JP2013142782A5

JP2013142782A5 -

Info

Publication number: JP2013142782A5
Application number: JP2012003024A
Authority: JP
Filing date: 2012-01-11
Publication date: 2015-02-26
Anticipated expiration: 2032-01-11

Description

Optical system and imaging apparatus having the same

本発明は、光学系に関し、例えば銀塩フィルム用カメラ、デジタルスチルカメラ、ビデオカメラ、デジタルビデオカメラ、ＴＶカメラ等の撮像装置に用いられる撮影光学系に好適なものである。 The present invention relates to an optical system, and is suitable for, for example, a photographing optical system used in an imaging apparatus such as a silver salt film camera, a digital still camera, a video camera, a digital video camera, and a TV camera.

近年、デジタルカメラやビデオカメラ等の撮像装置に用いられている撮像素子は高画素化（高密度化）されている。このような高画素の撮像素子を備える撮像装置で用いる撮影光学系には、諸収差が良好に補正され、画面周辺まで広い範囲にわたり高い光学性能を有していることが要求されている。 In recent years, image pickup elements used in image pickup apparatuses such as digital cameras and video cameras have been increased in the number of pixels (higher density). A photographing optical system used in an image pickup apparatus including such a high-pixel image pickup device is required to have various aberrations corrected well and to have high optical performance over a wide range up to the periphery of the screen.

また、より高精細な画像を得るために、撮影時の手ぶれ等の振動の影響による画像の劣化を抑制する機能、所謂防振機構を有すること等が求められている。防振機構としては、光学系の一部のレンズ群を光軸に対して垂直方向の成分を含む方向に移動させることによって手ぶれ等に起因する像位置の変動を補正する方式が知られている。この防振機構は、望遠レンズの他、広画角レンズや標準型レンズ等の撮影光学系にも多く用いられている（特許文献１、２）。 In addition, in order to obtain a higher-definition image, it is required to have a function of suppressing image degradation due to the influence of vibration such as camera shake during photographing, a so-called vibration-proof mechanism. As an anti-vibration mechanism, there is known a method of correcting a change in image position caused by camera shake or the like by moving a part of a lens group of an optical system in a direction including a component perpendicular to the optical axis. . This anti-vibration mechanism is often used for photographing optical systems such as wide-angle lenses and standard lenses in addition to telephoto lenses (Patent Documents 1 and 2).

特許文献１では物体側から順に負の屈折力を有するレンズ群ＧＦと正の屈折力を有するレンズ群ＧＬで構成される広角レンズを開示している。そしてレンズ群ＧＬを構成する最も像側の２枚の正レンズを光軸上の点を中心に回転移動させて防振を行うことを開示している。 Patent Document 1 discloses a wide-angle lens including a lens group GF having a negative refractive power and a lens group GL having a positive refractive power in order from the object side. It discloses that the two image-side positive lenses constituting the lens group GL are rotationally moved around a point on the optical axis to perform image stabilization.

特許文献２では、開口絞りに対して対称的な構成を持つガウスタイプのレンズ系において開口絞りより物体側に正の屈折力の第１レンズ群、像側に正の屈折力の第２レンズ群を配置している。そして第２レンズ群全体を光軸に対して略垂直方向に移動させて防振を行うことを開示している。 In Patent Document 2, in a Gauss type lens system having a symmetric configuration with respect to the aperture stop, a first lens group having a positive refractive power on the object side from the aperture stop, and a second lens group having a positive refractive power on the image side. Is arranged. It discloses that the entire second lens group is moved in a direction substantially perpendicular to the optical axis for image stabilization.

特開平８−２２０４２７号公報JP-A-8-220427 特開平８−２２０４２４号公報JP-A-8-220424

撮影光学系において良好なる画像を得るための一手段として防振機能を用いることは有効である。しかしながら防振機能を設けて光学系（撮影光学系）が振動したときの像ぶれを補正するには、単に光路中に防振機能を設けるのではなく、撮影光学系の適切なる位置に配置することが防振において良好なる光学性能を得るのに重要になってくる。 It is effective to use the image stabilization function as one means for obtaining a good image in the photographing optical system. However, in order to correct image blur when the optical system (shooting optical system) vibrates by providing an image stabilization function, it is not simply provided with an image stabilization function in the optical path, but is disposed at an appropriate position in the image capturing optical system. This is important for obtaining good optical performance in image stabilization.

防振機能を用いて光学系が振動したときの像ぶれを、光学性能を良好に維持しつつ、補正するには、第１サブレンズ群のレンズ構成及び第１サブレンズ群の前後のレンズ構成等を適切に設定することが重要である。特にこれらの要件は防振の際の駆動機構の負担を少なくしつつ、画面全体にわたり高い光学性能を得るために重要である。これらの要素が不適切であると駆動機構が大型化し、また防振時に偏心収差が多く発生し、光学性能が大きく低下してくる。 An image blur when the optical system with a vibration reduction function vibrates while maintaining the optical performance favorably, to correction, lens configuration of the front and rear of the first sub-lens lens configuration and the first sub-lens group of the group It is important to set these appropriately. In particular, these requirements are important in order to obtain high optical performance over the entire screen while reducing the burden on the drive mechanism during image stabilization. If these elements are inappropriate, the drive mechanism becomes large, and a large amount of decentration aberrations occur during image stabilization, resulting in a significant decrease in optical performance.

特許文献１では、最も像面側に近い位置に配置した２つのレンズを第１サブレンズ群としている。このため、第１サブレンズ群に入射する軸外光線の主光線の入射位置が高くなり、レンズ径が大きくなり、また防振時の収差補正が困難になる傾向がある。 In Patent Document 1, two lenses arranged at a position closest to the image plane side are used as a first sub- lens group. For this reason, the incident position of the principal ray of the off-axis ray incident on the first sub- lens group is increased, the lens diameter is increased, and aberration correction at the time of image stabilization tends to be difficult.

