical axis. The image is shifted by shifting in a substantially vertical direction (the second auxiliary lens group is a shift lens group). (A) The third lens group is composed of three auxiliary lens groups of a first auxiliary lens group, a second auxiliary lens group, and a third auxiliary lens group in order from the object side, and the second auxiliary lens group with respect to the optical axis. The image is moving by shifting in a substantially vertical direction (the second auxiliary lens group is a shift lens group).
(B) The distance between the second auxiliary lens group and the aperture stop is set appropriately. (B) The distance between the second auxiliary lens group and the aperture stop is set appropriately.
(C) The focal length by all the lenses located on the object side with respect to the second auxiliary lens group is appropriately set. (C) The focal length by all the lenses located on the object side with respect to the second auxiliary lens group is appropriately set.
[0012] [0012]
Condition (A) is a condition for satisfactorily correcting variations in various aberrations accompanying changes in the lens position state and variations in various aberrations that occur during image shift. Condition (A) is a condition for satisfactorily correcting variations in various aberrations accompanying changes in the lens position state and variations in various aberrations that occur during image shift.
In the zoom lens according to the present invention, the third lens group as a whole corrects the fluctuations of various aberrations accompanying the change of the lens position state, and the second auxiliary lens group (shift lens group) changes the various aberrations generated when the image is shifted. A function for aberration correction is divided so as to correct well. As a result, it is possible to satisfactorily correct variations in various aberrations accompanying changes in the lens position state, and at the same time, to properly correct variations in various aberrations that occur during image shift. In the zoom lens according to the present invention, the third lens group as a whole corrects the fluctuations of various aberrations accompanying the change of the lens position state, and the second auxiliary lens group (shift lens group) changes the various aberrations generated when the A function for aberration correction is divided so as to correct well. As a result, it is possible to satisfactorily correct variations in various aberrations accompanying changes in the lens position state, and at the same time, to properly correct variations in various aberrations that occur during image shift.
[0013] [0013]
Condition (B) is a condition for satisfactorily correcting fluctuations in off-axis aberrations that occur during image shift. Condition (B) is a condition for satisfactorily correcting fluctuations in off-axis aberrations that occur during image shift.
Generally, an off-axis light beam incident on a lens group disposed near the aperture stop passes near the center of the lens group. On the other hand, the off-axis light beam incident on the lens group disposed away from the aperture stop passes through the lens group away from the optical axis. Generally, an off-axis light beam incident on a lens group disposed near the aperture stop passes near the center of the lens group. On the other hand, the off-axis light beam incident on the lens group disposed away from the aperture stop passes through the lens group away from the optical axis.
The lens surface of each lens has a circular shape with the optical axis as the center of rotation. For this reason, when the shift lens group is shifted in a direction substantially perpendicular to the optical axis, the refractive power in the shifted direction and the refractive power in the opposite direction change in opposite directions. That is, of the lens surfaces of the shift lens group, light incident on the lens surface on the shifted direction side is refracted so as to approach the optical axis, and light incident on the lens surface on the opposite side to the shifted direction is optical axis. Refracted away from. For this reason, fluctuations in off-axis aberrations are likely to occur. The lens surface of each lens has a circular shape with the optical axis as the center of rotation. For this reason, when the shift lens group is oblique in a direction substantially refractive to the optical axis, the refractive power in the attributable direction and the That is, of the lens surfaces of the shift lens group, light incident on the lens surface on the attributable direction side is refracted so as to approach the optical axis, and light incident on the Lens surface on the opposite side to the rotating direction is optical axis. Refracted away from. For this reason, fluctuations in off-axis aberrations are likely to occur.
[0014] [0014]
The condition (C) is a condition for satisfactorily correcting the fluctuation of the axial aberration that occurs during the image shift. The condition (C) is a condition for satisfactorily correcting the fluctuation of the axial aberration that occurs during the image shift.
When the off-axis light beam incident on the second auxiliary lens group is close to a parallel state, the image position of the light beam incident on the lens system in a state parallel to the optical axis is shifted in accordance with the shift of the second auxiliary lens group. However, there is little variation in aberrations. When the off-axis light beam incident on the second auxiliary lens group is close to a parallel state, the image position of the light beam incident on the lens system in a state parallel to the optical axis is defined in accordance with the shift of the second auxiliary lens group. However, there is little variation in aberrations.
Further, when the focal length of all the lenses located on the object side of the second auxiliary lens group is negative, the axial light beam spreads and enters the second auxiliary lens group, so that the spherical aberration is sufficiently corrected. I can't. Further, when the focal length of all the lenses located on the object side of the second auxiliary lens group is negative, the axial light beam spreads and enters the second auxiliary lens group, so that the spherical aberration is sufficiently corrected. I can't ..
Therefore, when all the lenses located closer to the object side than the second auxiliary lens group have a positive refractive power as a whole, and the positive refractive power is not so large, the fluctuation of the on-axis aberration is corrected well. be able to. Therefore, when all the lenses located closer to the object side than the second auxiliary lens group have a positive refracting power as a whole, and the positive refracting power is not so large, the fluctuation of the on-axis aberration is corrected well. able to.
[0015] [0015]
Next, each conditional expression will be described in detail. Next, each conditional expression will be described in detail.
The following conditional expression (1) is a conditional expression that specifically defines the condition (B) numerically, and the distance from the aperture stop in the wide-angle end state to the second auxiliary lens group disposed in the third lens group Is a conditional expression that prescribes The following conditional expression (1) is a conditional expression that specifically defines the condition (B) numerically, and the distance from the aperture stop in the wide-angle end state to the second auxiliary lens group disposed in the third lens group Is a conditional expression that prescribes
(1) 0.05 <Ds / fw <0.7 (1) 0.05 <Ds / fw <0.7
However, However,
Ds: the distance along the optical axis from the aperture stop to the lens surface closest to the aperture stop among the lens surfaces of the second auxiliary lens unit, Ds: the distance along the optical axis from the aperture stop to the lens surface closest to the aperture stop among the lens surfaces of the second auxiliary lens unit,
fw: focal length of the entire zoom lens in the wide-angle end state. fw: focal length of the entire zoom lens in the wide-angle end state.
[0016] [0016]
If the upper limit of conditional expression (1) is exceeded, the off-axis light beam incident on the shift lens group in the wide-angle end state will be greatly separated from the optical axis. For this reason, fluctuations in off-axis aberrations that occur during image shift cannot be corrected satisfactorily. If the upper limit of conditional expression (1) is exceeded, the off-axis light beam incident on the shift lens group in the wide-angle end state will be greatly separated from the optical axis. For this reason, fluctuations in off-axis aberrations that occur during image shift cannot be corrected satisfactorily.
On the other hand, if the lower limit value of conditional expression (1) is not reached, sufficient space cannot be provided between the shift lens group and the aperture stop, and the aperture blade and the shift are shifted when the aperture is small (when the aperture is reduced small). Interference with the lens group occurs. Alternatively, the tolerance of each component may cause the shift lens group to touch the diaphragm member during manufacturing. On the other hand, if the lower limit value of conditional expression (1) is not reached, sufficient space cannot be provided between the shift lens group and the aperture stop, and the aperture blade and the shift are correlated when the aperture is small ( When the aperture is reduced small). Interference with the lens group occurs. Alternatively, the tolerance of each component may cause the shift lens group to touch the diaphragm member during manufacturing.
[0017] [0017]
Conditional expression (2) is a conditional expression that specifically defines the condition (C) numerically. Conditional expression (2) is a conditional expression that specifically defines the condition (C) numerically.
(2) 0.1 <ft / fA <1.5 (2) 0.1 <ft / fA <1.5
However, However,
fA: focal length of all lenses located on the object side of the second auxiliary lens group in the telephoto end state, fA: focal length of all lenses located on the object side of the second auxiliary lens group in the telephoto end state,
ft: focal length of the entire zoom lens in the telephoto end state. ft: focal length of the entire zoom lens in the telephoto end state.
[0018] [0018]
When the upper limit of conditional expression (2) is exceeded, the axial light beam is largely converged and enters the second auxiliary lens group. For this reason, the fluctuation of the axial aberration that occurs during the image shift becomes very large. When the upper limit of conditional expression (2) is exceeded, the axial light beam is largely converged and enters the second auxiliary lens group. For this reason, the fluctuation of the axial aberration that occurs during the image shift becomes very large.
On the other hand, if the lower limit of conditional expression (2) is not reached, the axial light beam spreads and enters the second auxiliary lens group. For this reason, it is impossible to sufficiently correct the axial aberration. On the other hand, if the lower limit of conditional expression (2) is not reached, the axial light beam spreads and enters the second auxiliary lens group. For this reason, it is impossible to sufficiently correct the axial aberration.
The lens diameter of the second auxiliary lens group is directly related to the size of the drive system for shifting the second auxiliary lens group in a direction substantially perpendicular to the optical axis. Therefore, in order to reduce the lens diameter of the second auxiliary lens unit and improve portability, it is desirable to set the lower limit of conditional expression (2) to 0.15. The lens diameter of the second auxiliary lens group is directly related to the size of the drive system for shifting the second auxiliary lens group in a direction substantially perpendicular to the optical axis. Therefore, in order to reduce the lens diameter of the second auxiliary lens unit and improve portability, it is desirable to set the lower limit of conditional expression (2) to 0.15.
[0019] [0019]
Under the above-described configuration, the zoom lens according to the present invention is configured such that each auxiliary lens group constituting the third lens group satisfies the following conditions (D), (E), and (F). It is possible to more favorably correct for variations in various aberrations that occur during downsizing and image shift. Under the above-described configuration, the zoom lens according to the present invention is configured such that each auxiliary lens group therefore the third lens group satisfies the following conditions (D), (E), and (F). It is possible to more favorably correct for variations in various aberrations that occur during downsizing and image shift.
