JP2021039379A

JP2021039379A - Optical system and imaging apparatus including the same

Info

Publication number: JP2021039379A
Application number: JP2020196094A
Authority: JP
Inventors: 裕一行田; Yuichi Gyoda
Original assignee: Canon Inc
Current assignee: Canon Inc
Priority date: 2020-11-26
Filing date: 2020-11-26
Publication date: 2021-03-11
Anticipated expiration: 2036-06-01
Also published as: JP7059340B2

Abstract

To provide an optical system that is lightweight and has satisfactorily corrected chromatic aberrations and the like.SOLUTION: An optical system is composed of a first lens group B1 having positive refractive power, a second lens group B2 moving during focusing and having positive refractive power, and a third lens group B3 having positive or negative refractive power that are arranged in order from an object side to an image side. A distance between the lens groups adjacent to each other changes during focusing. The optical system appropriately sets: a focal distance f of an entire system; a distance LD on an optical axis from a lens surface closest to the object side of the optical system to an image surface IP; and a distance L on an optical axis from a lens surface closest to the object side of the second lens group B2 during focusing in an infinite distance to the image surface IP.SELECTED DRAWING: Figure 1

Description

本発明は光学系及びそれを有する撮像装置に関し、例えばデジタルスチルカメラ、ビデオカメラ、監視カメラ、放送用カメラ等の撮像素子を用いた撮像装置、或いは銀塩写真フィルムを用いたカメラ等の撮像装置に好適なものである。 The present invention relates to an optical system and an image pickup device having the same, for example, an image pickup device using an image pickup element such as a digital still camera, a video camera, a surveillance camera, a broadcasting camera, or an image pickup device such as a camera using a silver salt photographic film. It is suitable for.

焦点距離の長い撮影光学系として、物体側に正の屈折力の光学系を配置し、像側に負の屈折力の光学系を配置した、いわゆるテレフォトタイプの撮影光学系が知られている。テレフォトタイプの撮影光学系は、例えば単焦点の超望遠レンズに用いられている。 As a photographing optical system having a long focal length, a so-called telephoto type photographing optical system in which a positive refractive power optical system is arranged on the object side and a negative refractive power optical system is arranged on the image side is known. .. The telephoto type photographic optical system is used, for example, in a single focus super-telephoto lens.

特許文献１は、物体側から像側へ順に配置された、正の屈折力の第１レンズ群、負の屈折力の第２レンズ群、正の屈折力の第３レンズ群から構成される撮影光学系を開示している。 Patent Document 1 is composed of 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 arranged in order from the object side to the image side. The optical system is disclosed.

特開２０１５−２１５５６１号公報Japanese Unexamined Patent Publication No. 2015-215561

特許文献１に記載の撮影光学系では、フォーカシングに際して負の屈折力の第２レンズ群を移動させている。ここで、第２レンズ群は比較的第１レンズ群に近い位置に配置されており、フォーカス群の小型化及び軽量化を十分に実現できているとは言えない。 In the photographing optical system described in Patent Document 1, the second lens group having a negative refractive power is moved during focusing. Here, the second lens group is arranged at a position relatively close to the first lens group, and it cannot be said that the focus group can be sufficiently reduced in size and weight.

また、負の屈折力の第２レンズ群をフォーカシングに際して移動させると、第２レンズ群における光線の発散作用により第２レンズ群よりも像側に配置されたレンズの有効径が大きくなりやすい。その結果、撮影光学系の小型化及び軽量化が不十分となるおそれがある。また、軸上光線の高さが比較的高い位置にフォーカス群を配置することで、フォーカシングに際しての色収差の変動が大きくなりやすい。 Further, when the second lens group having a negative refractive power is moved during focusing, the effective diameter of the lens arranged on the image side of the second lens group tends to be larger than that of the second lens group due to the divergence of light rays in the second lens group. As a result, the miniaturization and weight reduction of the photographing optical system may be insufficient. Further, by arranging the focus group at a position where the height of the axial light beam is relatively high, the fluctuation of chromatic aberration during focusing tends to be large.

本発明は、軽量であり、かつ色収差等の収差が良好に補正された光学系及びそれを有する撮像装置を提供することを目的とする。 An object of the present invention is to provide an optical system that is lightweight and has chromatic aberration and other aberrations satisfactorily corrected, and an image pickup apparatus having the same.

本発明の光学系は、物体側より像側へ順に配置された、正の屈折力を有する第１レンズ群、正の屈折力を有する第２レンズ群、正または負の屈折力を有する第３レンズ群から構成され、フォーカシングに際して前記第２レンズ群が移動し、隣り合うレンズ群の間隔が変化する光学系であって、前記光学系の最も物体側のレンズ面から像面までの光軸上の距離をＬＤ、無限遠に合焦しているときにおける前記第２レンズ群の最も物体側のレンズ面から像面までの光軸上の距離をＬ、前記光学系の焦点距離をｆとしたとき、
ＬＤ／ｆ＜１．００
０．１５＜Ｌ／ｆ＜０．４８
なる条件式を満足することを特徴とする。 In the optical system of the present invention, a first lens group having a positive refractive power, a second lens group having a positive refractive power, and a third lens group having a positive or negative refractive power are arranged in order from the object side to the image side. An optical system composed of lens groups, in which the second lens group moves during focusing and the distance between adjacent lens groups changes, and is on the optical axis from the lens surface to the image surface on the most object side of the optical system. The distance of is LD, the distance on the optical axis from the lens surface on the most object side of the second lens group to the image surface when in focus at infinity is L, and the focal distance of the optical system is f. When
LD / f <1.00
0.15 <L / f <0.48
It is characterized in that it satisfies the conditional expression.

本発明によれば、軽量であり、かつ色収差等の収差が良好に補正された光学系を得ることができる。 According to the present invention, it is possible to obtain an optical system that is lightweight and has well corrected aberrations such as chromatic aberration.

実施例１の光学系のレンズ断面図である。It is a lens sectional view of the optical system of Example 1. FIG. （Ａ）、（Ｂ）無限遠に合焦しているとき、最至近距離に合焦しているときにおける実施例１の光学系の収差図である。(A), (B) It is an aberration diagram of the optical system of Example 1 when it is focused at infinity, and when it is focused at the closest distance. 実施例２の光学系のレンズ断面図である。It is a lens sectional view of the optical system of Example 2. FIG. （Ａ）、（Ｂ）無限遠に合焦しているとき、最至近距離に合焦しているときにおける実施例２の光学系の収差図である。(A), (B) It is an aberration diagram of the optical system of Example 2 when it is focused at infinity, and when it is focused at the closest distance. 実施例３の光学系のレンズ断面図である。It is a lens sectional view of the optical system of Example 3. FIG. （Ａ）、（Ｂ）無限遠に合焦しているとき、最至近距離に合焦しているときにおける実施例３の光学系の収差図である。(A), (B) It is an aberration diagram of the optical system of Example 3 when it is focused at infinity, and when it is focused at the closest distance. 実施例４の光学系のレンズ断面図である。It is a lens sectional view of the optical system of Example 4. FIG. （Ａ）、（Ｂ）無限遠に合焦しているとき、最至近距離に合焦しているときにおける実施例４の光学系の収差図である。(A), (B) It is an aberration diagram of the optical system of Example 4 when it is focused at infinity, and when it is focused at the closest distance. 実施例５の光学系のレンズ断面図である。It is a lens sectional view of the optical system of Example 5. （Ａ）、（Ｂ）無限遠に合焦しているとき、最至近距離に合焦しているときにおける実施例５の光学系の収差図である。(A), (B) It is an aberration diagram of the optical system of Example 5 when it is focused at infinity, and when it is focused at the closest distance. 実施例６の光学系のレンズ断面図である。It is a lens sectional view of the optical system of Example 6. （Ａ）、（Ｂ）無限遠に合焦しているとき、最至近距離に合焦しているときにおける実施例６の光学系の収差図である。(A), (B) It is an aberration diagram of the optical system of Example 6 when it is focused at infinity, and when it is focused at the closest distance. 本発明の撮像装置の要部概略図である。It is a schematic diagram of the main part of the image pickup apparatus of this invention.