特許文献２に開示されたガウス型のレンズ系では、第２レンズ群全体を移動させて防振を行っているため、第１サブレンズ群の駆動機構への負荷が大きくなる傾向があった。また、軸上光線において防振時のコマ収差の変動が大きく、光学性能が低下する傾向があった。 In the Gauss type lens system disclosed in Patent Document 2, since the entire second lens group is moved for image stabilization, the load on the drive mechanism of the first sub- lens group tends to increase. In addition, coma aberration variation during image stabilization is large for axial rays, and optical performance tends to deteriorate.

本発明は、防振時においても光学性能を良好に維持することができ、防振時における防振機構の負担が少なく、防振を容易に行うことができる光学系の提供を目的とする。 An object of the present invention is to provide an optical system capable of maintaining good optical performance even during vibration isolation, reducing the burden on the vibration isolation mechanism during vibration isolation, and easily performing vibration isolation.

本発明の光学系は、最も物体側に配置された前側レンズ群と、前記前側レンズ群の像側に隣接して配置された中間レンズ群と、前記中間レンズ群の像側に隣接して配置された後側レンズ群より構成される光学系であって、
前記中間レンズ群は、光軸に対して垂直方向の成分を持つ方向に移動して結像位置を光軸に対して垂直方向に移動させる第１サブレンズ群と、前記第１サブレンズ群に隣接して配置され、前記第１サブレンズ群の屈折力と異符号の屈折力を有する第２サブレンズ群により構成されており、
前記第２サブレンズ群は単レンズまたは接合レンズにより構成されており、
前記後側レンズ群の中で最も物体側のレンズ面は凹形状であり、前記後側レンズ群の中で最も像側のレンズ面は凸形状であり、
前記第１サブレンズ群の焦点距離をｆｉｓ、前記第２サブレンズ群の焦点距離をｆｃとするとき、
０．３＜｜ｆｃ／ｆｉｓ｜＜３．５
なる条件式を満足すること
を特徴としている。 The optical system of the present invention is arranged adjacent to the front lens group disposed closest to the object side, the intermediate lens group disposed adjacent to the image side of the front lens group, and the image side of the intermediate lens group. an optical system that consists from rear lens group which is,
The intermediate lens group includes a first sub lens group that moves in a direction having a component perpendicular to the optical axis and moves an imaging position in a direction perpendicular to the optical axis, and the first sub lens group. It is composed of a second sub lens group that is arranged adjacent to each other and has a refractive power different from that of the first sub lens group,
The second sub lens group is configured by a single lens or a cemented lens,
The lens surface closest to the object side in the rear lens group is a concave shape, a lens surface on the most image side in the rear lens group is convex,
When the focal length of the first sub lens group is fis and the focal length of the second sub lens group is fc,
0.3 <| fc / fis | <3.5
It satisfies the following conditional expression.

本発明によれば、防振時においても光学性能を良好に維持することができ、防振時における防振機構の負担が少なく、防振を容易に行うことができる光学系が得られる。 According to the present invention, it is possible to obtain an optical system capable of maintaining good optical performance even during vibration isolation, reducing the burden on the vibration isolation mechanism during vibration isolation, and easily performing vibration isolation.

実施例１のレンズ断面図Lens sectional view of Example 1 実施例１の縦収差図Longitudinal aberration diagram of Example 1 （Ａ）、（Ｂ）本発明の実施例１の基準状態と０．３°の防振補正をした時の横収差図(A), (B) Lateral aberration diagrams when the reference state of Example 1 of the present invention and the image stabilization correction of 0.3 ° are performed. 実施例２のレンズ断面図Lens sectional view of Example 2 実施例２の縦収差図Longitudinal aberration diagram of Example 2 （Ａ）、（Ｂ）本発明の実施例２の基準状態と０．３°の防振補正をした時の横収差図(A), (B) Lateral aberration diagram when the reference state of Example 2 of the present invention and the image stabilization correction of 0.3 ° are performed 実施例３のレンズ断面図Lens sectional view of Example 3 実施例３の縦収差図Longitudinal aberration diagram of Example 3 （Ａ）、（Ｂ）本発明の実施例３の基準状態と０．３°の防振補正をした時の横収差図(A), (B) Lateral aberration diagram when the reference state of Example 3 of the present invention and the image stabilization correction of 0.3 ° are performed. 実施例４のレンズ断面図Lens sectional view of Example 4 実施例４の縦収差図Longitudinal aberration diagram of Example 4 （Ａ）、（Ｂ）本発明の実施例４の基準状態と０．３°の防振補正をした時の横収差図(A), (B) Lateral aberration diagram when the reference state of Example 4 of the present invention and the image stabilization correction of 0.3 ° are performed. 実施例５のレンズ断面図Lens sectional view of Example 5 実施例５の縦収差図Longitudinal aberration diagram of Example 5 （Ａ）、（Ｂ）本発明の実施例５の基準状態と０．３°の防振補正をした時の横収差図(A), (B) Lateral aberration diagram when the reference state of Example 5 of the present invention and the image stabilization correction of 0.3 ° are performed. 本発明の撮像装置の要部概略図Schematic diagram of main parts of an imaging apparatus of the present invention

以下に、本発明の好ましい実施の形態を、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、最も物体側に配置された前側レンズ群と、前記前側レンズ群の像側に隣接して配置された中間レンズ群と、前記中間レンズ群の像側に隣接して配置された後側レンズ群により構成されている。 Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The optical system of the present invention is arranged adjacent to the front lens group disposed closest to the object side, the intermediate lens group disposed adjacent to the image side of the front lens group, and the image side of the intermediate lens group. The rear lens group is made up of.