(D) The refractive power of the first auxiliary lens group is positive, and the focal length is set appropriately. (D) The refracting power of the first auxiliary lens group is positive, and the focal length is set appropriately.
(E) The refractive power of the second auxiliary lens group is positive, and the shape thereof is set appropriately. (E) The refracting power of the second auxiliary lens group is positive, and the shape thereof is set appropriately.
(F) The refractive power of the third auxiliary lens unit is negative. (F) The refracting power of the third auxiliary lens unit is negative.
[0020] [0020]
The condition (D) is a condition for reducing the size in the telephoto end state and correcting aberrations more favorably at the center of the screen. The condition (D) is a condition for reducing the size in the telephoto end state and correcting aberrations more favorably at the center of the screen.
The zoom lens according to the present invention is negative in the combined refractive power of the first lens group and the second lens group, similarly to the conventional positive, negative, positive and positive four-group type zoom lens. Therefore, in order to satisfy the above condition (C), the zoom lens according to the present invention is configured such that the first auxiliary lens group located between the second lens group and the second auxiliary lens group has a positive refractive power. . The zoom lens according to the present invention is negative in the combined refracting power of the first lens group and the second lens group, similarly to the conventional positive, negative, positive and positive four-group type zoom lens. Therefore, in order to satisfy the above condition (C), the zoom lens according to the present invention is configured such that the first auxiliary lens group located between the second lens group and the second auxiliary lens group has a positive refraction power.
Here, in order to reduce the size, it is effective to increase the refractive power of the first auxiliary lens group. However, if the refractive power of the first auxiliary lens unit is too large, the negative spherical aberration cannot be sufficiently corrected in the telephoto end state. Here, in order to reduce the size, it is effective to increase the refracting power of the first auxiliary lens group. However, if the refracting power of the first auxiliary lens unit is too large, the negative spherical aberration cannot be sufficiently corrected in the telephoto end state.
[0021] [0021]
Therefore, it is desirable that the zoom lens according to the present invention satisfies the following conditional expression (3). Therefore, it is desirable that the zoom lens according to the present invention satisfies the following conditional expression (3).
(3) 0.06 <fa / ft <0.2 (3) 0.06 <fa / ft <0.2
However, However,
fa: focal length of the first auxiliary lens group, fa: focal length of the first auxiliary lens group,
ft: focal length of the entire zoom lens in the telephoto end state. ft: focal length of the entire zoom lens in the telephoto end state.
[0022] [0022]
Conditional expression (3) is a conditional expression that defines the focal length of the first auxiliary lens group. Conditional expression (3) is a conditional expression that defines the focal length of the first auxiliary lens group.
If the upper limit of conditional expression (3) is exceeded, the overall length of the zoom lens in the telephoto end state will be increased. If the upper limit of conditional expression (3) is exceeded, the overall length of the zoom lens in the telephoto end state will be increased.
On the other hand, if the lower limit value of conditional expression (3) is not reached, negative spherical aberration that occurs in the telephoto end state cannot be corrected satisfactorily. On the other hand, if the lower limit value of conditional expression (3) is not reached, negative spherical aberration that occurs in the telephoto end state cannot be corrected satisfactorily.
[0023] [0023]
Condition (E) is a condition for satisfactorily correcting decentering coma generated in the center of the screen by the shift lens group alone during image shift. Condition (E) is a condition for satisfactorily correcting decentering coma generated in the center of the screen by the shift lens group alone during image shift.
In general, the shift lens group can shift an image regardless of whether it has a positive refractive power or a negative refractive power. In the zoom lens according to the present invention, since the angle of view in the wide-angle end state is large, when the shift lens group has a negative refractive power, the luminous flux is diverged. For this reason, not only enlargement of the lens diameter is caused but also off-axis light beam directed toward the periphery of the screen passes through the periphery of the lens, resulting in a great amount of coma aberration. Therefore, in the zoom lens according to the present invention, the second auxiliary lens group that is the shift lens group has a positive refractive power. In general, the shift lens group can shift an image regardless of whether it has a positive refracting power or a negative refracting power. In the zoom lens according to the present invention, since the angle of view in the wide-angle end state is large For this reason, not only enlargement of the lens diameter is caused but also off-axis light beam directed toward the parity of the screen passes through the parity of, when the shift lens group has a negative optical power, the luminous flux is diverged. The lens, resulting in a great amount of coma aberration. Therefore, in the zoom lens according to the present invention, the second auxiliary lens group that is the shift lens group has a positive refractive power.
In addition, it is desirable to appropriately set the shape of the shift lens group in order to satisfactorily correct decentration coma generated in the center of the screen by the shift lens group alone during image shift. For this purpose, it is necessary to make a configuration satisfying the sine condition in addition to correcting spherical aberration generated by the shift lens group alone. In addition, it is desirable to appropriately set the shape of the shift lens group in order to satisfactorily correct decentration coma generated in the center of the screen by the shift lens group alone during image shift. For this purpose, it is necessary to make a configuration satisfying the sine condition in addition to correcting spherical aberration generated by the shift lens group alone.
[0024] [0024]
Therefore, in the zoom lens according to the present invention, it is desirable that the second auxiliary lens group has at least one positive lens and one negative lens, and satisfies the following conditional expression (4). Therefore, in the zoom lens according to the present invention, it is desirable that the second auxiliary lens group has at least one positive lens and one negative lens, and satisfies the following conditional expression (4).
(4) -0.6 <(na / ra) / (nb / rb) <0 (4) -0.6 <(na / ra) / (nb / rb) <0
However, However,
ra: radius of curvature of the lens surface closest to the object in the second auxiliary lens group, ra: radius of curvature of the lens surface closest to the object in the second auxiliary lens group,
na: refractive index with respect to d-line of the lens closest to the object side in the second auxiliary lens group, na: refractive index with respect to d-line of the lens closest to the object side in the second auxiliary lens group,
rb: radius of curvature of the lens surface closest to the image side in the second auxiliary lens unit, rb: radius of curvature of the lens surface closest to the image side in the second auxiliary lens unit,
nb: Refractive index with respect to d-line of the most image side lens in the second auxiliary lens unit. nb: Refractive index with respect to d-line of the most image side lens in the second auxiliary lens unit.
[0025] [0025]
Conditional expression (4) is a conditional expression that appropriately defines the shape of the second auxiliary lens group, and is a condition for satisfactorily correcting the decentering coma generated in the center of the screen by the shift lens group alone during image shift. It is a formula. As described above, the zoom lens according to the present invention corrects the spherical aberration generated by the shift lens group alone and simultaneously satisfies the sine condition. Conditional expression (4) is a conditional expression that appropriately defines the shape of the second auxiliary lens group, and is a condition for satisfactorily correcting the decentering coma generated in the center of the screen by the shift lens group alone during image shift. It is a formula. As described above, the zoom lens according to the present invention corrects the spherical aberration generated by the shift lens group alone and simultaneously satisfies the sine condition.
If the upper limit value of conditional expression (4) is exceeded, the sine condition will be greatly negative, and inward coma will occur greatly at the center of the screen during image shift. If the upper limit value of conditional expression (4) is exceeded, the sine condition will be greatly negative, and inward coma will occur greatly at the center of the screen during image shift.
On the other hand, if the lower limit value of the conditional expression (4) is not reached, the sine condition is greatly increased and large outward coma occurs at the center of the screen during image shift. On the other hand, if the lower limit value of the conditional expression (4) is not reached, the sine condition is greatly increased and large outward coma occurs at the center of the screen during image shift.
[0026] [0026]
In the zoom lens according to the present invention, the aberration correction function of each lens group is clarified to satisfactorily correct variations in various aberrations accompanying changes in the focal length state. In the zoom lens according to the present invention, the aberration correction function of each lens group is clarified to satisfactorily correct variations in various aberrations accompanying changes in the focal length state.
In the zoom lens according to the present invention, in the wide-angle end state, the distance between the first lens group and the second lens group is made as small as possible, and the distance between the second lens group and the aperture stop is increased to some extent. Thereby, the off-axis light beam passing through the first lens group is brought close to the optical axis, and the off-axis light beam passing through the second lens group is separated from the optical axis. In the zoom lens according to the present invention, in the wide-angle end state, the distance between the first lens group and the second lens group is made as small as possible, and the distance between the second lens group and the aperture stop is increased to some extent. Thus, the off-axis light beam passing through the first lens group is brought close to the optical axis, and the off-axis light beam passing through the second lens group is separated from the optical axis.
The zoom lens according to the present invention increases the distance between the first lens group and the second lens group when the lens position changes from the wide-angle end state to the telephoto end state, and the second lens group and the aperture stop. The first lens group and the second lens group are moved so as to reduce the distance between the first lens group and the second lens group. Thereby, the off-axis light beam passing through the first lens group is separated from the optical axis, and the off-axis light beam passing through the second lens group is brought close to the optical axis. The zoom lens according to the present invention increases the distance between the first lens group and the second lens group when the lens position changes from the wide-angle end state to the telephoto end state, and the second lens group and the aperture stop. First lens group and the second lens group are moved so as to reduce the distance between the first lens group and the second lens group. Thus, the off-axis light beam passing through the first lens group is separated from the optical axis, and the off-axis light beam passing through the second lens group is brought close to the optical axis.
As described above, in the zoom lens according to the present invention, by changing the height of the off-axis light beam that passes through the first lens group and the second lens group, the fluctuation of the off-axis aberration caused by the change in the lens position state is reduced. Corrected well. As described above, in the zoom lens according to the present invention, by changing the height of the off-axis light beam that passes through the first lens group and the second lens group, the fluctuation of the off-axis aberration caused by the change in the lens position state is reduced. Corrected well.