以下、本発明の光学系及びそれを有する撮像装置について、添付の図面に基づいて詳細に説明する。本発明の光学系は、物体側より像側へ順に配置された、正の屈折力の第１レンズ群、正の屈折力の第２レンズ群、正または負の屈折力の第３レンズ群から構成される。フォーカシングに際して第２レンズ群が移動し、隣り合うレンズ群の間隔が変化する。ここでレンズ群とは、フォーカシングに際して一体的に移動するレンズ要素であって、１枚以上のレンズを有していればよく、複数枚のレンズを有していなくてもよい。 Hereinafter, the optical system of the present invention and an imaging apparatus having the same will be described in detail with reference to the accompanying drawings. The optical system of the present invention is composed of a first lens group having a positive refractive power, a second lens group having a positive refractive power, and a third lens group having a positive or negative refractive power arranged in order from the object side to the image side. It is composed. During focusing, the second lens group moves, and the distance between adjacent lens groups changes. Here, the lens group is a lens element that moves integrally during focusing, and may have one or more lenses, and may not have a plurality of lenses.

図１、３、５、７、９、１１は、それぞれ実施例１乃至６の光学系のレンズ断面図である。図２、４、６、８、１０、１２は、それぞれ無限遠に合焦しているとき、最至近距離に合焦しているときにおける実施例１乃至６の光学系の収差図である。 1, 3, 5, 7, 9 and 11 are lens cross-sectional views of the optical systems of Examples 1 to 6, respectively. FIGS. 2, 4, 6, 8, 10 and 12 are aberration diagrams of the optical systems of Examples 1 to 6 when they are in focus at infinity and when they are in focus at the closest distance, respectively.

図１３は、本発明の光学系を備える撮像装置の要部概略図である。各実施例の光学系はビデオカメラやデジタルカメラ、銀塩フィルムカメラ、テレビカメラ等の撮像装置に用いられる撮影レンズ系である。レンズ断面図において左方が物体側（前方）で、右方が像側（後方）である。またレンズ断面図において、ｉを物体側から像側へのレンズ群の順番とするとＢｉは第ｉレンズ群を示す。 FIG. 13 is a schematic view of a main part of an image pickup apparatus including the optical system of the present invention. The optical system of each embodiment is a photographing lens system used in an imaging device such as a video camera, a digital camera, a silver salt film camera, and a television camera. In the cross-sectional view of the lens, the left side is the object side (front) and the right side is the image side (rear). Further, in the lens cross-sectional view, if i is the order of the lens groups from the object side to the image side, Bi indicates the i-th lens group.

各実施例において、ＳＰは開口絞りである。各実施例において、開口絞りＳＰは、第１レンズ群Ｂ１と第２レンズ群Ｂ２の間に配置されている。 In each embodiment, SP is an aperture stop. In each embodiment, the aperture stop SP is arranged between the first lens group B1 and the second lens group B2.

ＩＰは像面である。ビデオカメラやデジタルカメラの撮像光学系として光学系を使用する際には、像面ＩＰはＣＣＤセンサやＣＭＯＳセンサといった固体撮像素子（光電変換素子）に相当する。銀塩フィルムカメラの撮像光学系として本発明の光学系を使用する際には、像面ＩＰはフィルム面に相当する。 IP is an image plane. When an optical system is used as an image pickup optical system for a video camera or a digital camera, the image plane IP corresponds to a solid-state image pickup element (photoelectric conversion element) such as a CCD sensor or a CMOS sensor. When the optical system of the present invention is used as the image pickup optical system of a silver halide film camera, the image plane IP corresponds to the film plane.

球面収差図においてＦｎｏはＦナンバーであり、ｄ線（波長５８７．６ｎｍ）、ｇ線（波長４３５．８ｎｍ）に対する球面収差を示している。非点収差図においてΔＳはサジタル像面における非点収差量、ΔＭはメリディオナル像面における非点収差量を示している。歪曲収差はｄ線について示している。色収差図ではｇ線における色収差を示している。ωは撮像半画角である。 In the spherical aberration diagram, Fno is an F number and indicates spherical aberration with respect to the d-line (wavelength 587.6 nm) and the g-line (wavelength 435.8 nm). In the astigmatism diagram, ΔS indicates the amount of astigmatism on the sagittal image plane, and ΔM indicates the amount of astigmatism on the meridional image plane. Distortion is shown for line d. The chromatic aberration diagram shows the chromatic aberration on the g-line. ω is the imaging half angle of view.

各実施例では、レンズ断面図中の矢印で示すように、無限遠から近距離へのフォーカシングに際して第２レンズ群Ｂ２が物体側に移動し、隣り合うレンズ群の間隔が変化する。各実施例の光学系において第２レンズ群Ｂ２がフォーカス群に相当する。 In each embodiment, as indicated by the arrows in the lens sectional view, the second lens group B2 moves toward the object during focusing from infinity to a short distance, and the distance between adjacent lens groups changes. In the optical system of each embodiment, the second lens group B2 corresponds to the focus group.

また、各実施例の光学系では、光学系の一部のレンズを防振群として、防振群を光軸と垂直方向の成分を持つ方向に移動させることにより結像位置を変化させることができる。これにより像ぶれ補正を行うことができる。第１レンズ群Ｂ１、第２レンズ群Ｂ２、第３レンズ群Ｂ３のいずれかのレンズ群を防振群としても良いし、特定のレンズ群に含まれる一部のレンズを防振群としても良い。 Further, in the optical system of each embodiment, it is possible to change the imaging position by using a part of the lenses of the optical system as a vibration isolation group and moving the vibration isolation group in a direction having a component in the direction perpendicular to the optical axis. it can. As a result, image blur correction can be performed. Any one of the first lens group B1, the second lens group B2, and the third lens group B3 may be used as the anti-vibration group, or some lenses included in the specific lens group may be used as the anti-vibration group. ..

本発明においては、比較的像側に配置された正の屈折力の第２レンズ群Ｂ２をフォーカス群とすることで、フォーカス群の小型化及び軽量化を実現し、さらに、フォーカシングに際しての色収差や球面収差の変動を低減させている。 In the present invention, by using the second lens group B2 having a positive refractive power relatively arranged on the image side as the focus group, the focus group can be made smaller and lighter, and further, chromatic aberration during focusing can be prevented. The fluctuation of spherical aberration is reduced.

最も物体側に配置された第１レンズ群Ｂ１に含まれるレンズは有効径が大きいため、第１レンズ群Ｂ１をフォーカス群とすると、フォーカス群の大型化及び重量化を招く。一方、最も像側に配置された第３レンズ群Ｂ３においては、軸外光線が光軸から離れた領域を通過するため、第３レンズ群Ｂ３に含まれるレンズは有効径が大きくなりやすい。以上説明したように、フォーカス群の小型化及び軽量化の観点から、第２レンズ群Ｂ２をフォーカス群とすることが好ましい。 Since the lens included in the first lens group B1 arranged on the most object side has a large effective diameter, if the first lens group B1 is set as the focus group, the focus group becomes large and heavy. On the other hand, in the third lens group B3 arranged on the image side most, since the off-axis light rays pass through a region away from the optical axis, the effective diameter of the lens included in the third lens group B3 tends to be large. As described above, from the viewpoint of miniaturization and weight reduction of the focus group, it is preferable to use the second lens group B2 as the focus group.

また、第２レンズ群Ｂ２においては、軸外光線及び軸上光線が光軸から比較的近い領域を通過するため、フォーカシングに際しての軸上色収差や球面収差の変動を小さくすることができる。つまり、フォーカシングに際しての収差変動を抑制するために、第２レンズ群Ｂ２をフォーカス群とすることが好ましい。 Further, in the second lens group B2, since the off-axis light rays and the on-axis light rays pass through a region relatively close to the optical axis, fluctuations in axial chromatic aberration and spherical aberration during focusing can be reduced. That is, in order to suppress aberration fluctuations during focusing, it is preferable to set the second lens group B2 as the focus group.