中間レンズ群は、光軸に対して垂直方向の成分を持つ方向に移動して結像位置を光軸に対して垂直方向に移動する第１サブレンズ群と、第１サブレンズ群に隣接して配置され、第１サブレンズ群と異符号の屈折力の第２サブレンズ群により構成されている。第２サブレンズ群は単レンズまたは接合レンズにより構成されている。後側レンズ群の最も物体側のレンズ面は凹形状であり、後側レンズ群の最も像側のレンズ面は凸形状である。 The intermediate lens group is adjacent to the first sub- lens group and the first sub- lens group that moves in a direction having a component perpendicular to the optical axis and moves the imaging position in the direction perpendicular to the optical axis. The first sub- lens group and the second sub- lens group having a different refractive power from the first sub- lens group. The second sub lens group includes a single lens or a cemented lens. A lens surface closest to the object side in the rear lens group is concave, the lens surface on the most image side of the rear lens group is convex.

図１は本発明の実施例１の光学系のレンズ断面図、図２は実施例１の光学系の縦収差図、図３（Ａ）、（Ｂ）は本発明の実施例１の光学系の基準状態と０．３°の防振補正をしたときの横収差図である。図４は本発明の実施例２の光学系のレンズ断面図、図５は実施例２の光学系の縦収差図、図６（Ａ）、（Ｂ）は本発明の実施例２の光学系の基準状態と０．３°の防振補正をしたときの横収差図である。図７は本発明の実施例３の光学系のレンズ断面図、図８は実施例３の光学系の縦収差図、図９（Ａ）、（Ｂ）は本発明の実施例３の光学系の基準状態と０．３°の防振補正をしたときの横収差図である。 1 is a cross-sectional view of a lens of an optical system according to Example 1 of the present invention, FIG. 2 is a longitudinal aberration diagram of the optical system according to Example 1, and FIGS. 3A and 3B are optical systems according to Example 1 of the present invention. FIG. 6 is a transverse aberration diagram when the reference state is corrected and the image stabilization is 0.3 °. 4 is a lens cross-sectional view of the optical system of Example 2 of the present invention, FIG. 5 is a longitudinal aberration diagram of the optical system of Example 2, and FIGS. 6A and 6B are optical systems of Example 2 of the present invention. FIG. 6 is a transverse aberration diagram when the reference state is corrected and the image stabilization is 0.3 °. 7 is a lens cross-sectional view of the optical system of Example 3 of the present invention, FIG. 8 is a longitudinal aberration diagram of the optical system of Example 3, and FIGS. 9A and 9B are optical systems of Example 3 of the present invention. FIG. 6 is a transverse aberration diagram when the reference state is corrected and the image stabilization is 0.3 °.

図１０は本発明の実施例４の光学系のレンズ断面図、図１１は実施例４の光学系の縦収差図、図１２（Ａ）、（Ｂ）は本発明の実施例４の光学系の基準状態と０．３°の防振補正をしたときの横収差図である。図１３は本発明の実施例５の光学系のレンズ断面図、図１４は実施例５の光学系の縦収差図、図１５（Ａ）、（Ｂ）は本発明の実施例５の光学系の基準状態と０．３°の防振補正をしたときの横収差図である。図１６は本発明の広角レンズを備える一眼レフカメラ(撮像装置)の要部概略図である。 10 is a sectional view of a lens of an optical system according to Example 4 of the present invention, FIG. 11 is a longitudinal aberration diagram of the optical system according to Example 4, and FIGS. 12A and 12B are optical systems according to Example 4 of the present invention. FIG. 6 is a transverse aberration diagram when the reference state is corrected and the image stabilization is 0.3 °. FIG. 13 is a lens cross-sectional view of the optical system of Example 5 of the present invention, FIG. 14 is a longitudinal aberration diagram of the optical system of Example 5, and FIGS. 15A and 15B are optical systems of Example 5 of the present invention. FIG. 6 is a transverse aberration diagram when the reference state is corrected and the image stabilization is 0.3 °. FIG. 16 is a schematic diagram of a main part of a single-lens reflex camera (imaging device) including the wide-angle lens of the present invention.

各実施例の光学系は、一眼レフカメラ、デジタルスチルカメラ、ビデオカメラ等の撮像装置に用いられる撮影光学系である。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。レンズ断面図において、ＬＡは光学系（撮影レンズ）、ＬＦは前側レンズ群、ＬＭは中間レンズ群、ＬＲは後側レンズ群である。Ｌｉｓは第１サブレンズ群、Ｌｃは第２サブレンズ群である。 The optical system of each embodiment is a photographing optical system used in an imaging apparatus such as a single-lens reflex camera, a digital still camera, or a video camera. In the lens cross-sectional view, the left side is the object side (front), and the right side is the image side (rear). In the lens cross-sectional view, LA is an optical system (photographing lens), LF is a front lens group, LM is an intermediate lens group, and LR is a rear lens group. Lis is a first sub lens group, and Lc is a second sub lens group.

ＳＰは絞り（開口絞り）である。ＳＰ２は副絞りである。ＩＰは像面であり、ビデオカメラやデジタルスチルカメラの撮影光学系として使用する際にはＣＣＤセンサやＣＭＯＳセンサなどの固体撮像素子（光電変換素子）の撮像面が、銀塩フィルム用カメラのときはフィルム面に相当する。 SP is a stop (aperture stop). SP2 is a sub-aperture. IP is an image plane. When the imaging optical system of a video camera or digital still camera is used, the imaging surface of a solid-state imaging device (photoelectric conversion device) such as a CCD sensor or a CMOS sensor is a silver salt film camera. Corresponds to the film surface.