[0027] [0027]
Furthermore, the zoom lens according to the present invention is configured to increase the distance between the third lens group and the fourth lens group in the wide-angle end state. Thereby, the off-axis light beam passing through the fourth lens group is separated from the optical axis. Furthermore, the zoom lens according to the present invention is configured to increase the distance between the third lens group and the fourth lens group in the wide-angle end state. Thus, the off-axis light beam passing through the fourth lens group is separated. from the optical axis.
In addition, the zoom lens according to the present invention is configured to reduce the distance between the third lens group and the fourth lens group when the lens position changes from the wide-angle end state to the telephoto end state. Thus, the off-axis light beam passing through the fourth lens group is changed so as to approach the optical axis, and the fluctuation of off-axis aberration caused by the change in the lens position state is corrected more favorably. In addition, the zoom lens according to the present invention is configured to reduce the distance between the third lens group and the fourth lens group when the lens position changes from the wide-angle end state to the telephoto end state. Thus, the off- axis light beam passing through the fourth lens group is changed so as to approach the optical axis, and the fluctuation of off-axis aberration caused by the change in the lens position state is corrected more favorably.
[0028] [0028]
As described above, the zoom lens according to the present invention mainly corrects off-axis aberrations that occur when the first lens group is in the telephoto end state, and mainly corrects off-axis aberrations that occur when the second lens group is in the wide-angle end state. The fourth lens group is also configured to mainly correct off-axis aberrations that occur in the wide-angle end state. Since the second lens group and the fourth lens group are arranged on the object side and the image side, respectively, with an aperture stop, they have different roles in correcting aberrations. As described above, the zoom lens according to the present invention mainly corrects off-axis aberrations that occur when the first lens group is in the telephoto end state, and mainly corrects off-axis aberrations that occur when the second lens group is in the wide -angle end state. The fourth lens group is also configured to mainly correct off-axis aberrations that occur in the wide-angle end state. Since the second lens group and the fourth lens group are arranged on the object side and the image side, respectively, with an aperture stop, they have different roles in correcting aberrations.
In the zoom lens according to the present invention, the aperture stop is disposed in the vicinity of the third lens group or in the third lens group , and the off-axis light beam passes near the optical axis of the third lens group, so that the off-axis aberration is reduced. Less likely to occur. For this reason, the third lens group mainly corrects axial aberration. In the zoom lens according to the present invention, the aperture stop is disposed in the vicinity of the third lens group or in the third lens group , and the off-axis light beam passes near the optical axis of the third lens group, so that The off-axis aberration is reduced. Less likely to occur. For this reason, the third lens group mainly corrects axial aberration.
The zoom lens according to the present invention is configured so that the axial light beam emitted from the third lens group is close to parallel light. As a result, it is possible to change only the off-axis aberration without changing the on-axis aberration due to the change in the distance between the third lens group and the fourth lens group, and the image plane generated with the change in the lens position state. The fluctuation of curvature is corrected well. The zoom lens according to the present invention is configured so that the axial light beam emitted from the third lens group is close to parallel light. As a result, it is possible to change only the off-axis aberration without changing the on-axis aberration Due to the change in the distance between the third lens group and the fourth lens group, and the image plane generated with the change in the lens position state. The fluctuation of curvature is corrected well.
[0029] [0029]
Condition (F) is a condition for bringing the off-axis light beam emitted from the third lens group close to parallel light. Condition (F) is a condition for bringing the off-axis light beam emitted from the third lens group close to parallel light.
In the zoom lens according to the present invention, the first auxiliary lens group and the second auxiliary lens in the third lens group have positive refractive power, and the off-axis light beam emitted from the third lens group is made to approach parallel light. Therefore, it is desirable that the third auxiliary lens group has a negative refractive power. In the zoom lens according to the present invention, the first auxiliary lens group and the second auxiliary lens in the third lens group have positive refracting power, and the off-axis light beam emitted from the third lens group is made to approach parallel light. Therefore, it is desirable that the third auxiliary lens group has a negative refracting power.
[0030] [0030]
In particular, it is desirable that the zoom lens according to the present invention satisfies the following conditional expression (5). In particular, it is desirable that the zoom lens according to the present invention satisfies the following conditional expression (5).
(5) 0.5 <| fc | / f3 <0.9 (5) 0.5 <| fc | / f3 <0.9
However, However,
fc: focal length of the third auxiliary lens group, fc: focal length of the third auxiliary lens group,
f3: focal length of the third lens unit. f3: focal length of the third lens unit.
[0031] [0031]
Conditional expression (5) is a conditional expression that appropriately defines the focal length of the third auxiliary lens group in order to realize higher optical performance of the zoom lens according to the present invention. Conditional expression (5) is a conditional expression that appropriately defines the focal length of the third auxiliary lens group in order to realize higher optical performance of the zoom lens according to the present invention.
If the upper limit value of conditional expression (5) is exceeded, negative distortion in the wide-angle end state cannot be corrected more satisfactorily. If the upper limit value of conditional expression (5) is exceeded, negative distortion in the wide-angle end state cannot be corrected more satisfactorily.
If the lower limit of conditional expression (5) is not reached, the positive spherical aberration occurring in the third auxiliary lens group cannot be corrected more satisfactorily. If the lower limit of conditional expression (5) is not reached, the positive spherical aberration occurring in the third auxiliary lens group cannot be corrected more satisfactorily.
[0032] [0032]
In the zoom lens according to the present invention, it is preferable that the third auxiliary lens unit has a negative lens having a concave surface facing the object side closest to the object side, and satisfies the following conditional expression (6). In the zoom lens according to the present invention, it is preferred that the third auxiliary lens unit has a negative lens having a concave surface facing the object side closest to the object side, and satisfies the following conditional expression (6).
(6) 0.5 <| rc | / f3 <0.75 (6) 0.5 <| rc | / f3 <0.75
However, However,
rc: radius of curvature of the object-side lens surface of the negative lens disposed closest to the object side in the third auxiliary lens unit, rc: radius of curvature of the object-side lens surface of the negative lens disposed closest to the object side in the third auxiliary lens unit,
f3: focal length of the third lens unit. f3: focal length of the third lens unit.
[0033] [0033]
Conditional expression (6) is a conditional expression for performing better correction of fluctuations in various aberrations that occur during image shift, and is provided on the object side of the negative lens arranged closest to the object side in the third auxiliary lens group. It is a conditional expression that defines the radius of curvature of the lens surface. Conditional expression (6) is a conditional expression for performing better correction of fluctuations in various aberrations that occur during image shift, and is provided on the object side of the negative lens arranged closest to the object side in the third auxiliary lens group. It is a conditional expression that defines the radius of curvature of the lens surface.
If the upper limit value of conditional expression (6) is exceeded, the performance deterioration of the peripheral portion of the screen becomes large in the wide-angle end state during image shift. If the upper limit value of conditional expression (6) is exceeded, the performance deterioration of the peripheral portion of the screen becomes large in the wide-angle end state during image shift.
On the other hand, if the lower limit value of conditional expression (6) is not reached, performance degradation at the center of the screen becomes large in the telephoto end state during image shift. On the other hand, if the lower limit value of conditional expression (6) is not reached, performance degradation at the center of the screen becomes large in the telephoto end state during image shift.
[0034] [0034]
The zoom lens according to the present invention can achieve higher optical performance by appropriately arranging an aspheric lens. The zoom lens according to the present invention can achieve higher optical performance by appropriately arranging an aspheric lens.
In order to improve the optical performance in the center of the screen regardless of the lens position, it is desirable that one lens surface in the first auxiliary lens group in the third lens group be an aspherical surface. In order to improve the optical performance in the center of the screen regardless of the lens position, it is desirable that one lens surface in the first auxiliary lens group in the third lens group be an aspherical surface.
In order to correct the coma variation due to the change in the angle of view in the wide-angle end state, it is desirable that at least one lens surface in the second lens group or the fourth lens group is an aspherical surface. Further, it is possible to further improve the performance by arranging aspherical lenses in both the second lens group and the fourth lens group. In order to correct the coma variation due to the change in the angle of view in the wide-angle end state, it is desirable that at least one lens surface in the second lens group or the fourth lens group is an aspherical surface. Further, it is possible to further improve the performance by arranging aspherical lenses in both the second lens group and the fourth lens group.
[0035] [0035]
In the zoom lens according to the present invention, it is suitable that the second lens group is moved in the optical axis direction when focusing on a short distance in order to suppress fluctuations in various aberrations. In the zoom lens according to the present invention, it is suitable that the second lens group is moved in the optical axis direction when focusing on a short distance in order to suppress fluctuations in various aberrations.
The present invention is not limited to a zoom lens, and can be applied to a so-called varifocal zoom lens in which the focal length state does not exist continuously, for example. The present invention is not limited to a zoom lens, and can be applied to a so-called varifocal zoom lens in which the focal length state does not exist continuously, for example.
Furthermore, the zoom lens according to the present invention is applied to an optical system in which an additional lens is arranged on the image side of the fourth lens group to move the exit pupil position away from the image plane position, and a photoelectric conversion element such as a CCD is used as a light receiving element. It is also possible to do. This is because when the photoelectric conversion element is used as the light receiving element, the exit pupil position needs to be away from the image plane position in order to arrange the microlens array immediately before the element surface. Note that when the amount of received light is small, noise is likely to occur, and there is a problem that exposure cannot be performed in a short time. Therefore, the microlens array is arranged for the purpose of increasing the amount of received light. Furthermore, the zoom lens according to the present invention is applied to an optical system in which an additional lens is arranged on the image side of the fourth lens group to move the exit pupil position away from the image plane position, and a photoelectric conversion element Such as a CCD is used as a light receiving element. It is also possible to do. This is because when the photoelectric conversion element is used as the light receiving element, the exit pupil position needs to be away from the image plane position in order To arrange the microlens array immediately before the element surface. Note that when the amount of received light is small, noise is likely to occur, and there is a problem that exposure cannot be performed in a short time. Therefore, the microlens array is arranged. for the purpose of increasing the amount of received light.