ここで、光学系における色収差の補正に関連するパラメータとして、アッベ数νｄが知られている。Ｆ線（４８６．１ｎｍ）、Ｃ線（６５６．３ｎｍ）、ｄ線（５８７．６ｎｍ）に対する材料の屈折率をそれぞれＮＦ、ＮＣ、Ｎｄとするとき、アッベ数νｄはそれぞれ、
νｄ＝（Ｎｄ−１）／（ＮＦ−ＮＣ）
で表される。 Here, the Abbe number νd is known as a parameter related to the correction of chromatic aberration in the optical system. When the refractive indexes of the materials with respect to the F line (486.1 nm), C line (656.3 nm), and d line (587.6 nm) are NF, NC, and Nd, respectively, the Abbe number νd is
νd = (Nd-1) / (NF-NC)
It is represented by.

各実施例の光学系は、以下の条件式を満足している。
ＬＤ／ｆ＜１．００…（１）
０．１５＜Ｌ／ｆ＜０．４８…（２） The optical system of each embodiment satisfies the following conditional expression.
LD / f <1.00 ... (1)
0.15 <L / f <0.48 ... (2)

ここで、全系の焦点距離をｆ、第１レンズ群Ｂ１の最も物体側のレンズ面から像面までの光軸上の距離（以下、レンズ全長という）をＬＤ、無限遠に合焦しているときにおける第２レンズ群Ｂ２の最も物体側のレンズ面から像面までの光軸上の距離をＬとする。 Here, the focal length of the entire system is f, the distance on the optical axis from the lens surface on the most object side of the first lens group B1 to the image surface (hereinafter referred to as the total length of the lens) is LD, and the lens is focused at infinity. Let L be the distance on the optical axis from the lens plane on the most object side of the second lens group B2 to the image plane when the lens is in contact with the lens.

条件式（１）は、レンズ全長ＬＤが光学系全系の焦点距離ｆよりも短いことを示している。一般に、レンズ全長の短縮化を図った望遠レンズに搭載される光学系は、焦点距離がレンズ全長ＬＤよりも長くなる。条件式（１）の上限値を上回ってレンズ全長ＬＤが長くなると、光学系が光軸方向に大型化してしまうため好ましくない。 The conditional expression (1) shows that the total lens length LD is shorter than the focal length f of the entire optical system. In general, the optical system mounted on a telephoto lens whose overall lens length is shortened has a focal length longer than that of the lens overall length LD. If the total lens length LD becomes longer than the upper limit of the conditional expression (1), the optical system becomes large in the optical axis direction, which is not preferable.

条件式（２）は、無限遠に合焦しているときにおける第２レンズ群Ｂ２の最も物体側のレンズ面から像面までの光軸上の距離Ｌと、全系の焦点距離ｆの比を規定した条件式である。条件式（２）の下限値を下回ると、フォーカス群である第２レンズ群Ｂ２と第１レンズ群Ｂ１の距離が長くなり過ぎる。その結果、第２レンズ群Ｂ２に入射する軸上光束の光軸からの高さは低くなるが、第２レンズ群Ｂ２に入射する軸外光束の光軸からの高さが高くなりやすい。その結果、第２レンズ群Ｂ２の有効径が大きくなり、光学系の重量の増大を招くため好ましくない。 In the conditional expression (2), the ratio of the distance L on the optical axis from the lens surface on the most object side of the second lens group B2 to the image plane when the lens is in focus at infinity and the focal length f of the entire system. It is a conditional expression that defines. If it falls below the lower limit of the conditional expression (2), the distance between the second lens group B2, which is the focus group, and the first lens group B1 becomes too long. As a result, the height of the on-axis luminous flux incident on the second lens group B2 from the optical axis tends to be low, but the height of the off-axis luminous flux incident on the second lens group B2 from the optical axis tends to be high. As a result, the effective diameter of the second lens group B2 becomes large, which causes an increase in the weight of the optical system, which is not preferable.

また、条件式（２）の上限値を上回ると、フォーカス群である第２レンズ群Ｂ２と第１レンズ群Ｂ１の距離が短くなり過ぎる。その結果、第２レンズ群Ｂ２に入射する軸外光線及び軸上光線の光軸からの高さが高くなり、フォーカシングに際しての球面収差や軸上色収差の変動が増大するため好ましくない。 Further, when the upper limit value of the conditional expression (2) is exceeded, the distance between the second lens group B2 and the first lens group B1 which are the focus groups becomes too short. As a result, the heights of the off-axis light rays and the on-axis light rays incident on the second lens group B2 from the optical axis become high, and fluctuations in spherical aberration and axial chromatic aberration during focusing increase, which is not preferable.

各実施例では以上説明したように、条件式（１）及び（２）を満足するように各要素を適切に設定している。これにより軽量であり、かつ色収差等の収差が良好に補正された光学系を得ることができる。 In each embodiment, as described above, each element is appropriately set so as to satisfy the conditional expressions (1) and (2). As a result, it is possible to obtain an optical system that is lightweight and has well corrected aberrations such as chromatic aberration.

なお、各実施例において、好ましくは、条件式（１）及び（２）の数値範囲を次のように設定するのが良い。
ＬＤ／ｆ＜０．９９５…（１ａ）
０．１８＜Ｌ／ｆ＜０．４７…（２ａ） In each embodiment, it is preferable to set the numerical range of the conditional expressions (1) and (2) as follows.
LD / f <0.995 ... (1a)
0.18 <L / f <0.47 ... (2a)

また、さらに好ましくは、条件式（１）及び（２）の数値範囲を次のように設定するのが良い。
ＬＤ／ｆ＜０．９９０…（１ｂ）
０．２０＜Ｌ／ｆ＜０．４６…（２ｂ） Further, more preferably, it is preferable to set the numerical range of the conditional expressions (1) and (2) as follows.
LD / f <0.990 ... (1b)
0.20 <L / f <0.46 ... (2b)

さらに、各実施例において、次の条件式のうち１つ以上を満足することがより好ましい。
０．１０＜ＥＡ２／ＥＡ１＜０．３９…（３）
０．５０＜ｆ１／ｆ＜１．８０…（４）
０．１５＜ｆ２／ｆ＜０．７０…（５）
０．２０＜ｆＧ１／ｆ＜５．００…（６）
３０．０＜νｄＧ１…（７） Further, in each embodiment, it is more preferable to satisfy one or more of the following conditional expressions.
0.10 <EA2 / EA1 <0.39 ... (3)
0.50 <f1 / f <1.80 ... (4)
0.15 <f2 / f <0.70 ... (5)
0.20 <fG1 / f <5.00 ... (6)
30.0 <νdG1 ... (7)

条件式（３）は、第１レンズ群Ｂ１の最も物体側のレンズ面における有効径ＥＡ１と第２レンズ群Ｂ２の最も物体側のレンズ面における有効径ＥＡ２の比を規定した条件式である。条件式（３）の下限値を下回って、第１レンズ群Ｂ１の最も物体側のレンズ面における有効径ＥＡ１が大きくなると、第１レンズ群Ｂ１における光線の収斂作用を強くする必要が生じる。その結果、第１レンズ群Ｂ１の屈折力が強くなり過ぎて、第１レンズ群Ｂ１において球面収差や軸上色収差が多く発生するため好ましくない。条件式（３）の上限値を上回って、第２レンズ群Ｂ２の最も物体側のレンズ面における有効径ＥＡ２が大きくなると、フォーカス群である第２レンズ群Ｂ２が大型化し、光学系の重量が増大するため好ましくない。 The conditional expression (3) is a conditional expression that defines the ratio of the effective diameter EA1 on the lens surface on the most object side of the first lens group B1 and the effective diameter EA2 on the lens surface on the most object side of the second lens group B2. When the effective diameter EA1 on the lens surface on the most object side of the first lens group B1 becomes larger than the lower limit of the conditional expression (3), it becomes necessary to strengthen the astringent action of the light rays in the first lens group B1. As a result, the refractive power of the first lens group B1 becomes too strong, and a large amount of spherical aberration and axial chromatic aberration occur in the first lens group B1, which is not preferable. When the effective diameter EA2 on the lens surface of the second lens group B2 on the most object side becomes larger than the upper limit of the conditional expression (3), the second lens group B2 which is the focus group becomes larger and the weight of the optical system becomes heavier. It is not preferable because it increases.