それぞれの縦収差図は、左から順に、球面収差、非点収差、歪曲、倍率色収差を表している。球面収差と倍率色収差を示す図において、実線はｄ線（５８７．６ｎｍ）、二点破線はｇ線（４３５．８ｎｍ）を表している。また、非点収差を示す図において、実線はｄ線のサジタル方向ΔＳ、破線はｄ線のメリディオナル方向ΔＭを表している。また、歪曲を示す図は、ｄ線における歪曲を表している。横収差図において、実線はｄ線のメリディオナル方向ΔＭ、破線はｄ線のサジタル方向ΔＳ、二点破線はｇ線のメリディオナル方向ｇΔＭを表している。ＦｎｏはＦナンバー、ωは半画角、ｈｇｔは像高である。 Each longitudinal aberration diagram shows spherical aberration, astigmatism, distortion, and lateral chromatic aberration in order from the left. In the diagrams showing spherical aberration and lateral chromatic aberration, the solid line represents the d-line (587.6 nm), and the two-dot broken line represents the g-line (435.8 nm). In the diagram showing astigmatism, the solid line represents the sagittal direction ΔS of the d line, and the broken line represents the meridional direction ΔM of the d line. Moreover, the figure which shows distortion represents the distortion in d line | wire. In the lateral aberration diagram, the solid line represents the meridional direction ΔM of the d line, the broken line represents the sagittal direction ΔS of the d line, and the two-dot broken line represents the meridional direction gΔM of the g line. Fno is the F number, ω is the half angle of view, and hgt is the image height.

本発明の光学系は、最も像側に正の屈折力の後側レンズ群ＬＲを配置し、その物体側に隣接して、二つのサブレンズ群Ｌｉｓ、Ｌｃより成る中間レンズ群ＬＭを配置し、更にその中間レンズ群ＬＭの物体側に隣接して前側レンズ群ＬＦを配置して構成されている。本発明は、単焦点距離の光学系である。 In the optical system of the present invention, a rear lens unit LR having a positive refractive power is disposed closest to the image side, and an intermediate lens unit LM including two sub lens units Lis and Lc is disposed adjacent to the object side. Further, the front lens unit LF is arranged adjacent to the object side of the intermediate lens unit LM. The present invention is a single focal length optical system.

後側レンズ群ＬＲは、様々なレンズ構成を取ることが可能だが、基本的なレンズ構成として最も物体側のレンズ面が物体側に凹面を向けており、最も像側のレンズ面が像側に凸面を向けている。そして、後側レンズ群ＬＲは全体として正の屈折力のレンズ群となっている。後側レンズ群ＬＲの最も少ないレンズ構成としては、例えば物体側から像側へ順に、物体側に凹面を向けた負レンズ、像側に凸面を向けた正レンズであれば良い。 Rear lens group LR is it can take various lens configurations, but the basic lens surface on the most object side as the lens arrangement has a concave surface facing surfaces on the object side, a lens surface on the most image side image side The convex surface is facing. The rear lens group LR is a lens group having a positive refractive power as a whole. The smallest lens configuration of the rear lens group LR, for example, in order from the object side to the image side, a negative lens with its concave surface on the object side, may be a positive lens having a convex surface directed toward the image side.

これは例えば各実施例において負レンズと正レンズとの接合レンズを１つのレンズで構成したことに相当する。またここで述べる強い凹面とは、当該レンズ面の曲率半径の絶対値が、当該レンズ面の光線有効径に対して３倍以下の値を持つ形状であることを示している。 This corresponds to, for example, that the cemented lens of the negative lens and the positive lens is composed of one lens in each embodiment. The strong concave surface described here indicates that the absolute value of the radius of curvature of the lens surface is a shape having a value that is three times or less than the effective ray diameter of the lens surface.

後側レンズ群ＬＲのレンズ構成を前述のようなレンズ構成とすることで、特に軸上収差やコマ収差や非点収差を良好に補正することが容易となる。また、更に好ましいレンズ構成としては、物体側から像側へ順に、物体側に凹面を向けた負レンズ、正レンズ、物体側に凸面を向けた正レンズとするのが良い。このレンズ構成は全系を大口径の撮影レンズを構成するときに特に有効で、大口径の撮影光学系で発生しやすい球面収差やコマ収差、軸上色収差も良好に補正することが容易となる。 By making the lens configuration of the rear lens group LR as described above, it becomes easy to satisfactorily correct especially the axial aberration, coma aberration, and astigmatism. Still Preferred lens configuration, in order from the object side to the image side, a negative lens with its concave surface on the object side, a positive lens, is good for a positive lens having a convex surface directed toward the object side. This lens configuration is particularly effective when the entire system is configured as a large-aperture photographing lens, and it is easy to satisfactorily correct spherical aberration, coma aberration, and axial chromatic aberration that are likely to occur in a large-aperture photographing optical system. .

このような光学系において、例えばレンズ全系の内、物体側に強い負の屈折力のレンズ群を配置すると、所謂レトロフォーカスタイプの屈折力配置とすることができる。そのような光学配置とすると、像側主点を全系の最終レンズ面より像側に位置させることが容易であり、バックフォーカスより全系の焦点距離が小さい広画角レンズを実現することが容易となる。このような光学系は特に、レンズ系の像面側にクイックリターンミラーを配置する一眼レフカメラ用などバックフォーカスを長く確保し、広画角化を図る際に有用である。 In such an optical system, for example, when a lens group having a strong negative refractive power is arranged on the object side in the entire lens system, a so-called retrofocus type refractive power arrangement can be obtained. With such an optical arrangement, it is easy to position the image-side principal point on the image side from the final lens surface of the entire system, and it is possible to realize a wide-angle lens with a focal length of the entire system that is smaller than the back focus. It becomes easy. Such an optical system is particularly useful for ensuring a long back focus and widening the angle of view, such as for a single-lens reflex camera in which a quick return mirror is disposed on the image plane side of a lens system.

また、本発明の光学系において前側レンズ群ＬＦを後側レンズ群ＬＲと対称的な形状を有した正の屈折力のレンズ群として構成すると、所謂ガウスタイプ（対称型）に近い形態の光学系となる。そのような光学配置とすると、対称的な構成のレンズ群で効率的な収差補正が容易となり、全系を大口径の撮影光学系としたときでも高い光学性能を得ることが容易となる。 Further, in the optical system of the present invention, when the front lens unit LF is configured as a lens unit having a positive refractive power having a symmetrical shape with the rear lens unit LR, an optical system having a form close to a so-called Gaussian type (symmetric type). It becomes. Such an optical arrangement facilitates efficient aberration correction with a symmetrically configured lens group, and makes it easy to obtain high optical performance even when the entire system is a large-aperture imaging optical system.