[0036] [0036]
【Example】 [Example]
Hereinafter, zoom lenses according to embodiments of the present invention will be described with reference to the accompanying drawings. Embodied, zoom lenses according to embodiments of the present invention will be described with reference to the accompanying drawings.
In each embodiment, the aspheric shape is represented by the following aspheric expression. Here, y is the height from the optical axis, x is the sag amount, c is the reference curvature (paraxial curvature), κ is the conic constant, and C 4 , C 6 , C 8 and C 10 are 4, 6, 8, respectively. A 10th-order aspheric coefficient is used. In each embodiment, the aspheric shape is represented by the following aspheric expression. Here, y is the height from the optical axis, x is the sag amount, c is the reference curvature (paraxial curvature), κ is the conic constant, and C 4 , C 6 , C 8 and C 10 are 4, 6, 8, respectively. A 10th-order aspheric coefficient is used.
[0037] [0037]
[Expression 1] [Expression 1]
x = cy 2 / {1+ (1-κc 2 y 2 ) 1/2 } + C 4 y 4 + C 6 y 6 + C 8 y 8 + C 10 y 10 x = cy 2 / {1+ (1-κc 2 y 2 ) 1/2 } + C 4 y 4 + C 6 y 6 + C 8 y 8 + C 10 y 10
[0038] [0038]
FIG. 1 is a diagram showing refractive power distribution of a variable focal length lens system (zoom lens) according to each embodiment of the present invention. FIG. 1 is a diagram showing optical power distribution of a variable focal length lens system (zoom lens) according to each embodiment of the present invention.
The zoom lens according to each embodiment of the present invention includes, in order from the object side, a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, and a first lens group having a positive refractive power. The third lens group G3 includes a third lens group G3 and a fourth lens group G4 having a positive refractive power. When zooming from the wide-angle end state (W) to the telephoto end state (T), the air gap between the first lens group G1 and the second lens group G2 increases, and the second lens group G2 and the third lens group. At least the first lens group G1 and the fourth lens group G4 move to the object side so that the air gap with G3 decreases and the air gap between the third lens group G3 and the fourth lens group G4 decreases. The zoom lens according to each embodiment of the present invention includes, in order from the object side, a first lens group G1 having a positive refracting power, a second lens group G2 having a negative refractive power, and a first lens group having a positive The third lens group G3 includes a third lens group G3 and a fourth lens group G4 having a positive refraction power. When zooming from the wide-angle end state (W) to the telephoto end state (T), the air gap between the first lens group G1 and the second lens group G2 increases, and the second lens group G2 and the third lens group. At least the first lens group G1 and the fourth lens group G4 move to the object side so that the air gap with G3 decreases and the air gap between the third lens group G3 and the fourth lens group G4 decreases.
[0039] [0039]
(First embodiment) (First embodiment)
FIG. 2 is a diagram showing a lens configuration of the zoom lens according to the first example of the present invention. FIG. 2 is a diagram showing a lens configuration of the zoom lens according to the first example of the present invention.
In the zoom lens according to the present embodiment, the first lens group G1 includes, in order from the object side, a cemented lens L11 of a meniscus negative lens having a convex surface facing the object side and a positive lens having a convex surface facing the object side, And a meniscus-shaped positive lens L12 having a convex surface on the side. In the zoom lens according to the present embodiment, the first lens group G1 includes, in order from the object side, a cemented lens L11 of a meniscus negative lens having a convex surface facing the object side and a positive lens having a convex surface facing the object side, And a meniscus-shaped positive lens L12 having a convex surface on the side.
The second lens group G2, in order from the object side, includes a negative lens L21 having a concave surface directed toward the image side, a negative lens L22 having a concave surface directed toward the object side, a positive lens L23 having a convex surface directed toward the object side, and an object side And a negative lens L24 having a concave surface on the surface. The second lens group G2, in order from the object side, includes a negative lens L21 having a concave surface directed toward the image side, a negative lens L22 having a concave surface directed toward the object side, a positive lens L23 having a convex surface directed toward the object side, and an object side And a negative lens L24 having a concave surface on the surface.
The third lens group G3 has, in order from the object side, a cemented positive lens L31 including a biconvex positive lens and a negative lens having a concave surface facing the object side, and a concave surface facing the biconvex positive lens and the object side. It consists of a cemented positive lens L32 with a negative lens, and a negative lens L33 with a concave surface facing the object side. The third lens group G3 has, in order from the object side, a cemented positive lens L31 including a biconvex positive lens and a negative lens having a concave surface facing the object side, and a concave surface facing the biconvex positive lens and the object side It consists of a cemented positive lens L32 with a negative lens, and a negative lens L33 with a concave surface facing the object side.
The fourth lens group G4 includes, in order from the object side, a positive lens L41 having a convex surface directed toward the image side, and a cemented lens L42 including a biconvex positive lens and a negative lens having a concave surface directed toward the object side. Yes. The fourth lens group G4 includes, in order from the object side, a positive lens L41 having a convex surface directed toward the image side, and a cemented lens L42 including a biconvex positive lens and a negative lens having a concave surface directed toward the object side. Yes.
[0040] [0040]
In the zoom lens according to the present embodiment, the aperture stop S is disposed on the object side of the third lens group G3, and moves together with the third lens group G3 when the lens position state changes. In the zoom lens according to the present embodiment, the aperture stop S is disposed on the object side of the third lens group G3, and moves together with the third lens group G3 when the lens position state changes.
Further, the negative lens L21 in the second lens group G2 includes an aspheric thin plastic resin layer on the object side lens surface. Further, the negative lens L21 in the second lens group G2 includes an aspheric thin plastic resin layer on the object side lens surface.
In the zoom lens according to the present embodiment, the cemented positive lens L31 in the third lens group G3 is a first auxiliary lens group, the cemented positive lens L32 is a second auxiliary lens group, and the negative lens L33 is a third auxiliary lens group. Each of these functions. In the zoom lens according to the present embodiment, the cemented positive lens L31 in the third lens group G3 is a first auxiliary lens group, the cemented positive lens L32 is a second auxiliary lens group, and the negative lens L33 is a third auxiliary lens group. Each of these functions.
[0041] [0041]
Table 1 below lists values of specifications of the zoom lens according to the first example of the present invention. Table 1 below lists values ​​of specifications of the zoom lens according to the first example of the present invention.
In (Overall specifications), f represents a focal length, FNO represents an F number, and 2ω represents an angle of view (unit: degree). In (Overall specifications), f represents a focal length, FNO represents an F number, and 2ω represents an angle of view (unit: degree).
In (lens data), the surface indicates the order of the lens surfaces from the object side, and the interval indicates the interval of the lens surfaces. The refractive index is a value with respect to the d-line (λ = 587.6 nm). Further, a radius of curvature of 0.0000 indicates a plane, and Bf indicates a back focus. In (lens data), the surface indicates the order of the lens surfaces from the object side, and the interval indicates the interval of the lens surfaces. The surface index is a value with respect to the d-line (λ = 587.6 nm) . Further, a radius of curvature of 0.0000 indicates a plane, and Bf indicates a back focus.
[0042] [0042]
Here, “mm” is generally used as a unit of the focal length f, the radius of curvature, the interval, and other lengths listed in all the following specification values. However, the optical system is not limited to this because an equivalent optical performance can be obtained even when proportionally enlarged or proportionally reduced. Here, “mm” is generally used as a unit of the focal length f, the radius of curvature, the interval, and other lengths listed in all the following specification values. However, the optical system is not limited to this because an equivalent optical performance can be obtained even when proportionally enlarged or proportionally reduced.
In the following specification values of all the examples, the same symbols as those in the present example are used. In the following specification values ​​of all the examples, the same symbols as those in the present example are used.
[0043] [0043]
[Table 1] [Table 1]
(Aspheric coefficient) (Aspheric coefficient)
The sixth lens surface, the sixteenth lens surface, and the twenty-fifth lens surface are aspheric surfaces, and the respective aspheric coefficients are shown below. The sixth lens surface, the sixteenth lens surface, and the twenty-fifth lens surface are aspheric surfaces, and the respective aspheric coefficients are shown below.
(Variable interval data) (Variable interval data)
The variable interval when the lens position state changes is shown below. The variable interval when the lens position state changes is shown below.
(Shift amount of shift lens group) The shift amount δb of the second auxiliary lens group necessary for shifting the image by an amount corresponding to a half angle of view of 0.3 degrees is shown below. (Shift amount of shift lens group) The shift amount δb of the second auxiliary lens group necessary for shifting the image by an amount corresponding to a half angle of view of 0.3 degrees is shown below.
[0044] [0044]
FIGS. 3A, 3B, and 3C are respectively the wide-angle end state (f = 28.80) and the intermediate focal length state (f = 100.00) of the zoom lens according to Example 1 of the present invention. FIG. 6A is a diagram of various aberrations when focusing on infinity in the telephoto end state (f = 291.00). FIGS. 3A, 3B, and 3C are respectively the wide-angle end state (f = 28.80) and the intermediate focal length state (f = 100.00) of the zoom lens according to Example 1 of the present invention. FIG. 6A is a diagram of various aberrations when focusing on infinity in the telephoto end state (f = 291.00).