条件式（４）は、第１レンズ群Ｂ１の焦点距離ｆ１と全系の焦点距離ｆの比を規定した条件式である。条件式（４）の下限値を下回って第１レンズ群Ｂ１の焦点距離ｆ１が短くなると、第１レンズ群Ｂ１の屈折力が強くなり過ぎる。その結果、第１レンズ群Ｂ１において球面収差や軸上色収差が多く発生するため好ましくない。また、条件式（４）の上限値を上回って第１レンズ群Ｂ１の焦点距離ｆ１が長くなると、第１レンズ群Ｂ１の屈折力が弱くなり過ぎて、レンズ全長が増大するため好ましくない。 The conditional expression (4) is a conditional expression that defines the ratio of the focal length f1 of the first lens group B1 to the focal length f of the entire system. When the focal length f1 of the first lens group B1 becomes shorter than the lower limit of the conditional expression (4), the refractive power of the first lens group B1 becomes too strong. As a result, a large amount of spherical aberration and axial chromatic aberration occur in the first lens group B1, which is not preferable. Further, if the focal length f1 of the first lens group B1 becomes longer than the upper limit of the conditional expression (4), the refractive power of the first lens group B1 becomes too weak and the total lens length increases, which is not preferable.

条件式（５）は、第２レンズ群Ｂ２の焦点距離ｆ２と全系の焦点距離ｆの比を規定した条件式である。条件式（５）の下限値を下回って第２レンズ群Ｂ２の焦点距離ｆ２が短くなると、フォーカス群である第２レンズ群Ｂ２の屈折力が強くなり過ぎる。その結果、フォーカシングに際しての球面収差や軸上色収差の変動が大きくなるため好ましくない。また、条件式（５）の上限値を上回って第２レンズ群Ｂ２の焦点距離ｆ２が長くなると、フォーカス群である第２レンズ群Ｂ２の屈折力が弱くなり過ぎて、フォーカシングに際しての第２レンズ群Ｂ２の移動量が増大する。その結果、光学系が光軸方向に大型化するため好ましくない。 The conditional expression (5) is a conditional expression that defines the ratio between the focal length f2 of the second lens group B2 and the focal length f of the entire system. When the focal length f2 of the second lens group B2 becomes shorter than the lower limit of the conditional expression (5), the refractive power of the second lens group B2, which is the focus group, becomes too strong. As a result, fluctuations in spherical aberration and axial chromatic aberration during focusing become large, which is not preferable. Further, when the focal length f2 of the second lens group B2 becomes longer than the upper limit of the conditional expression (5), the refractive power of the second lens group B2, which is the focus group, becomes too weak, and the second lens at the time of focusing becomes too weak. The amount of movement of group B2 increases. As a result, the optical system becomes large in the optical axis direction, which is not preferable.

条件式（６）は、第１レンズ群Ｂ１に含まれるレンズの中で最も物体側に配置されたレンズＧ１の焦点距離ｆＧ１と全系の焦点距離ｆの比を規定した条件式である。条件式（６）の下限値を下回ってレンズＧ１の焦点距離ｆＧ１が短くなると、レンズＧ１の屈折力が強くなり過ぎる。その結果、レンズＧ１において球面収差が多く発生するため好ましくない。また、条件式（６）の上限値を上回ってレンズＧ１の焦点距離ｆＧ１が長くなると、レンズＧ１の屈折力が弱くなり過ぎる。その結果、レンズＧ１における光線の収斂作用が弱くなり、レンズＧ１よりも像側に配置されるレンズの有効径が大きくなり、光学系の大型化や高重量化を招くため好ましくない。 The conditional expression (6) is a conditional expression that defines the ratio of the focal length fG1 of the lens G1 arranged on the object side most among the lenses included in the first lens group B1 and the focal length f of the entire system. When the focal length fG1 of the lens G1 becomes shorter than the lower limit of the conditional expression (6), the refractive power of the lens G1 becomes too strong. As a result, a large amount of spherical aberration occurs in the lens G1, which is not preferable. Further, when the focal length fG1 of the lens G1 becomes longer than the upper limit value of the conditional expression (6), the refractive power of the lens G1 becomes too weak. As a result, the astringent action of the light beam in the lens G1 becomes weak, the effective diameter of the lens arranged on the image side of the lens G1 becomes large, and the optical system becomes large and heavy, which is not preferable.

条件式（７）は、レンズＧ１の材料のアッベ数νｄＧ１を規定した条件式である。条件式（７）の下限値を下回ってレンズＧ１の材料のアッベ数νｄＧ１が小さくなると、レンズＧ１において軸上色収差や倍率色収差が多く発生するため好ましくない。 The conditional expression (7) is a conditional expression that defines the Abbe number νdG1 of the material of the lens G1. If the Abbe number νdG1 of the material of the lens G1 becomes smaller than the lower limit of the conditional expression (7), a large amount of axial chromatic aberration and lateral chromatic aberration occur in the lens G1, which is not preferable.

好ましくは、条件式（３）〜（７）の数値範囲を次のように設定するのが良い。
０．１２＜ＥＡ２／ＥＡ１＜０．３８…（３ａ）
０．６０＜ｆ１／ｆ＜１．７０…（４ａ）
０．１７＜ｆ２／ｆ＜０．６５…（５ａ）
０．３０＜ｆＧ１／ｆ＜２．５０…（６ａ）
３２．０＜νｄＧ１…（７ａ） Preferably, the numerical range of the conditional expressions (3) to (7) is set as follows.
0.12 <EA2 / EA1 <0.38 ... (3a)
0.60 <f1 / f <1.70 ... (4a)
0.17 <f2 / f <0.65 ... (5a)
0.30 <fG1 / f <2.50 ... (6a)
32.0 <νdG1 ... (7a)

さらに好ましくは、条件式（３）〜（７）の数値範囲を次のように設定するのが良い。
０．１５＜ＥＡ２／ＥＡ１＜０．３８…（３ｂ）
０．７０＜ｆ１／ｆ＜１．６０…（４ｂ）
０．２０＜ｆ２／ｆ＜０．６２…（５ｂ）
０．３５＜ｆＧ１／ｆ＜２．１０…（６ｂ）
３５．０＜νｄＧ１…（７ｂ） More preferably, the numerical range of the conditional expressions (3) to (7) is set as follows.
0.15 <EA2 / EA1 <0.38 ... (3b)
0.70 <f1 / f <1.60 ... (4b)
0.20 <f2 / f <0.62 ... (5b)
0.35 <fG1 / f <2.10 ... (6b)
35.0 <νdG1 ... (7b)

なお、フォーカシングに際して移動する第２レンズ群Ｂ２は、正レンズと負レンズを含むことが好ましい。これにより、フォーカシングに際しての色収差、特に軸上色収差の変動を抑制することができる。 The second lens group B2 that moves during focusing preferably includes a positive lens and a negative lens. As a result, fluctuations in chromatic aberration during focusing, particularly axial chromatic aberration, can be suppressed.

また、第２レンズ群Ｂ２は、２枚以下のレンズから構成されることが好ましい。これによりフォーカス群を軽量化することができ、さらにフォーカス群である第２レンズ群Ｂ２を駆動させるためのメカ機構の小型化及び軽量化を実現することができる。 Further, the second lens group B2 is preferably composed of two or less lenses. As a result, the weight of the focus group can be reduced, and further, the mechanical mechanism for driving the second lens group B2, which is the focus group, can be reduced in size and weight.