本発明の光学系は、開口絞りＳＰを光学系の中央付近、即ち第１サブレンズ群Ｌｉｓを含む中間レンズ群ＬＭの中、またはその近傍に配置している。具体的には前側レンズ群ＬＦと中間レンズ群ＬＭの間、もしくは中間レンズ群ＬＭのレンズ群中、もしくは中間レンズ群ＬＭと後側レンズ群ＬＲの間に配置している。 In the optical system of the present invention, the aperture stop SP is disposed in the vicinity of the center of the optical system, that is, in the intermediate lens group LM including the first sub- lens group Lis or in the vicinity thereof. Specifically, it is arranged between the front lens group LF and the intermediate lens group LM, in the lens group of the intermediate lens group LM, or between the intermediate lens group LM and the rear lens group LR.

一般的にレンズ系において最大画角の軸外光線の光軸からの入射高さは開口絞りからの距離が離れるにつれ高くなるため、開口絞りから離れた位置のレンズは光線有効径が大きくなってくる。しかし軸外光線は開口絞り近傍では絞り中心を通過しその前後では光線の入射高が増加する。そのため軸外光線の入射高が大きくなる標準画角レンズ系から広画角レンズ系では、全系の中心近傍に開口絞りを配置することで絞り前後のレンズ径のバランスをとり、絞り近傍のレンズ径を小さくしている。 Generally, in the lens system, the incident height from the optical axis of the off-axis light beam with the maximum angle of view increases as the distance from the aperture stop increases. come. However, off-axis rays pass through the center of the aperture in the vicinity of the aperture stop, and the incident height of the light increases before and after that. For this reason, in standard to wide-angle lens systems where the incident height of off-axis rays increases, an aperture stop is placed near the center of the entire system to balance the lens diameters before and after the stop, and lenses near the stop. The diameter is reduced.

各実施例の光学系では開口絞りＳＰ近傍に第１サブレンズ群Ｌｉｓを配置することにより、第１サブレンズ群Ｌｉｓが防振のため光軸に対して垂直方向に移動してもレンズ径が大きくなるのを軽減している。また第１サブレンズ群Ｌｉｓを通る光線の入射高も小さくなり、防振時の収差変動も小さくなるようにしている。 In the optical system of each embodiment, the first sub- lens group Lis is disposed in the vicinity of the aperture stop SP, so that the lens diameter can be increased even if the first sub- lens group Lis moves in the direction perpendicular to the optical axis for vibration isolation. Reduces the growth. In addition, the incident height of the light beam passing through the first sub- lens group Lis is also reduced, and the aberration fluctuation during the image stabilization is also reduced.

各実施例の光学系では前述のように中間レンズ群ＬＭのレンズ群中や隣接する位置に開口絞りＳＰを配置することで第１サブレンズ群Ｌｉｓが開口絞りＳＰに近くなるようにして、第１サブレンズ群Ｌｉｓの有効径が大型化するのを抑制している。この結果として、第１サブレンズ群Ｌｉｓの駆動機構の負荷を少なくしつつ、レンズ全体としての小型化を図っている。 In the optical system of each example as the first sub lens group Lis is close to the aperture stop SP by placing the aperture stop SP during lens group intermediate lens group LM and adjacent positions as described above, the The effective diameter of one sub lens unit Lis is prevented from increasing. As a result, the entire lens is reduced in size while reducing the load on the drive mechanism of the first sub- lens group Lis.

また同時に、全系の中でも比較的開口絞りＳＰに近い位置のレンズ群を第１サブレンズ群Ｌｉｓとすることで、第１サブレンズ群Ｌｉｓ内を通る軸外光線の入射高を低くし、防振時の軸外光線の収差変動が少なくなるようにしている。 At the same time, by setting the lens group at a position relatively close to the aperture stop SP in the entire system as the first sub- lens group Lis, the incident height of off-axis rays passing through the first sub- lens group Lis can be reduced, thereby preventing Aberration fluctuations of off-axis rays during shaking are reduced.

中間レンズ群ＬＭは、二つの部分レンズ群により構成されている。一つは、光軸と垂直な成分を含むように移動させることで光学系が振動したときに像面上の結像位置を移動する、所謂防振を行う第１サブレンズ群Ｌｉｓである。そして他方の部分レンズ群は、第１サブレンズ群Ｌｉｓに隣接して配置し、第１サブレンズ群Ｌｉｓとは異なる符号の屈折力有し、防振時に発生する偏心収差を補正する第２サブレンズ群Ｌｃである。 The intermediate lens group LM is composed of two partial lens groups. One is a first sub- lens group Lis that performs so-called image stabilization that moves the imaging position on the image plane when the optical system vibrates by moving the optical system so as to include a component perpendicular to the optical axis. And the other partial lens group adjacent to the first sub-lens group Lis arranged, has a refractive power different sign to the first sub-lens group Lis, second sub that corrects decentration aberrations produced during image stabilization This is the lens group Lc.

このとき、第１サブレンズ群Ｌｉｓの構成レンズ枚数が多くなると、第１サブレンズ群Ｌｉｓの重量が大きくなり第１サブレンズ群Ｌｉｓを動かす駆動機構の負荷が大きくなり望ましくない。そのため、第１サブレンズ群Ｌｉｓのレンズ枚数を少なくし、隣接して防振時に発生する収差を補正する第２サブレンズ群Ｌｃを配置している。これにより防振時の収差を良好に補正した光学系を実現している。 At this time, if the number of constituent lenses of the first sub- lens group Lis increases, the weight of the first sub- lens group Lis increases and the load on the driving mechanism that moves the first sub- lens group Lis increases, which is not desirable. For this reason, the number of lenses in the first sub- lens group Lis is reduced, and a second sub- lens group Lc that corrects aberrations that occur during image stabilization is disposed adjacently. As a result, an optical system in which the aberration during the image stabilization is corrected well is realized.