FIGS. 4A, 4B, and 4C are respectively the wide-angle end state (f = 28.80) and the intermediate focal length state (f = 100.00) of the zoom lens according to Example 1 of the present invention. FIG. 10 is a coma aberration diagram when the second auxiliary lens unit is shifted by the amount shown in Table 1 when focusing on infinity in the telephoto end state (f = 291.00). FIGS. 4A, 4B, and 4C are respectively the wide-angle end state (f = 28.80) and the intermediate focal length state (f = 100.00) of the zoom lens according to Example 1 of the present invention. FIG. 10 is a coma aberration diagram when the second auxiliary lens unit is influenced by the amount shown in Table 1 when focusing on infinity in the telephoto end state (f = 291.00).
[0045] [0045]
3 and 4 are aberration diagrams showing the aberration of the d-line (λ = 587.6 nm). 3 and 4 are aberration diagrams showing the aberration of the d-line (λ = 587.6 nm).
3A, 3B, and 3C, FNO represents an F number, ω represents a half angle of view, and Y represents an image height. In the spherical aberration diagram, the F-number value corresponding to the maximum aperture is shown, and in the astigmatism diagram and the distortion diagram, the maximum image height is shown. In the coma aberration diagram, the values of the half angle of view and the image heights of 0, 10.8, 15.12, 18.34, and 21.6 are shown. Furthermore, in the spherical aberration diagrams, the solid line indicates spherical aberration, and the dotted line indicates sine condition. In the astigmatism diagram, the solid line indicates the sagittal image plane, and the broken line indicates the meridional image plane. 3A, 3B, and 3C, FNO represents an F number, ω represents a half angle of view, and Y represents an image height. In the spherical aberration diagram, the F-number value corresponding to the maximum aperture is shown, and in the Astigmatism diagram and the distortion diagram, the maximum image height is shown. In the coma aberration diagram, the values ​​of the half angle of view and the image heights of 0, 10.8, 15.12, 18.34, and 21.6 are shown. Further, in the Spherical aberration diagrams, the solid line indicates spherical aberration, and the dotted line indicates sine condition. In the astigmatism diagram, the solid line indicates the sagittal image plane, and the broken line indicates the meridional image plane.
4A, 4B, and 4C, ω represents a half angle of view, and Y represents an image height. FIG. 4 shows values of image height Y = −15.0, 0.0, +15.0. 4A, 4B, and 4C, ω represents a half angle of view, and Y represents an image height. FIG. 4 shows values ​​of image height Y = -15.0, 0.0, +15.0.
In addition, in the various aberration diagrams of each example described below, the same reference numerals as those in this example are used. In addition, in the various aberration diagrams of each example described below, the same reference numerals as those in this example are used.
[0046] [0046]
3A, 3B, and 3C, it can be seen that the zoom lens according to the present embodiment corrects various aberrations well and has excellent imaging performance. 3A, 3B, and 3C, it can be seen that the zoom lens according to the present embodiment corrects various aberrations well and has excellent imaging performance.
4A, 4B, and 4C, it can be seen that the zoom lens according to the present example corrects various aberrations during image shift. 4A, 4B, and 4C, it can be seen that the zoom lens according to the present example corrects various aberrations during image shift.
[0047] [0047]
(Second embodiment) (Second embodiment)
FIG. 5 is a diagram showing a lens configuration of a zoom lens according to Example 2 of the present invention. FIG. 5 is a diagram showing a lens configuration of a zoom lens according to Example 2 of the present invention.
In the zoom lens according to the present embodiment, the first lens group G1 includes, in order from the object side, a cemented lens L11 of a meniscus negative lens having a convex surface facing the object side and a positive lens having a convex surface facing the object side, And a meniscus-shaped positive lens L12 having a convex surface on the side. In the zoom lens according to the present embodiment, the first lens group G1 includes, in order from the object side, a cemented lens L11 of a meniscus negative lens having a convex surface facing the object side and a positive lens having a convex surface facing the object side, And a meniscus-shaped positive lens L12 having a convex surface on the side.
The second lens group G2, in order from the object side, includes a negative lens L21 having a concave surface directed toward the image side, a negative lens L22 having a concave surface directed toward the object side, a positive lens L23 having a convex surface directed toward the object side, and an object side And a negative lens L24 having a concave surface on the surface. The second lens group G2, in order from the object side, includes a negative lens L21 having a concave surface directed toward the image side, a negative lens L22 having a concave surface directed toward the object side, a positive lens L23 having a convex surface directed toward the object side, and an object side And a negative lens L24 having a concave surface on the surface.
The third lens group G3 includes, in order from the object side, a cemented positive lens L31 including a biconvex lens and a negative lens having a concave surface facing the object side, a positive lens L32 having a convex surface facing the object side, and a biconvex positive lens. It is composed of a cemented positive lens L33 with a negative lens having a concave surface facing the object side, and a cemented negative lens L34 with a biconcave negative lens and a positive lens having a convex surface facing the image side. The third lens group G3 includes, in order from the object side, a cemented positive lens L31 including a biconvex lens and a negative lens having a concave surface facing the object side, a positive lens L32 having a convex surface facing the object side, and a biconvex positive lens. It is composed of a cemented positive lens L33 with a negative lens having a concave surface facing the object side, and a cemented negative lens L34 with a biconcave negative lens and a positive lens having a convex surface facing the image side ..
The fourth lens group G4 includes, in order from the object side, a positive lens L41 having a convex surface directed toward the image side, and a cemented lens L42 including a biconvex positive lens and a negative lens having a concave surface directed toward the object side. Yes. The fourth lens group G4 includes, in order from the object side, a positive lens L41 having a convex surface directed toward the image side, and a cemented lens L42 including a biconvex positive lens and a negative lens having a concave surface directed toward the object side. Yes.
[0048] [0048]
In the zoom lens according to the present embodiment, the aperture stop S is disposed in the third lens group G3, and moves together with the third lens group G3 when the lens position state changes. In the zoom lens according to the present embodiment, the aperture stop S is disposed in the third lens group G3, and moves together with the third lens group G3 when the lens position state changes.
Further, the negative lens L21 in the second lens group G2 includes an aspheric thin plastic resin layer on the object side lens surface. Further, the negative lens L21 in the second lens group G2 includes an aspheric thin plastic resin layer on the object side lens surface.
In the zoom lens according to the present embodiment, the cemented positive lens L31 and the positive lens L32 in the third lens group G3 are the first auxiliary lens group, the cemented positive lens L33 is the second auxiliary lens group, and the cemented negative lens L34 is the first lens. Each of the three auxiliary lens groups functions as a group. In the zoom lens according to the present embodiment, the cemented positive lens L31 and the positive lens L32 in the third lens group G3 are the first auxiliary lens group, the cemented positive lens L33 is the second auxiliary lens group, and the cemented negative lens L34 is the first lens. Each of the three auxiliary lens groups functions as a group.
Table 2 below provides values of specifications of the zoom lens according to the second example of the present invention. Table 2 below provides values ​​of specifications of the zoom lens according to the second example of the present invention.
[0049] [0049]
[Table 2] [Table 2]
(Aspheric coefficient) (Aspheric coefficient)
The sixth lens surface, the eighteenth lens surface, and the twenty-eighth lens surface are aspheric surfaces, and the respective aspheric coefficients are shown below. The sixth lens surface, the eighteenth lens surface, and the twenty-eighth lens surface are aspheric surfaces, and the respective aspheric coefficients are shown below.
(Variable interval data) (Variable interval data)
The variable interval when the lens position state changes is shown below. The variable interval when the lens position state changes is shown below.
(Shift amount of shift lens group) (Shift amount of shift lens group)
The shift amount δb of the second auxiliary lens group necessary for shifting the image by an amount corresponding to a half angle of view of 0.3 degrees is shown below. The shift amount δb of the second auxiliary lens group necessary for shifting the image by an amount corresponding to a half angle of view of 0.3 degrees is shown below.
[0050] [0050]
FIGS. 6A, 6B, and 6C are respectively the wide-angle end state (f = 28.80) and the intermediate focal length state (f = 100.00) of the zoom lens according to Example 2 of the present invention. FIG. 6A is a diagram showing various aberrations when focusing on infinity in the telephoto end state (f = 290.99). FIGS. 6A, 6B, and 6C are respectively the wide-angle end state (f = 28.80) and the intermediate focal length state (f = 100.00) of the zoom lens according to Example 2 of the present invention. FIG. 6A is a diagram showing various aberrations when focusing on infinity in the telephoto end state (f = 290.99).
FIGS. 7A, 7B, and 7C are respectively the wide-angle end state (f = 28.80) and the intermediate focal length state (f = 100.00) of the zoom lens according to Example 2 of the present invention. FIG. 10 is a coma aberration diagram when the second auxiliary lens unit is shifted by the amount shown in Table 2 above when focusing on infinity in the telephoto end state (f = 290.99). FIGS. 7A, 7B, and 7C are respectively the wide-angle end state (f = 28.80) and the intermediate focal length state (f = 100.00) of the zoom lens according to Example 2 of the present invention. FIG. 10 is a coma aberration diagram when the second auxiliary lens unit is influenced by the amount shown in Table 2 above when focusing on infinity in the telephoto end state (f = 290.99).
[0051] [0051]
6A, 6B, and 6C that the zoom lens according to the present example corrects various aberrations favorably and has excellent imaging performance. 6A, 6B, and 6C that the zoom lens according to the present example corrects various aberrations favorably and has excellent imaging performance.
7A, 7B, and 7C, it can be seen that the zoom lens according to the present example corrects various aberrations during image shift. 7A, 7B, and 7C, it can be seen that the zoom lens according to the present example corrects various aberrations during image shift.
[0052] [0052]
(Third embodiment) (Third embodiment)
FIG. 8 is a diagram showing a lens configuration of a zoom lens according to Example 3 of the present invention. FIG. 8 is a diagram showing a lens configuration of a zoom lens according to Example 3 of the present invention.