さらに、本発明においては、フォーカシングに際して第１レンズ群Ｂ１が不動であることが好ましい。光学系を構成するレンズ群の中で最も物体側に配置される第１レンズ群Ｂ１は、有効径が大きくなり高重量である。重量の大きい第１レンズ群Ｂ１をフォーカシングに際して移動させるためには、大型の駆動機構が必要となり、光学系や光学系を含む撮像装置の高重量化を招くため好ましくない。 Further, in the present invention, it is preferable that the first lens group B1 is immobile during focusing. The first lens group B1 arranged on the object side most among the lens groups constituting the optical system has a large effective diameter and a high weight. In order to move the heavy first lens group B1 at the time of focusing, a large drive mechanism is required, which is not preferable because it causes an increase in the weight of the optical system and the image pickup apparatus including the optical system.

次に、本発明の実施例１から６にそれぞれ対応する数値実施例１から６を示す。各数値実施例において、ｉは物体側からの光学面の順序を示す。ｒｉは第ｉ番目の光学面（第ｉ面）の曲率半径、ｄｉは第ｉ面と第ｉ＋１面との間の間隔、ｎｄｉとνｄｉはそれぞれｄ線に対する第ｉ番目の光学部材の材料の屈折率、アッベ数を示す。レンズ面の間隔変化に関しては、無限遠に合焦しているときのレンズ面の間隔と、最至近距離に合焦しているときのレンズ面の間隔を記載している。 Next, numerical examples 1 to 6 corresponding to Examples 1 to 6 of the present invention are shown. In each numerical embodiment, i indicates the order of the optical planes from the object side. ri is the radius of curvature of the i-th optical plane (i-plane), di is the distance between the i-th plane and the i + 1 plane, and ndi and νdi are the refraction of the material of the i-th optical member with respect to the d line, respectively. Shows the rate and Abbe number. Regarding the change in the distance between the lens surfaces, the distance between the lens surfaces when focusing at infinity and the distance between the lens surfaces when focusing at the closest distance are described.

各実施例において、バックフォーカス（ＢＦ）は、光学系の最も像側の面から像面までの距離を、空気換算長により表したものである。また、各数値実施例における上述した条件式との対応を表１に示す。 In each embodiment, the back focus (BF) represents the distance from the most image-side surface of the optical system to the image surface in terms of air-equivalent length. Table 1 shows the correspondence with the above-mentioned conditional expressions in each numerical example.

なお、各実施例において第１レンズ群Ｂ１の物体側に、レンズを保護するための保護ガラスを配置しても良い。屈折力が極めて弱い保護ガラスは、第１レンズ群Ｂ１に含まれないものとする。 In each embodiment, a protective glass for protecting the lens may be arranged on the object side of the first lens group B1. The protective glass having an extremely weak refractive power is not included in the first lens group B1.

［数値実施例１］
単位 mm
面データ
面番号 r d nd νd 有効径
1 397.368 13.93 1.53172 48.8 141.99
2 -642.420 86.27 141.53
3 134.531 17.79 1.43387 95.1 109.39
4 -659.353 0.62 107.47
5 -534.427 4.45 1.73800 32.3 107.38
6 249.999 15.00 103.06
7 82.885 13.51 1.43387 95.1 95.86
8 217.201 1.00 93.82
9 93.498 5.30 1.61340 44.3 88.99
10 65.350 106.66 81.99
11 137.548 6.80 1.89286 20.4 43.17
12 -147.156 2.40 1.90366 31.3 41.85
13 76.167 8.64 39.48
14(絞り) ∞ (可変) 38.21
15 70.660 1.90 1.85478 24.8 30.85
16 55.067 4.91 1.59522 67.7 30.40
17 803.873 (可変) 30.21
18 87.004 4.28 1.84666 23.9 29.96
19 -95.967 1.62 1.72916 54.7 29.59
20 42.782 4.17 28.35
21 -88.854 1.57 1.91082 35.3 28.40
22 167.200 17.66 29.08
23 118.673 5.16 1.51742 52.4 39.77
24 -141.143 3.16 40.26
25 648.872 7.35 1.73800 32.3 41.33
26 -48.133 1.90 1.92286 18.9 41.56
27 -118.632 103.93 42.40
像面 ∞

各種データ
焦点距離 585.00
Fナンバー 4.12
半画角 2.12
像高 21.64
レンズ全長 475.00
BF 103.93

∞ -0.14倍
d14 33.03 2.00
d17 2.00 33.03

入射瞳位置 951.14
射出瞳位置 -135.47
前側主点位置 106.61
後側主点位置 -481.07

レンズ群データ
群始面焦点距離レンズ構成長前側主点位置後側主点位置
1 1 664.21 273.72 -866.05 -477.77
2 14 148.64 39.84 31.86 -5.25
3 18 -439.82 46.87 -121.45 -223.93
[Numerical Example 1]
Unit mm
Surface data Surface number rd nd νd Effective diameter
1 397.368 13.93 1.53172 48.8 141.99
2 -642.420 86.27 141.53
3 134.531 17.79 1.43387 95.1 109.39
4 -659.353 0.62 107.47
5 -534.427 4.45 1.73800 32.3 107.38
6 249.999 15.00 103.06
7 82.885 13.51 1.43387 95.1 95.86
8 217.201 1.00 93.82
9 93.498 5.30 1.61340 44.3 88.99
10 65.350 106.66 81.99
11 137.548 6.80 1.89286 20.4 43.17
12 -147.156 2.40 1.90366 31.3 41.85
13 76.167 8.64 39.48
14 (Aperture) ∞ (Variable) 38.21
15 70.660 1.90 1.85478 24.8 30.85
16 55.067 4.91 1.59522 67.7 30.40
17 803.873 (variable) 30.21
18 87.004 4.28 1.84666 23.9 29.96
19 -95.967 1.62 1.72916 54.7 29.59
20 42.782 4.17 28.35
21 -88.854 1.57 1.91082 35.3 28.40
22 167.200 17.66 29.08
23 118.673 5.16 1.51742 52.4 39.77
24-141.143 3.16 40.26
25 648.872 7.35 1.73800 32.3 41.33
26 -48.133 1.90 1.92286 18.9 41.56
27 -118.632 103.93 42.40
Image plane ∞

Various data focal length 585.00
F number 4.12
Half angle of view 2.12
Image height 21.64
Lens overall length 475.00
BF 103.93

∞ -0.14 times
d14 33.03 2.00
d17 2.00 33.03

Entrance pupil position 951.14
Exit pupil position -135.47
Front principal point position 106.61
Rear principal point position -481.07

Lens group data group Focal length Lens configuration length Front principal point position Rear principal point position
1 1 664.21 273.72 -866.05 -477.77
2 14 148.64 39.84 31.86 -5.25
3 18 -439.82 46.87 -121.45 -223.93

［数値実施例２］
単位 mm
面データ
面番号 r d nd νd 有効径
1 259.668 15.94 1.54814 45.8 135.37
2 -682.396 56.92 134.68
3 133.258 19.82 1.43387 95.1 105.37
4 -276.467 0.20 103.13
5 -267.867 4.30 1.73800 32.3 103.09
6 199.210 3.10 97.54
7 79.907 16.59 1.43387 95.1 94.34
8 395.372 1.00 92.05
9 65.333 5.00 1.73800 32.3 82.25
10 51.946 57.50 75.14
11 177.323 6.31 1.92286 18.9 52.65
12 -208.413 2.40 1.90366 31.3 51.52
13 91.800 7.53 48.47
14(絞り) ∞ (可変) 47.16
15 95.361 5.53 1.77250 49.6 34.58
16 -157.387 2.05 1.67270 32.1 33.56
17 210.602 (可変) 32.25
18 90.329 4.68 1.84666 23.8 30.85
19 -88.554 1.71 1.67790 55.3 29.94
20 36.768 4.36 27.92
21 -70.456 1.63 1.91082 35.3 27.96
22 214.658 11.01 29.04
23 -520.337 3.99 1.51633 64.1 36.75
24 -77.580 10.16 37.75
25 79.621 10.97 1.61340 44.3 45.83
26 -52.760 1.91 1.92286 18.9 45.99
27 -99.233 75.00 46.90
像面 ∞