具体的には、第１サブレンズ群Ｌｉｓと第２サブレンズ群Ｌｃをそれぞれ共に単レンズ又は接合レンズという一つのレンズ要素で構成し、且つ第１サブレンズ群Ｌｉｓと第２サブレンズ群Ｌｃは互いに異なる符号の屈折力を持つ構成としている。 Specifically, the first sub-lens group Lis and the second sub lens group Lc constituted by a single lens element of both single lens or a cemented lens respectively, and a first sub-lens group Lis second sub lens group Lc It has a configuration having different refractive powers.

少ないレンズで防振時にも十分な収差補正を行うためには、第１サブレンズ群Ｌｉｓで発生する収差を第２サブレンズ群Ｌｃで相殺することが肝要である。そのため第１サブレンズ群Ｌｉｓと、それに隣接する第２サブレンズ群Ｌｃを互いに異なる符号の屈折力を持つレンズ群として構成し、少ないレンズで十分な収差補正を行っている。 In order to perform sufficient aberration correction even with vibration reduction with a small number of lenses, it is important to cancel out the aberration generated in the first sub lens unit Lis by the second sub lens unit Lc. For this reason, the first sub- lens group Lis and the second sub- lens group Lc adjacent to the first sub- lens group Lis are configured as lens groups having different refractive powers, and sufficient aberration correction is performed with a small number of lenses.

また、このように第１サブレンズ群Ｌｉｓを少ないレンズで構成したことで、全系を大口径にしたときにも、第１サブレンズ群Ｌｉｓの重量が過度に大きくならず、防振駆動機構に大きな負担がかからないようにしている。またこのように隣接し合う第１サブレンズ群Ｌｉｓと第２サブレンズ群Ｌｃに互いに異なる符号の屈折力を持たせることで、第１サブレンズ群Ｌｉｓに適切な防振敏感度を持たせている。 Further, since the first sub- lens group Lis is configured with a small number of lenses as described above, the weight of the first sub- lens group Lis is not excessively increased even when the entire system has a large diameter, and the vibration-proof drive mechanism So that it does not place a heavy burden on In addition, the first sub- lens group Lis and the second sub- lens group Lc that are adjacent to each other have different refractive powers with different signs so that the first sub- lens group Lis has an appropriate vibration-proof sensitivity. Yes.

各実施例において第１サブレンズ群Ｌｉｓの焦点距離をｆｉｓ、第２サブレンズ群Ｌｃの焦点距離をｆｃとする。このとき、
０．３＜｜ｆｃ／ｆｉｓ｜＜３．５・・・（１）
なる条件式を満足している。 In each embodiment, the focal length of the first sub lens unit Lis is fis, and the focal length of the second sub lens unit Lc is fc. At this time,
0.3 <| fc / fis | <3.5 (1)
The following conditional expression is satisfied.

条件式（１）は、第１サブレンズ群Ｌｉｓと、それに隣接する第２サブレンズ群Ｌｃの屈折力のバランスを適切にし、第１サブレンズ群Ｌｉｓを光軸と垂直方向に移動させたときの収差補正分担と像位置補正の敏感度のバランスを良好に維持するためのものである。 Conditional expression (1) indicates that the balance of the refractive power of the first sub- lens group Lis and the second sub- lens group Lc adjacent thereto is made appropriate, and the first sub- lens group Lis is moved in the direction perpendicular to the optical axis. This is to maintain a good balance between the aberration correction sharing and the sensitivity of image position correction.

条件式（１）の上限を超えて第２サブレンズ群Ｌｃの屈折力に対して第１サブレンズ群Ｌｉｓの屈折力が強くなると、防振の際に偏心収差が多く発生し、光学性能が劣化してくる。また、条件式（１）の下限を超えて第１サブレンズ群Ｌｉｓの屈折力が弱くなると、防振敏感度が低くなり過ぎ、防振時に光軸と垂直成分を持つ方向に駆動させる移動量が大きくなって駆動機構が大型化してくる。また、更に好ましくは条件式（１）の数値範囲を次の如く設定するのが良い。 If the refractive power of the first sub- lens group Lis becomes stronger than the refractive power of the second sub- lens group Lc beyond the upper limit of the conditional expression (1), a large amount of decentration aberrations occur during image stabilization and the optical performance is reduced. It will deteriorate. Further, if the refractive power of the first sub lens unit Lis becomes weaker beyond the lower limit of the conditional expression (1), the vibration proof sensitivity becomes too low, and the amount of movement to be driven in a direction having a component perpendicular to the optical axis at the time of vibration proof. Becomes larger and the drive mechanism becomes larger. More preferably, the numerical range of conditional expression (1) is set as follows.

０．４＜ｆｃ／｜ｆｉｓ｜＜３．２・・・（１ａ）
各実施例によれば、以上のようにレンズ構成を規定することよって、全系を大口径のレンズとした時も、高い光学性能を持ち、防振時の収差補正も良好に行ない、且つ第１サブレンズ群Ｌｉｓの小型化を達成した光学系を得ている。 0.4 <fc / | fis | <3.2 (1a)
According to the embodiments, I'll defining a lens configuration as described above, even when the entire system as a large diameter of the lens has high optical performance, the aberration correcting also satisfactorily performed upon vibration reduction and the An optical system that achieves miniaturization of one sub lens unit Lis is obtained.