In the zoom lens according to the present embodiment, the first lens group G1 includes, in order from the object side, a cemented lens L11 of a meniscus negative lens having a convex surface facing the object side and a positive lens having a convex surface facing the object side, And a meniscus-shaped positive lens L12 having a convex surface on the side. In the zoom lens according to the present embodiment, the first lens group G1 includes, in order from the object side, a cemented lens L11 of a meniscus negative lens having a convex surface facing the object side and a positive lens having a convex surface facing the object side, And a meniscus-shaped positive lens L12 having a convex surface on the side.
The second lens group G2, in order from the object side, includes a negative lens L21 having a concave surface directed toward the image side, a negative lens L22 having a concave surface directed toward the object side, a positive lens L23 having a convex surface directed toward the object side, and an object side And a negative lens L24 having a concave surface on the surface. The second lens group G2, in order from the object side, includes a negative lens L21 having a concave surface directed toward the image side, a negative lens L22 having a concave surface directed toward the object side, a positive lens L23 having a convex surface directed toward the object side, and an object side And a negative lens L24 having a concave surface on the surface.
The third lens group G3 includes, in order from the object side, a cemented positive lens L31 including a biconvex positive lens and a negative lens having a concave surface facing the object side, a positive lens L32 having a convex surface facing the object side, and a biconvex lens. A cemented positive lens L33 composed of a positive lens having a shape and a negative lens having a concave surface facing the object side; and a cemented negative lens L34 composed of a biconcave negative lens and a positive meniscus lens having a convex surface facing the object side. Yes. The third lens group G3 includes, in order from the object side, a cemented positive lens L31 including a biconvex positive lens and a negative lens having a concave surface facing the object side, a positive lens L32 having a convex surface facing the object side, and a biconvex lens. A cemented positive lens L33 composed of a positive lens having a shape and a negative lens having a concave surface facing the object side; and a cemented negative lens L34 composed of a biconcave negative lens and a positive meniscus lens having a convex surface facing the object side. Yes.
The fourth lens group G4 includes, in order from the object side, a positive lens L41 having a convex surface directed toward the image side, and a cemented lens L42 including a biconvex positive lens and a negative lens having a concave surface directed toward the object side. Yes. The fourth lens group G4 includes, in order from the object side, a positive lens L41 having a convex surface directed toward the image side, and a cemented lens L42 including a biconvex positive lens and a negative lens having a concave surface directed toward the object side. Yes.
[0053] [0053]
In the zoom lens according to the present embodiment, the aperture stop S is disposed in the third lens group G3, and moves together with the third lens group G3 when the lens position state changes. In the zoom lens according to the present embodiment, the aperture stop S is disposed in the third lens group G3, and moves together with the third lens group G3 when the lens position state changes.
Further, the negative lens L21 in the second lens group G2 includes an aspheric thin plastic resin layer on the object side lens surface. Further, the negative lens L21 in the second lens group G2 includes an aspheric thin plastic resin layer on the object side lens surface.
In the zoom lens according to the present embodiment, the cemented positive lens L31 and the positive lens L32 in the third lens group G3 are the first auxiliary lens group, the cemented positive lens L33 is the second auxiliary lens group, and the cemented negative lens L34 is. This is a configuration that functions as a third auxiliary lens group. In the zoom lens according to the present embodiment, the cemented positive lens L31 and the positive lens L32 in the third lens group G3 are the first auxiliary lens group, the cemented positive lens L33 is the second auxiliary lens group, and the cemented negative lens L34 is. This is a configuration that functions as a third auxiliary lens group.
Table 3 below lists values of specifications of the zoom lens according to the third example of the present invention. Table 3 below lists values ​​of specifications of the zoom lens according to the third example of the present invention.
[0054] [0054]
(Table 3) (Table 3)
(Overall specifications) (Overall specifications)
Wide-angle end state Intermediate focal length state Telephoto end state f 28.80 to 100.00 to 291.01 Wide-angle end state Intermediate focal length state Telephoto end state f 28.80 to 100.00 to 291.01
FNO 3.70 to 5.32 to 5.90 FNO 3.70 to 5.32 to 5.90
2ω 76.77 〜 23.72 〜 8.27 ° 2ω 76.77 ~ 23.72 ~ 8.27 °
(Lens data) (Lens data)
Surface Curvature radius Interval Refractive index Abbe number Surface Curvature radius Interval Refractive index Abbe number
1 92.4229 1.900 1.84666 23.78 1 92.4229 1.900 1.84666 23.78
2 66.7560 7.750 1.49700 81.61 2 66.7560 7.750 1.49700 81.61
3 -846.2717 0.100 1.0 3 -846.2717 0.100 1.0
4 63.6267 4.950 1.49700 81.61 4 63.6267 4.950 1.49700 81.61
5 165.9874 (D5) 1.0 5 165.9874 (D5) 1.0
6 128.4411 0.200 1.51742 52.42 6 128.4411 0.200 1.51742 52.42
7 101.5414 1.150 1.72916 54.66 7 101.5414 1.150 1.72916 54.66
8 17.1504 6.250 1.0 8 17.1504 6.250 1.0
9 -46.5218 1.000 1.75500 52.32 9 -46.5218 1.000 1.75500 52.32
10 66.4470 0.100 1.0 10 66.4470 0.100 1.0
11 33.9329 4.200 1.84666 23.78 11 33.9329 4.200 1.84666 23.78
12 -53.7522 1.800 1.0 12 -53.7522 1.800 1.0
13 -26.2934 0.900 1.83481 42.72 13 -26.2934 0.900 1.83481 42.72
14 -885.5810 (D14) 1.0 14 -885.5810 (D14) 1.0
15 0.0000 2.200 1.0 (Aperture stop) 15 0.0000 2.200 1.0 (Aperture stop)
16 23.3505 7.000 1.58913 61.18 16 23.3505 7.000 1.58913 61.18
17 -25.1524 0.800 1.80400 46.58 17 -25.1524 0.800 1.80400 46.58
18 -280.9645 0.100 1.0 18 -280.9645 0.100 1.0
19 37.9321 3.200 1.51633 64.14 19 37.9321 3.200 1.51633 64.14
20 -414.9721 4.050 1.0 20 -414.9721 4.050 1.0
21 34.8328 3.850 1.75500 52.32 21 34.8328 3.850 1.75500 52.32
22 -60.1069 0.800 1.84666 23.78 22 -60.1069 0.800 1.84666 23.78
23 -456.9696 3.100 1.0 23 -456.9696 3.100 1.0
24 -21.2766 0.800 1.83400 37.17 24-21.2766 0.800 1.83400 37.17
25 32.5985 2.650 1.48749 70.24 25 32.5985 2.650 1.48749 70.24
26 863.3676 (D26) 1.0 26 863.3676 (D26) 1.0
27 145.6193 3.600 1.51633 64.14 27 145.6193 3.600 1.51633 64.14
28 -30.7860 0.100 1.0 28 -30.7860 0.100 1.0
29 629.7219 7.700 1.66680 33.04 29 629.7219 7.700 1.66680 33.04
30 -13.2652 0.900 1.83481 42.72 30 -13.2652 0.900 1.83481 42.72
31 -80.0893 (Bf) 1.0 31 -80.0893 (Bf) 1.0
(Aspheric coefficient) (Aspheric coefficient)
The sixth lens surface, the sixteenth lens surface, and the twenty-eighth lens surface are aspheric surfaces, and the respective aspheric coefficients are shown below. The sixth lens surface, the sixteenth lens surface, and the twenty-eighth lens surface are aspheric surfaces, and the respective aspheric coefficients are shown below.
[Sixth page] [Sixth page]
κ = -4.2585 C 4 = + 4.4810 × 10 - 6 C 6 = + 1.2417 × 10 - 8 κ = -4.2585 C 4 = + 4.4810 x 10 --6 C 6 = + 1.2417 x 10 --8
C 8 = -1.0672 × 10 - 10 C 10 = + 3.1231 × 10 - 13 C 8 = -1.0672 x 10 --10 C 10 = + 3.1231 x 10 --13
[16th page] [16th page]
κ = 1.0000 C 4 = -3.9585 × 10 - 6 C 6 = + 4.2904 × 10 - 9 κ = 1.0000 C 4 = -3.9585 × 10 ―― 6 C 6 = + 4.2904 × 10 ―― 9
C 8 = -8.0515 × 10 - 12 C 10 = + 4.2777 × 10 - 14 C 8 = -8.0515 × 10 ―― 12 C 10 = + 4.2777 × 10 ―― 14
[Section 28] [Section 28]
κ = 1.0000 C 4 = + 1.0383 × 10 - 5 C 6 = -1.4668 × 10 - 8 κ = 1.0000 C 4 = + 1.0383 × 10 ―― 5 C 6 = -1.4668 × 10 ―― 8
C 8 = + 1.2224 × 10 - 10 C 10 = -1.4347 × 10 - 12 C 8 = + 1.2224 x 10 --10 C 10 = -1.4347 x 10 --12
(Variable interval data) (Variable interval data)
The variable interval when the lens position state changes is shown below. The variable interval when the lens position state changes is shown below.
Wide-angle end state Intermediate focal length state Telephoto end state f 28.8001 100.0017 291.0077 Wide-angle end state Intermediate focal length state Telephoto end state f 28.8001 100.0017 291.0077
D7 1.5358 36.1674 61.1207 D7 1.5358 36.1674 61.1207
D16 27.1675 12.0649 0.8000 D16 27.1675 12.0649 0.8000
D23 6.3826 2.6488 2.0000 D23 6.3826 2.6488 2.0000
BF 39.5003 75.7001 90.8947 BF 39.5003 75.7001 90.8947
(Shift amount of shift lens group) (Shift amount of shift lens group)
The shift amount δb of the second auxiliary lens group necessary for shifting the image by an amount corresponding to a half angle of view of 0.3 degrees is shown below. The shift amount δb of the second auxiliary lens group necessary for shifting the image by an amount corresponding to a half angle of view of 0.3 degrees is shown below.