各種データ
焦点距離 392.57
Fナンバー 2.90
半画角 3.15
像高 21.64
レンズ全長 371.15
BF 75.00

∞ -0.16倍
d14 39.53 1.00
d17 2.00 40.53

入射瞳位置 485.63
射出瞳位置 -224.30
前側主点位置 363.30
後側主点位置 -317.57

レンズ群データ
群始面焦点距離レンズ構成長前側主点位置後側主点位置
1 1 434.80 189.08 -338.12 -277.05
2 14 177.32 47.11 37.42 -6.38
3 18 1133.91 50.42 426.86 616.09
[Numerical Example 2]
Unit mm
Surface data Surface number rd nd νd Effective diameter
1 259.668 15.94 1.54814 45.8 135.37
2 -682.396 56.92 134.68
3 133.258 19.82 1.43387 95.1 105.37
4-276.467 0.20 103.13
5 -267.867 4.30 1.73800 32.3 103.09
6 199.210 3.10 97.54
7 79.907 16.59 1.43387 95.1 94.34
8 395.372 1.00 92.05
9 65.333 5.00 1.73800 32.3 82.25
10 51.946 57.50 75.14
11 177.323 6.31 1.92286 18.9 52.65
12 -208.413 2.40 1.90366 31.3 51.52
13 91.800 7.53 48.47
14 (Aperture) ∞ (Variable) 47.16
15 95.361 5.53 1.77250 49.6 34.58
16 -157.387 2.05 1.67270 32.1 33.56
17 210.602 (variable) 32.25
18 90.329 4.68 1.84666 23.8 30.85
19 -88.554 1.71 1.67790 55.3 29.94
20 36.768 4.36 27.92
21 -70.456 1.63 1.91082 35.3 27.96
22 214.658 11.01 29.04
23 -520.337 3.99 1.51633 64.1 36.75
24-77.580 10.16 37.75
25 79.621 10.97 1.61340 44.3 45.83
26 -52.760 1.91 1.92286 18.9 45.99
27 -99.233 75.00 46.90
Image plane ∞

Various data focal length 392.57
F number 2.90
Half angle of view 3.15
Image height 21.64
Lens overall length 371.15
BF 75.00

∞ -0.16 times
d14 39.53 1.00
d17 2.00 40.53

Entrance pupil position 485.63
Exit pupil position -224.30
Front principal point position 363.30
Rear principal point position -317.57

Lens group data group Focal length Lens configuration length Front principal point position Rear principal point position
1 1 434.80 189.08 -338.12 -277.05
2 14 177.32 47.11 37.42 -6.38
3 18 1133.91 50.42 426.86 616.09

［数値実施例３］
単位 mm
面データ
面番号 r d nd νd 有効径
1 381.369 11.56 1.53172 48.8 118.70
2 -500.181 61.82 118.33
3 148.541 15.00 1.43387 95.1 96.40
4 -394.609 0.36 94.71
5 -361.695 3.70 1.73800 32.3 94.63
6 308.845 22.72 91.73
7 79.544 10.87 1.43387 95.1 83.35
8 210.448 1.00 81.68
9 75.883 4.90 1.72047 34.7 77.10
10 60.941 80.64 71.98
11 113.172 4.64 1.92286 18.9 40.73
12 984.362 2.50 1.91082 35.3 39.52
13 64.195 10.39 37.45
14(絞り) ∞ (可変) 35.71
15 53.023 1.80 1.91082 35.3 29.50
16 40.373 4.53 1.53775 74.7 28.59
17 1140.560 (可変) 27.97
18 85.792 3.65 1.84666 23.8 26.59
19 -80.860 1.61 1.72916 54.7 25.98
20 41.334 3.17 24.82
21 -78.410 1.50 1.91082 35.3 24.85
22 149.170 22.73 25.47
23 132.930 5.57 1.61340 44.3 39.00
24 -93.848 0.50 39.46
25 423.611 7.08 1.67300 38.1 39.77
26 -48.081 1.80 1.80809 22.8 39.82
27 -253.418 100.00 40.29
像面 ∞

各種データ
焦点距離 489.05
Fナンバー 4.12
半画角 2.53
像高 21.64
レンズ全長 411.08
BF 100.00

∞ -0.14倍
d14 25.05 2.00
d17 2.00 25.05

入射瞳位置 676.66
射出瞳位置 -126.10
前側主点位置 107.93
後側主点位置 -389.05

レンズ群データ
群始面焦点距離レンズ構成長前側主点位置後側主点位置
1 1 516.17 219.71 -532.19 -351.33
2 14 130.99 31.37 23.66 -5.24
3 18 -360.34 47.61 -111.82 -221.95
[Numerical Example 3]
Unit mm
Surface data Surface number rd nd νd Effective diameter
1 381.369 11.56 1.53172 48.8 118.70
2 -500.181 61.82 118.33
3 148.541 15.00 1.43387 95.1 96.40
4 -394.609 0.36 94.71
5 -361.695 3.70 1.73800 32.3 94.63
6 308.845 22.72 91.73
7 79.544 10.87 1.43387 95.1 83.35
8 210.448 1.00 81.68
9 75.883 4.90 1.72047 34.7 77.10
10 60.941 80.64 71.98
11 113.172 4.64 1.92286 18.9 40.73
12 984.362 2.50 1.91082 35.3 39.52
13 64.195 10.39 37.45
14 (Aperture) ∞ (Variable) 35.71
15 53.023 1.80 1.91082 35.3 29.50
16 40.373 4.53 1.53775 74.7 28.59
17 1140.560 (variable) 27.97
18 85.792 3.65 1.84666 23.8 26.59
19 -80.860 1.61 1.72916 54.7 25.98
20 41.334 3.17 24.82
21 -78.410 1.50 1.91082 35.3 24.85
22 149.170 22.73 25.47
23 132.930 5.57 1.61340 44.3 39.00
24 -93.848 0.50 39.46
25 423.611 7.08 1.67300 38.1 39.77
26 -48.081 1.80 1.80809 22.8 39.82
27 -253.418 100.00 40.29
Image plane ∞

Various data focal length 489.05
F number 4.12
Half angle of view 2.53
Image height 21.64
Lens overall length 411.08
BF 100.00

∞ -0.14 times
d14 25.05 2.00
d17 2.00 25.05

Entrance pupil position 676.66
Exit pupil position -126.10
Front principal point position 107.93
Rear principal point position -389.05

Lens group data group Focal length Lens configuration length Front principal point position Rear principal point position
1 1 516.17 219.71 -532.19 -351.33
2 14 130.99 31.37 23.66 -5.24
3 18 -360.34 47.61 -111.82 -221.95

［数値実施例４］
単位 mm
面データ
面番号 r d nd νd 有効径
1 229.599 15.96 1.48749 70.2 133.97
2 -988.019 70.00 133.23
3 144.621 17.38 1.43387 95.1 103.29
4 -340.267 0.30 101.34
5 -340.023 4.45 1.81600 46.6 101.05
6 238.105 8.00 96.97
7 100.345 13.49 1.43387 95.1 93.73
8 570.292 1.00 92.01
9 95.129 5.30 1.67300 38.1 86.31
10 71.718 106.66 80.69
11 163.044 4.96 1.80518 25.4 41.90
12 -213.781 2.00 1.80400 46.6 41.01
13 75.147 7.73 39.11
14(絞り) ∞ (可変) 38.17
15 64.909 1.90 1.90366 31.3 31.04
16 52.933 5.46 1.49700 81.5 30.31
17 1002.162 (可変) 29.44
18 198.056 3.17 1.80809 22.8 28.54
19 -118.676 1.62 1.77250 49.6 28.05
20 63.231 2.36 26.95
21 -148.864 1.57 1.74100 52.6 26.90
22 222.227 17.66 26.86
23 160.615 3.49 1.65412 39.7 28.55
24 -122.891 1.47 28.81
25 -127.293 3.09 1.73800 32.3 28.90
26 -66.303 1.50 1.95906 17.5 29.20
27 -118.632 158.67 29.57
像面 ∞