各実施例において更に好ましくは次の諸条件のうちの１以上を満足するのが良い。全系の焦点距離をｆとする。第１サブレンズ群Ｌｉｓを構成するレンズのうち、第１サブレンズ群Ｌｉｓと同符号の屈折力を有し且つ最も屈折力の絶対値の大きいレンズＧｉｓ１の材料のｄ線に対するアッベ数をνｄｉｓとする。但しアッベ数νｄｉｓは第１サブレンズ群Ｌｉｓが単一レンズより構成されているときは単一レンズの材料のアッベ数とする。 In each embodiment, it is more preferable that one or more of the following conditions be satisfied. Let f be the focal length of the entire system. Of the lenses constituting the first sub-lens group Lis, and νdis the Abbe number to the d-line of the large lens Gis1 material of the absolute value of and most power has a refractive power of the first sub-lens group Lis the same sign To do. However, the Abbe number νdis is the Abbe number of the material of the single lens when the first sub lens unit Lis is composed of a single lens.

無限遠物体にフォーカスした状態での第１サブレンズ群Ｌｉｓの横倍率をβｉｓ、後側レンズ群ＬＲの横倍率をβｒとする。第１サブレンズ群Ｌｉｓの最も物体側のレンズ面の曲率半径をｒａ、最も像側のレンズ面の曲率半径をｒｂとする。中間レンズ群ＬＭの焦点距離をｆｍとする。 Let βis be the lateral magnification of the first sub- lens group Lis while focusing on an object at infinity, and βr be the lateral magnification of the rear lens group LR. The radius of curvature of the lens surface closest to the object side in the first sub lens unit Lis is denoted by ra, and the radius of curvature of the lens surface closest to the image side is denoted by rb. Let fm be the focal length of the intermediate lens group LM.

第１サブレンズ群Ｌｉｓの最も物体側のレンズ面から最も像側のレンズ面までの光軸上の距離をＴｉｓとする。中間レンズ群ＬＭの最も物体側のレンズ面から最も像側のレンズ面までの光軸上の距離をＴｍ、全系の最も物体側のレンズ面から最も像側のレンズ面までの光軸上の距離をＴＤＬとする。第１サブレンズ群Ｌｉｓと第２サブレンズ群Ｌｃの間の光軸方向の空気間隔をＤｉｓｃとする。中間レンズ群ＬＭと後側レンズ群ＬＲの光軸方向の空気間隔をＤｍｒとする。 The distance on the optical axis from the lens surface closest to the object side to the lens surface closest to the image side of the first sub lens unit Lis is defined as Tis. The distance on the optical axis from the lens surface closest to the object side to the lens surface closest to the image side of the intermediate lens group LM is Tm, and on the optical axis from the lens surface closest to the object side to the lens surface closest to the image side in the entire system. Let the distance be TDL. The air space in the optical axis direction between the first sub lens unit Lis and the second sub lens unit Lc is defined as Disc. An air space in the optical axis direction between the intermediate lens group LM and the rear lens group LR is Dmr.

中間レンズ群ＬＭの中、もしくは物体側、もしくは像側に開口絞りＳＰを有し、第１サブレンズ群Ｌｉｓのレンズ面のうち、開口絞りＳＰに最も近いレンズ面から開口絞りＳＰまでの光軸上の距離をＤｓとする。但し以上の間隔又は距離に関するパラメータの符号は物体側から像側へ測ったときを正、その逆を負とする。このとき次の諸条件のうち１以上を満足するのが良い。 An optical axis from the lens surface closest to the aperture stop SP to the aperture stop SP among the lens surfaces of the first sub- lens group Lis in the intermediate lens group LM or on the object side or the image side. Let Ds be the upper distance. However, the sign of the parameter relating to the above interval or distance is positive when measured from the object side to the image side, and vice versa. At this time, it is preferable to satisfy one or more of the following conditions.

０．３＜｜ｆｉｓ／ｆ｜＜３．５・・・（２）
３５＜νｄｉｓ・・・（３）
０．２＜｜（１−βｉｓ）・βｒ｜＜２．０・・・（４）
−７．０＜（ｒａ＋ｒｂ）／（ｒａ−ｒｂ）＜７．０・・・（５）
０．５＜｜ｆｍ／ｆ｜・・・（６）
０．０３＜Ｔｉｓ／Ｔｍ＜０．８０・・・（７）
０．０５＜Ｔｍ／ＴＤＬ＜０．５０・・・（８）
０．３＜｜Ｄｉｓｃ／Ｔｉｓ｜＜５．０・・・（９）
０．８＜｜Ｄｍｒ／Ｄｉｓｃ｜＜６．０・・・（１０）
０．０８＜｜Ｄｓ／Ｔｍ｜＜２．００・・・（１１）
次に前述の各条件式の技術的意味について説明する。 0.3 <| fis / f | <3.5 (2)
35 <νdis (3)
0.2 <| (1-βis) · βr | <2.0 (4)
−7.0 <(ra + rb) / (ra−rb) <7.0 (5)
0.5 <| fm / f | (6)
0.03 <Tis / Tm <0.80 (7)
0.05 <Tm / TDL <0.50 (8)
0.3 <| Disc / Tis | <5.0 (9)
0.8 <| Dmr / Disc | <6.0 (10)
0.08 <| Ds / Tm | <2.00 (11)
Next, the technical meaning of each conditional expression described above will be described.

条件式（２）は、全系の焦点距離に対する第１サブレンズ群Ｌｉｓの屈折力を適切にし、第１サブレンズ群Ｌｉｓを光軸と垂直方向に移動させたときの収差変動の敏感度と像位置補正の敏感度のバランスを良好に維持するためのものである。条件式（２）の上限を超えて第１サブレンズ群Ｌｉｓの屈折力が弱くなると、防振時に光軸と垂直成分を持つ方向に移動させる量が大きくなって駆動機構が大型化してくる。条件式（２）の下限を超えて第１サブレンズ群Ｌｉｓの屈折力が強くなると、防振の際に偏心収差が多く発生し、防振時の光学性能が悪化してくる。また、更に好ましくは条件式（２）の数値範囲を次の如く設定するのが良い。 Conditional expression (2) shows the sensitivity of aberration variation when the refractive power of the first sub- lens group Lis is appropriate with respect to the focal length of the entire system and the first sub- lens group Lis is moved in the direction perpendicular to the optical axis. This is to maintain a good balance of sensitivity for image position correction. When the upper limit of conditional expression (2) is exceeded and the refractive power of the first sub lens unit Lis becomes weaker, the amount of movement in the direction having the vertical component with respect to the optical axis during vibration isolation increases, and the drive mechanism becomes larger. If the refractive power of the first sub lens unit Lis is increased beyond the lower limit of the conditional expression (2), a large amount of decentration aberration occurs during image stabilization, and the optical performance during image stabilization deteriorates. More preferably, the numerical range of conditional expression (2) is set as follows.