Wide-angle end state Intermediate focal length state Telephoto end state f 28.8001 100.0017 291.0077 Wide-angle end state Intermediate focal length state Telephoto end state f 28.8001 100.0017 291.0077
δb 0.1123 0.2444 0.6095 δb 0.1123 0.2444 0.6095
(Values for conditional expressions) (Values ​​for conditional expressions)
fA = 224.755 fA = 224.755
fa = 30.182 fa = 30.182
fc = -19.750 fc = -19.750
f3 = 35.153 f3 = 35.153
(1) Ds / fw = 0.602 (1) Ds / fw = 0.602
(2) ft / fA = 1.295 (2) ft / fA = 1.295
(3) fa / ft = 0.104 (3) fa / ft = 0.104
(4) (na / ra) / (nb / rb) = -0.080 (4) (na / ra) / (nb / rb) = -0.080
(5) | fc | /f3=0.562 (5) | fc | / f3 = 0.562
(6) | rc | /f3=0.605 (6) | rc | /f3=0.605
[0055] [0055]
FIGS. 9A, 9B, and 9C are respectively a wide-angle end state (f = 28.80) and an intermediate focal length state (f = 100.00) of the zoom lens according to the third example of the present invention. FIG. 6A shows various aberrations when focusing on infinity in the telephoto end state (f = 291.00). FIGS. 9A, 9B, and 9C are respectively a wide-angle end state (f = 28.80) and an intermediate focal length state (f = 100.00) of the zoom lens according to the third example of the present invention. FIG. 6A shows various aberrations when focusing on infinity in the telephoto end state (f = 291.00).
FIGS. 10A, 10B, and 10C are respectively the wide-angle end state (f = 28.80) and the intermediate focal length state (f = 100.00) of the zoom lens according to Example 3 of the present invention. The coma aberration diagram when the second auxiliary lens unit is shifted by the amount shown in Table 3 at the time of focusing on infinity in the telephoto end state (f = 291.00) is shown. FIGS. 10A, 10B, and 10C are respectively the wide-angle end state (f = 28.80) and the intermediate focal length state (f = 100.00) of the zoom lens according to Example 3 of the present invention. The coma aberration diagram when the second auxiliary lens unit is intermediate by the amount shown in Table 3 at the time of focusing on infinity in the telephoto end state (f = 291.00) is shown.
[0056] [0056]
9A, 9B, and 9C show that the zoom lens according to the present embodiment corrects various aberrations well and has excellent imaging performance. 9A, 9B, and 9C show that the zoom lens according to the present embodiment corrects various aberrations well and has excellent imaging performance.
10 (a), (b), and (c), it can be seen that the zoom lens according to the present embodiment corrects various aberrations during image shift. 10 (a), (b), and (c), it can be seen that the zoom lens according to the present embodiment corrects various aberrations during image shift.
[0057] [0057]
【The invention's effect】 [The invention's effect]
According to the present invention, the total lens length in the wide-angle end state is relatively short, and there is little change in the total lens length when the lens position changes from the wide-angle end state to the telephoto end state. A zoom lens having a high zoom ratio that can move an image by moving in a direction substantially perpendicular to the optical axis can be provided. According to the present invention, the total lens length in the wide-angle end state is relatively short, and there is little change in the total lens length when the lens position changes from the wide-angle end state to the telephoto end state. zoom lens having a high zoom ratio that can move an image by moving in a direction substantially perpendicular to the optical axis can be provided.
[Brief description of the drawings] [Brief description of the drawings]
FIG. 1 is a diagram showing refractive power distribution of a variable focal length lens system (zoom lens) according to each embodiment of the present invention. FIG. 1 is a diagram showing optical power distribution of a variable focal length lens system (zoom lens) according to each embodiment of the present invention.
FIG. 2 is a diagram illustrating a lens configuration of a zoom lens according to a first example of the present invention. FIG. 2 is a diagram illustrating a lens configuration of a zoom lens according to a first example of the present invention.
FIGS. 3A, 3B, and 3C are a wide-angle end state (f = 28.80) and an intermediate focal length state (f = 100.n) of the zoom lens according to Example 1 of the present invention, respectively. 00) and various aberration diagrams at the time of focusing on infinity in the telephoto end state (f = 291.00). FIGS. 3A, 3B, and 3C are a wide-angle end state (f = 28.80) and an intermediate focal length state (f = 100.n) of the zoom lens according to Example 1 of the present invention, respectively. 00) and various aberration diagrams at the time of focusing on infinity in the telephoto end state (f = 291.00).
FIGS. 4A, 4B, and 4C are a wide-angle end state (f = 28.80) and an intermediate focal length state (f = 100.f) of the zoom lens according to Example 1 of the present invention, respectively. 00) is a coma aberration diagram when the second auxiliary lens unit is shifted at the time of focusing on infinity in the telephoto end state (f = 291.00). FIGS. 4A, 4B, and 4C are a wide-angle end state (f = 28.80) and an intermediate focal length state (f = 100.f) of the zoom lens according to Example 1 of the present invention, respectively. 00) is a coma aberration diagram when the second auxiliary lens unit is aberrationd at the time of focusing on infinity in the telephoto end state (f = 291.00).
FIG. 5 is a diagram showing a lens configuration of a zoom lens according to a second example of the present invention. FIG. 5 is a diagram showing a lens configuration of a zoom lens according to a second example of the present invention.
FIGS. 6A, 6B, and 6C are a wide-angle end state (f = 28.80) and an intermediate focal length state (f = 100.f) of a zoom lens according to Example 2 of the present invention, respectively. 00) and various aberrations at the time of focusing on infinity in the telephoto end state (f = 290.99). FIGS. 6A, 6B, and 6C are a wide-angle end state (f = 28.80) and an intermediate focal length state (f = 100.f) of a zoom lens according to Example 2 of the present invention, respectively. 00) and various aberrations at the time of focusing on infinity in the telephoto end state (f = 290.99).
FIGS. 7A, 7B, and 7C are a wide-angle end state (f = 28.80) and an intermediate focal length state (f = 100.f) of a zoom lens according to Example 2 of the present invention, respectively. 00) is a coma aberration diagram when the second auxiliary lens unit is shifted at the time of focusing on infinity in the telephoto end state (f = 290.99). FIGS. 7A, 7B, and 7C are a wide-angle end state (f = 28.80) and an intermediate focal length state (f = 100.f) of a zoom lens according to Example 2 of the present invention, respectively. 00) is a coma aberration diagram when the second auxiliary lens unit is aberrationd at the time of focusing on infinity in the telephoto end state (f = 290.99).
FIG. 8 is a diagram illustrating a lens configuration of a zoom lens according to a third example of the present invention. FIG. 8 is a diagram illustrating a lens configuration of a zoom lens according to a third example of the present invention.
FIGS. 9A, 9B and 9C are a wide angle end state (f = 28.80) and an intermediate focal length state (f = 100. 00) and various aberration diagrams at the time of focusing on infinity in the telephoto end state (f = 291.00). FIGS. 9A, 9B and 9C are a wide angle end state (f = 28.80) and an intermediate focal length state (f = 100. 00) and various aberration diagrams at the time of focusing on infinity in the telephoto end state (f = 291.00).
FIGS. 10A, 10B, and 10C are respectively a wide angle end state (f = 28.80) and an intermediate focal length state (f = 100.f) of a zoom lens according to Example 3 of the present invention. 00) is a coma aberration diagram when the second auxiliary lens unit is shifted at the time of focusing on infinity in the telephoto end state (f = 291.00). FIGS. 10A, 10B, and 10C are respectively a wide angle end state (f = 28.80) and an intermediate focal length state (f = 100.f) of a zoom lens according to Example 3 of the present invention. 00) is a coma aberration diagram when the second auxiliary lens unit is aberrationd at the time of focusing on infinity in the telephoto end state (f = 291.00).
[Explanation of symbols] [Explanation of symbols]
G1: First lens group G2: Second lens group G3: Third lens group G4: Fourth lens group S: Aperture stop I: Image plane G1: First lens group G2: Second lens group G3: Third lens group G4: Fourth lens group S: Aperture stop I: Image plane

Claims (8)

  1. 物体側より順に、正の屈折力を有する第1レンズ群と、負の屈折力を有する第2レンズ群と、正の屈折力を有する第3レンズ群と、正の屈折力を有する第4レンズ群とからなり
    前記第3レンズ群内部又は前記第3レンズ群近傍に、前記第3レンズ群と共に光軸に沿って移動する開口絞りが配置されており、
    広角端状態から望遠端状態への変倍の際に、前記第1レンズ群と前記第2レンズ群との間隔が増大し、前記第2レンズ群と前記第3レンズ群との間隔が減少し、前記第3レンズ群と前記第4レンズ群との間隔が減少するように、少なくとも前記第1レンズ群及び前記第4レンズ群が物体側へ移動し、
    前記第3レンズ群は、第1補助レンズ群と、第2補助レンズ群と、第3補助レンズ群とからなり、前記第2補助レンズ群は前記第1補助レンズ群の像側に空気間隔を隔てて配置されており、前記第3補助レンズ群は前記第2補助レンズ群の像側に空気間隔を隔てて配置されており、 The third lens group includes a first auxiliary lens group, a second auxiliary lens group, and a third auxiliary lens group, the second auxiliary lens group air space on an image side of the first auxiliary lens group The third auxiliary lens group is arranged at a distance, and the third auxiliary lens group is arranged at an air interval on the image side of the second auxiliary lens group.
    前記第2補助レンズ群を前記光軸に対して略垂直な方向へ移動させることによって、像を移動させることが可能であり By moving to a direction substantially perpendicular to the optical axis of the second auxiliary lens group, it is possible to move the image,
    以下の条件式を満足することを特徴とするズームレンズ。 A zoom lens characterized by satisfying the following conditional expression.