各種データ
焦点距離 777.00
Fナンバー 5.80
半画角 1.59
像高 21.64
レンズ全長 498.01
BF 158.67

∞ -0.18倍
d14 36.83 2.00
d17 2.00 36.83

入射瞳位置 847.46
射出瞳位置 -92.88
前側主点位置 -775.65
後側主点位置 -618.34

レンズ群データ
群始面焦点距離レンズ構成長前側主点位置後側主点位置
1 1 722.87 249.48 -974.00 -509.76
2 14 170.40 44.19 35.13 -6.31
3 18 -202.16 35.93 -31.23 -73.58
[Numerical Example 4]
Unit mm
Surface data Surface number rd nd νd Effective diameter
1 229.599 15.96 1.48749 70.2 133.97
2 -988.019 70.00 133.23
3 144.621 17.38 1.43387 95.1 103.29
4-340.267 0.30 101.34
5 -340.023 4.45 1.81600 46.6 101.05
6 238.105 8.00 96.97
7 100.345 13.49 1.43387 95.1 93.73
8 570.292 1.00 92.01
9 95.129 5.30 1.67300 38.1 86.31
10 71.718 106.66 80.69
11 163.044 4.96 1.80518 25.4 41.90
12 -213.781 2.00 1.80400 46.6 41.01
13 75.147 7.73 39.11
14 (Aperture) ∞ (Variable) 38.17
15 64.909 1.90 1.90366 31.3 31.04
16 52.933 5.46 1.49700 81.5 30.31
17 1002.162 (variable) 29.44
18 198.056 3.17 1.80809 22.8 28.54
19 -118.676 1.62 1.77250 49.6 28.05
20 63.231 2.36 26.95
21 -148.864 1.57 1.74100 52.6 26.90
22 222.227 17.66 26.86
23 160.615 3.49 1.65412 39.7 28.55
24-122.891 1.47 28.81
25 -127.293 3.09 1.73800 32.3 28.90
26 -66.303 1.50 1.95906 17.5 29.20
27 -118.632 158.67 29.57
Image plane ∞

Various data focal length 777.00
F number 5.80
Half angle of view 1.59
Image height 21.64
Lens overall length 498.01
BF 158.67

∞ -0.18 times
d14 36.83 2.00
d17 2.00 36.83

Entrance pupil position 847.46
Exit pupil position -92.88
Front principal point position -775.65
Rear principal point position -618.34

Lens group data group Focal length Lens configuration length Front principal point position Rear principal point position
1 1 722.87 249.48 -974.00 -509.76
2 14 170.40 44.19 35.13 -6.31
3 18 -202.16 35.93 -31.23 -73.58

［数値実施例５］
単位 mm
面データ
面番号 r d nd νd 有効径
1 192.312 13.69 1.54814 45.8 100.87
2 -380.823 19.00 100.18
3 108.633 17.13 1.43387 95.1 85.97
4 -213.766 0.41 83.59
5 -205.792 3.30 1.73800 32.3 83.26
6 172.454 5.00 78.67
7 59.218 13.09 1.43387 95.1 74.39
8 208.094 1.00 72.30
9 48.647 4.50 1.73800 32.3 64.18
10 38.810 37.98 57.87
11 156.114 4.20 1.92286 18.9 42.43
12 -300.692 2.10 1.88300 40.8 41.55
13 59.296 5.27 38.84
14(絞り) ∞ (可変) 38.38
15 58.603 5.30 1.59522 67.7 32.86
16 -142.767 1.70 1.78472 25.7 32.12
17 -727.435 (可変) 31.40
18 165.812 4.22 1.84666 23.9 29.74
19 -72.258 1.50 1.62299 58.2 28.93
20 37.836 4.11 26.85
21 -63.355 1.50 1.80400 46.6 26.89
22 104.964 12.85 28.08
23 164.943 5.43 1.51633 64.1 39.14
24 -91.658 0.20 40.03
25 99.528 9.03 1.61340 44.3 42.03
26 -51.084 1.80 1.92286 18.9 42.23
27 -97.017 76.35 43.09
像面 ∞

各種データ
焦点距離 292.53
Fナンバー 2.90
半画角 4.23
像高 21.64
レンズ全長 273.92
BF 76.35

∞ -0.17倍
d14 21.27 2.00
d17 1.00 22.27

入射瞳位置 284.51
射出瞳位置 -117.44
前側主点位置 135.47
後側主点位置 -216.18

レンズ群データ
群始面焦点距離レンズ構成長前側主点位置後側主点位置
1 1 417.38 121.40 -402.53 -254.38
2 14 100.93 28.27 21.29 -4.26
3 18 -730.88 40.64 -235.71 -397.49
[Numerical Example 5]
Unit mm
Surface data Surface number rd nd νd Effective diameter
1 192.312 13.69 1.54814 45.8 100.87
2 -380.823 19.00 100.18
3 108.633 17.13 1.43387 95.1 85.97
4 -213.766 0.41 83.59
5 -205.792 3.30 1.73800 32.3 83.26
6 172.454 5.00 78.67
7 59.218 13.09 1.43387 95.1 74.39
8 208.094 1.00 72.30
9 48.647 4.50 1.73800 32.3 64.18
10 38.810 37.98 57.87
11 156.114 4.20 1.92286 18.9 42.43
12 -300.692 2.10 1.88300 40.8 41.55
13 59.296 5.27 38.84
14 (Aperture) ∞ (Variable) 38.38
15 58.603 5.30 1.59522 67.7 32.86
16 -142.767 1.70 1.78472 25.7 32.12
17 -727.435 (variable) 31.40
18 165.812 4.22 1.84666 23.9 29.74
19 -72.258 1.50 1.62299 58.2 28.93
20 37.836 4.11 26.85
21 -63.355 1.50 1.80400 46.6 26.89
22 104.964 12.85 28.08
23 164.943 5.43 1.51633 64.1 39.14
24-91.658 0.20 40.03
25 99.528 9.03 1.61340 44.3 42.03
26 -51.084 1.80 1.92286 18.9 42.23
27 -97.017 76.35 43.09
Image plane ∞

Various data
Focal length 292.53
F number 2.90
Half angle of view 4.23
Image height 21.64
Lens overall length 273.92
BF 76.35

∞ -0.17 times
d14 21.27 2.00
d17 1.00 22.27

Entrance pupil position 284.51
Exit pupil position -117.44
Front principal point position 135.47
Rear principal point position -216.18

Lens group data group Focal length Lens configuration length Front principal point position Rear principal point position
1 1 417.38 121.40 -402.53 -254.38
2 14 100.93 28.27 21.29 -4.26
3 18 -730.88 40.64 -235.71 -397.49

［数値実施例６］
単位 mm
面データ
面番号 r d nd νd 有効径
1 142.560 10.00 1.48749 70.2 97.09
2 588.718 2.00 96.28
3 66.994 20.00 1.43387 95.1 91.43
4 692.391 0.20 89.06
5 57.981 3.20 1.91082 35.3 76.20
6 43.350 16.47 1.59522 67.7 68.60
7 123.299 3.56 64.21
8 417.796 3.20 1.85478 24.8 63.40
9 50.658 6.62 55.21
10 44.368 6.95 1.92286 18.9 52.24
11 98.042 2.50 1.77250 49.6 50.66
12 31.572 9.99 43.47
13(絞り) ∞ (可変) 43.08
14 57.925 1.80 1.72047 34.7 36.31
15 23.797 8.72 1.76385 48.5 33.68
16 113.771 (可変) 32.29
17 52.520 1.75 1.95375 32.3 30.04
18 33.155 5.92 28.35
19 -167.695 6.06 1.61340 44.3 28.97
20 -23.885 1.20 1.71300 53.9 29.54
21 -806.112 3.12 32.17
22 93.512 7.88 1.51633 64.1 35.83
23 -42.724 5.31 36.47
24 -70.650 1.80 1.59522 67.7 36.45
25 35.915 7.04 1.72916 54.7 38.36
26 -2902.542 38.50 38.47
像面 ∞