    0.05<Ds/fw<0.7 0.05 <Ds / fw <0.7
    0.1<ft/fA<1.5 0.1 <ft / fA <1.5
    但し、 However,
    Ds:前記開口絞りから、前記第2補助レンズ群のレンズ面のうちの前記開口絞りに最も近いレンズ面までの光軸に沿った距離, Ds: The distance along the optical axis from the aperture diaphragm to the lens surface of the lens surface of the second auxiliary lens group closest to the aperture diaphragm.
    fw:広角端状態における前記ズームレンズ全体の焦点距離, fw: Focal length of the entire zoom lens in the wide-angle end state,
    fA:望遠端状態における前記第2補助レンズ群よりも物体側に位置する全てのレンズによる焦点距離, fA: Focal length of all lenses located closer to the object than the second auxiliary lens group in the telephoto end state,
    ft:望遠端状態における前記ズームレンズ全体の焦点距離. ft: Focal length of the entire zoom lens in the telephoto end state. In order from the object side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, and a fourth lens having a positive refractive power It consists of a group, In order from the object side, a first lens group having a positive optical power, a second lens group having a negative optical power, a third lens group having a positive optical power, and a fourth lens having a positive optical power It consists of a group,
    An aperture stop that moves along the optical axis together with the third lens group is disposed in the third lens group or in the vicinity of the third lens group, An aperture stop that moves along the optical axis together with the third lens group is disposed in the third lens group or in the vicinity of the third lens group,
    During zooming from the wide-angle end state to the telephoto end state , the distance between the first lens group and the second lens group increases, and the distance between the second lens group and the third lens group decreases. , At least the first lens group and the fourth lens group move toward the object side so that the distance between the third lens group and the fourth lens group is reduced, During zooming from the wide-angle end state to the telephoto end state , the distance between the first lens group and the second lens group increases, and the distance between the second lens group and the third lens group decreases., At least the first lens group and the fourth lens group move toward the object side so that the distance between the third lens group and the fourth lens group is reduced,
    The third lens group includes a first auxiliary lens group, a second auxiliary lens group, and a third auxiliary lens group, the second auxiliary lens group air space on an image side of the first auxiliary lens group The third auxiliary lens group is arranged with an air gap on the image side of the second auxiliary lens group, The third lens group includes a first auxiliary lens group, a second auxiliary lens group, and a third auxiliary lens group, the second auxiliary lens group air space on an image side of the first auxiliary lens group The third auxiliary lens group is arranged with an air gap on the image side of the second auxiliary lens group,
    By moving to a direction substantially perpendicular to the optical axis of the second auxiliary lens group, it is possible to move the image, By moving to a direction substantially perpendicular to the optical axis of the second auxiliary lens group, it is possible to move the image,
    A zoom lens satisfying the following conditional expression: A zoom lens satisfying the following conditional expression:
    0.05 <Ds / fw <0.7 0.05 <Ds / fw <0.7
    0.1 <ft / fA <1.5 0.1 <ft / fA <1.5
    However, However,
    Ds: the distance along the optical axis from the aperture stop to the lens surface closest to the aperture stop among the lens surfaces of the second auxiliary lens group, Ds: the distance along the optical axis from the aperture stop to the lens surface closest to the aperture stop among the lens surfaces of the second auxiliary lens group,
    fw: focal length of the entire zoom lens in the wide-angle end state, fw: focal length of the entire zoom lens in the wide-angle end state,
    fA: the focal length of all the lenses located on the object side of the second auxiliary lens group in the telephoto end state, fA: the focal length of all the lenses located on the object side of the second auxiliary lens group in the telephoto end state,
    ft: focal length of the entire zoom lens in the telephoto end state. ft: focal length of the entire zoom lens in the telephoto end state.
  2. 前記第2補助レンズ群は、1枚の正レンズと1枚の負レンズとを少なくとも有し、正の屈折力を有するとともに、
    以下の条件式を満足することを特徴とする請求項1に記載のズームレンズ。
    −0.6<(na/ra)/(nb/rb)<0
    但し、

    ra:前記第2補助レンズ群中の最も物体側のレンズ面の曲率半径, ra: Radius of curvature of the lens surface on the most object side in the second auxiliary lens group,
    na:前記第2補助レンズ群中の最も物体側のレンズのd線に対する屈折率, na: Refractive index of the lens on the most object side in the second auxiliary lens group with respect to the d line,
    rb:前記第2補助レンズ群中の最も像側のレンズ面の曲率半径, rb: Radius of curvature of the lens surface on the image side of the second auxiliary lens group,
    nb:前記第2補助レンズ群中の最も像側のレンズのd線に対する屈折率. nb: Refractive index of the lens on the image side of the second auxiliary lens group with respect to the d line. The second auxiliary lens group has at least one positive lens and one negative lens, has positive refractive power, The second auxiliary lens group has at least one positive lens and one negative lens, has positive refracting power,
    The zoom lens according to claim 1, wherein the following conditional expression is satisfied. The zoom lens according to claim 1, wherein the following conditional expression is satisfied.
    −0.6 <(na / ra) / (nb / rb) <0 −0.6 <(na / ra) / (nb / rb) <0
    However, However,
    ra: radius of curvature of the lens surface closest to the object side in the second auxiliary lens group, ra: radius of curvature of the lens surface closest to the object side in the second auxiliary lens group,
    na: refractive index with respect to d-line of the most object side lens in the second auxiliary lens group, na: refractive index with respect to d-line of the most object side lens in the second auxiliary lens group,
    rb: radius of curvature of the lens surface closest to the image side in the second auxiliary lens group, rb: radius of curvature of the lens surface closest to the image side in the second auxiliary lens group,
    nb: Refractive index with respect to d-line of the most image side lens in the second auxiliary lens group. nb: Refractive index with respect to d-line of the most image side lens in the second auxiliary lens group.
  3. 前記第3補助レンズ群は、負の屈折力を有するとともに、
    以下の条件式を満足することを特徴とする請求項1又は請求項2に記載のズームレンズ。
    0.5<|fc|/f3<0.9
    但し、
    fc:前記第3補助レンズ群の焦点距離,
    f3:前記第3レンズ群の焦点距離.
    The third auxiliary lens group has negative refractive power,
    The zoom lens according to claim 1, wherein the following conditional expression is satisfied.
    0.5 <| fc | / f3 <0.9
    However,
    fc: focal length of the third auxiliary lens group,

    f3: Focal length of the third lens group. f3: Focal length of the third lens group.
  4. 前記第3補助レンズ群は、物体側に凹面を向けた負レンズを最も物体側に有し、
    以下の条件式を満足することを特徴とする請求項3に記載のズームレンズ。
    0.5<|rc|/f3<0.75
    但し、
    rc:前記第3補助レンズ群中の最も物体側に配置された前記負レンズの物体側のレンズ面の曲率半径.
    The third auxiliary lens group has a negative lens closest to the object side with a concave surface facing the object side,
    The zoom lens according to claim 3, wherein the following conditional expression is satisfied.
    0.5 <| rc | / f3 <0.75
    However,
    rc: radius of curvature of the object-side lens surface of the negative lens arranged closest to the object side in the third auxiliary lens group.
  5. 前記第3レンズ群の前記第1補助レンズ群は、非球面を有することを特徴とする請求項1から請求項4のいずれか1項に記載のズームレンズ。 The zoom lens according to any one of claims 1 to 4 , wherein the first auxiliary lens group of the third lens group has an aspherical surface.
  6. 前記第2レンズ群と前記第4レンズ群は、非球面を有することを特徴とする請求項1から請求項5のいずれか1項に記載のズームレンズ。 The zoom lens according to any one of claims 1 to 5, wherein the second lens group and the fourth lens group have an aspherical surface.
  7. 前記第1レンズ群は、非球面を有することを特徴とする請求項1から請求項6のいずれか1項に記載のズームレンズ。 The zoom lens according to claim 1 , wherein the first lens group has an aspherical surface.
  8. 近距離合焦時に、前記第2レンズ群を前記光軸方向に移動させることを特徴とする請求項1から請求項7のいずれか1項に記載のズームレンズ。 When short-distance focusing, zoom lens as claimed in any one of claims 7, characterized in that moving the second lens group in the optical axis direction.
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JP4635688B2 (en) * 2005-03-31 2011-02-23 株式会社ニコン Zoom lens with anti-vibration function
JP4817699B2 (en) * 2005-04-01 2011-11-16 キヤノン株式会社 Zoom lens and imaging apparatus having the same
KR100671544B1 (en) 2005-06-10 2007-01-19 삼성전자주식회사 Zoom lens optical system
JP5042643B2 (en) * 2007-01-22 2012-10-03 パナソニック株式会社 Zoom lens system, imaging device and camera
CN102089699B (en) * 2008-07-09 2014-02-05 株式会社尼康 Zoom lens, optical device having same, and zoom lens manufacturing method
JP5201461B2 (en) * 2008-07-09 2013-06-05 株式会社ニコン Zoom lens, optical apparatus having the same, and zooming method
JP5201460B2 (en) * 2008-07-09 2013-06-05 株式会社ニコン Zoom lens, optical apparatus having the same, and zooming method
JP5241377B2 (en) * 2008-08-19 2013-07-17 キヤノン株式会社 Zoom lens and imaging apparatus having the same
JP4905429B2 (en) * 2008-09-25 2012-03-28 株式会社ニコン Zoom lens
JP5678424B2 (en) 2009-11-26 2015-03-04 株式会社ニコン Variable magnification optical system, optical apparatus equipped with the variable magnification optical system, and method of manufacturing the variable magnification optical system

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