各種データ
焦点距離 200.00
Fナンバー 2.06
半画角 6.17
像高 21.64
レンズ全長 196.01
BF 38.50

∞ -0.12倍
d13 19.71 1.48
d16 2.50 20.73

入射瞳位置 150.42
射出瞳位置 -71.71
前側主点位置 -12.54
後側主点位置 -161.50

レンズ群データ
群始面焦点距離レンズ構成長前側主点位置後側主点位置
1 1 308.98 84.69 -241.16 -172.71
2 14 123.71 10.52 -4.73 -10.32
3 17 -599.35 40.08 -83.39 -130.49 [Numerical Example 6]
Unit mm
Surface data Surface number rd nd νd Effective diameter
1 142.560 10.00 1.48749 70.2 97.09
2 588.718 2.00 96.28
3 66.994 20.00 1.43387 95.1 91.43
4 692.391 0.20 89.06
5 57.981 3.20 1.91082 35.3 76.20
6 43.350 16.47 1.59522 67.7 68.60
7 123.299 3.56 64.21
8 417.796 3.20 1.85478 24.8 63.40
9 50.658 6.62 55.21
10 44.368 6.95 1.92286 18.9 52.24
11 98.042 2.50 1.77250 49.6 50.66
12 31.572 9.99 43.47
13 (Aperture) ∞ (Variable) 43.08
14 57.925 1.80 1.72047 34.7 36.31
15 23.797 8.72 1.76385 48.5 33.68
16 113.771 (variable) 32.29
17 52.520 1.75 1.95375 32.3 30.04
18 33.155 5.92 28.35
19 -167.695 6.06 1.61340 44.3 28.97
20 -23.885 1.20 1.71300 53.9 29.54
21 -806.112 3.12 32.17
22 93.512 7.88 1.51633 64.1 35.83
23 -42.724 5.31 36.47
24-70.650 1.80 1.59522 67.7 36.45
25 35.915 7.04 1.72916 54.7 38.36
26 -2902.542 38.50 38.47
Image plane ∞

Various data focal length 200.00
F number 2.06
Half angle of view 6.17
Image height 21.64
Lens overall length 196.01
BF 38.50

∞ -0.12 times
d13 19.71 1.48
d16 2.50 20.73

Entrance pupil position 150.42
Exit pupil position -71.71
Front principal point position -12.54
Rear principal point position -161.50

Lens group data group Focal length Lens configuration length Front principal point position Rear principal point position
1 1 308.98 84.69 -241.16 -172.71
2 14 123.71 10.52 -4.73 -10.32
3 17 -599.35 40.08 -83.39 -130.49

次に、本発明の光学系を撮像光学系として用いたデジタルスチルカメラ（撮像装置）の実施例について、図１３を用いて説明する。図１３において、１０はカメラ本体、１１は実施例１乃至６で説明したいずれかの光学系によって構成された撮影光学系である。１２はカメラ本体に内蔵され、撮影光学系１１によって形成された被写体像を受光するＣＣＤセンサやＣＭＯＳセンサ等の固体撮像素子（光電変換素子）である。 Next, an example of a digital still camera (imaging apparatus) using the optical system of the present invention as an imaging optical system will be described with reference to FIG. In FIG. 13, 10 is a camera body, and 11 is a photographing optical system configured by any of the optical systems described in Examples 1 to 6. Reference numeral 12 denotes a solid-state image sensor (photoelectric conversion element) such as a CCD sensor or a CMOS sensor that is built in the camera body and receives a subject image formed by the photographing optical system 11.

このように本発明の光学系をデジタルスチルカメラ等の撮像装置に適用することにより、軽量であり、かつ色収差等の収差が良好に補正された撮像装置を得ることができる。 By applying the optical system of the present invention to an imaging device such as a digital still camera in this way, it is possible to obtain an imaging device that is lightweight and has chromatic aberration and other aberrations satisfactorily corrected.

Ｂ１第１レンズ群
Ｂ２第２レンズ群
Ｂ３第３レンズ群
ＳＰ開口絞り
ＩＰ像面 B1 1st lens group B2 2nd lens group B3 3rd lens group SP Aperture aperture IP image plane

本発明の光学系は、物体側より像側へ順に配置された、正の屈折力の第１レンズ群、正の屈折力の第２レンズ群、第３レンズ群から構成され、フォーカシングに際して前記第２レンズ群が移動し、隣り合うレンズ群の間隔が変化する光学系であって、無限遠に合焦しているときにおける前記第２レンズ群の最も物体側のレンズ面から像面までの光軸上の距離をＬ、前記光学系の焦点距離をｆ、前記第１レンズ群の焦点距離をｆ１、前記第１レンズ群に含まれるレンズの中で最も物体側に配置されたレンズＧ１の材料のアッベ数をνｄＧ１としたとき、
０．１５＜Ｌ／ｆ＜０．４８
０．５０＜ｆ１／ｆ≦１．５４５
３０．０＜νｄＧ１
なる条件式を満足することを特徴とする。 The optical system of the present invention, disposed in order from the object side to the image side, a first lens unit having a positive refractive power, a second lens unit having a positive refractive power, a third lens group, wherein during focusing first 2 lens groups are moved, an optical system that interval group adjacent lens changes, to the image plane from the lens surface on the most object side of the second lens group in a state of focusing on the far infinite The distance on the optical axis is L, the focal distance of the optical system is f , the focal distance of the first lens group is f1, and the lens G1 arranged on the object side most among the lenses included in the first lens group. When the Abbe number of the material is νdG1 ,
0.15 <L / f <0.48
0.50 <f1 / f ≦ 1.545
30.0 <νdG1
It is characterized in that it satisfies the conditional expression.

Claims

Focusing is composed of a first lens group having a positive refractive power, a second lens group having a positive refractive power, and a third lens group having a positive or negative refractive power arranged in order from the object side to the image side. This is an optical system in which the second lens group moves and the distance between adjacent lens groups changes.
The distance on the optical axis from the lens surface on the most object side of the optical system to the image plane is LD, and when the second lens group is in focus at infinity, the distance from the lens surface on the most object side to the image plane of the second lens group is When the distance on the optical axis is L and the focal length of the optical system is f,
LD / f <1.00
0.15 <L / f <0.48
An optical system characterized by satisfying the conditional expression.

When the effective diameter of the first lens group on the most object-side lens surface is EA1, and the effective diameter of the second lens group on the most object-side lens surface is EA2,
0.10 <EA2 / EA1 <0.39
The optical system according to claim 1, wherein the optical system satisfies the conditional expression.

When the focal length of the first lens group is f1,
0.50 <f1 / f <1.80
The optical system according to claim 1 or 2, wherein the conditional expression is satisfied.

When the focal length of the second lens group is f2,
0.15 <f2 / f <0.70
The optical system according to any one of claims 1 to 3, wherein the conditional expression is satisfied.

When the focal length of the lens G1 arranged closest to the object side among the lenses included in the first lens group is fG1.
0.20 <fG1 / f <5.00
The optical system according to any one of claims 1 to 4, wherein the conditional expression is satisfied.

When the Abbe number of the material of the lens G1 is νdG1,
30.0 <νdG1
The optical system according to claim 5, wherein the conditional expression is satisfied.

The optical system according to any one of claims 1 to 6, wherein the second lens group includes a positive lens and a negative lens.

The optical system according to any one of claims 1 to 7, wherein the second lens group is composed of two or less lenses.

The optical system according to any one of claims 1 to 8, wherein an aperture diaphragm is arranged between the first lens group and the second lens group.

An image pickup apparatus comprising the optical system according to any one of claims 1 to 9 and an image pickup element that receives an image formed by the optical system.