０．５＜｜ｆｉｓ／ｆ｜＜３．０・・・（２ａ）
条件式（３）は、第１サブレンズ群Ｌｉｓを構成するレンズのうち主たる屈折力を担うレンズの材料の特性を規定するもので、防振時に発生する収差のうち特に軸上色収差や倍率色収差などの色収差を良好に補正するためのものである。 0.5 <| fis / f | <3.0 (2a)
Conditional expression (3) prescribes the characteristics of the lens material that bears the main refractive power among the lenses constituting the first sub- lens group Lis. Among aberrations that occur during image stabilization, in particular axial chromatic aberration and lateral chromatic aberration. This is to correct chromatic aberrations such as the above.

第１サブレンズ群Ｌｉｓは小型化のためレンズ枚数は可能な限り少ないことが望ましい。最も好ましくは１つの正レンズと１つの負レンズで構成、もしくは単レンズで構成するのが良い。そのため、第１サブレンズ群Ｌｉｓを構成するレンズの内、第１サブレンズ群Ｌｉｓと同符号の屈折力を持ち且つその屈折力が最も大きいＧｉｓ１レンズが、第１サブレンズ群Ｌｉｓ全体の屈折力の大部分を担う役割を持つことになる。但し、第１サブレンズ群Ｌｉｓが単一レンズのときは、この単一レンズがレンズＧｉｓ１となる。 The first sub lens unit Lis is desirably as small as possible in order to reduce the size. Most preferably, it is composed of one positive lens and one negative lens, or a single lens. Therefore, among the lenses constituting the first sub-lens group Lis, and its power has refracting power of the first sub-lens group Lis the same sign largest Gis1 lens, the refractive power of the entire first sub-lens group Lis It will have a role to play the most part. However, when the first sub- lens group Lis is a single lens, this single lens is the lens Gis1.

条件式（３）の下限を超えてレンズＧｉｓ１を構成する材料のアッベ数が小さいと、防振時に発生する軸上色収差や倍率色収差などの色収差が大きくなり、これらの補正が困難となる。また、更に好ましくは条件式（３）の数値範囲を次の如く設定するのが良い。 If the Abbe number of the material composing the lens Gis1 is small beyond the lower limit of the conditional expression (3), chromatic aberrations such as axial chromatic aberration and lateral chromatic aberration that occur at the time of image stabilization increase, and it becomes difficult to correct these. More preferably, the numerical range of conditional expression (3) is set as follows.

４０＜νｄｉｓ・・・（３ａ）
条件式（４）は、第１サブレンズ群Ｌｉｓの光軸と垂直方向の成分の移動量と、これに伴い発生する結像面上の像点移動量の比を表し、防振効果の度合いを適切にするためのものである。条件式（４）の値は防振敏感度に相当する。 40 <νdis (3a)
Conditional expression (4) expresses the ratio of the amount of movement of the component in the direction perpendicular to the optical axis of the first sub- lens group Lis and the amount of movement of the image point on the image plane that occurs along with this, and the degree of the anti-vibration effect It is for making it appropriate. The value of conditional expression (4) corresponds to the image stabilization sensitivity.

条件式（４）の上限を超えて防振敏感度が高すぎると一定の防振効果を得るときの第１サブレンズ群Ｌｉｓの変位量（移動量）が小さくなり過ぎて、その移動量を電気的又は機械的に精度良く駆動させるのが困難になってくる。また、条件式（４）の下限値を超えて防振敏感度が低すぎる場合、防振時の光軸と垂直方向の成分の移動量が大きくなって駆動機構の負荷が大きくなってくる。また、更に好ましくは条件式（５）の数値範囲を次の如く設定するのが良い。 If the upper limit of conditional expression (4) is exceeded and the anti-vibration sensitivity is too high, the displacement amount (movement amount) of the first sub- lens group Lis when obtaining a certain anti-vibration effect becomes too small, and the movement amount is set as follows. It becomes difficult to drive it electrically or mechanically with high accuracy. Further, when the vibration proof sensitivity is too low exceeding the lower limit value of the conditional expression (4), the movement amount of the component in the direction perpendicular to the optical axis at the time of vibration proof becomes large, and the load on the drive mechanism becomes large. More preferably, the numerical range of conditional expression (5) should be set as follows.

０．３＜｜（１−βｉｓ）・βｒ｜＜１．８・・・（４ａ）
条件式（５）は、第１サブレンズ群Ｌｉｓの最も物体側（入射側）と最も像側（射出側）のレンズ面の形状を規定するもので、第１サブレンズ群Ｌｉｓをできるだけ少ないレンズで構成した上で、防振時の光学性能を良好に保つためのものである。尚、曲率半径の値の符号には、物体側に向かって凸の形状の場合は正、像側に向かって凸の形状の場合には負である。 0.3 <| (1-βis) · βr | <1.8 (4a)
Condition (5) defines the lens surface shape of the most object side (incident side) and the most image side of the first sub-lens group Lis (exit side), as few lenses of the first sub-lens group Lis In order to maintain good optical performance during image stabilization. The sign of the value of the radius of curvature is positive in the case of a convex shape toward the object side and negative in the case of a convex shape toward the image side.

条件式（５）の値が上限を超えるときは、第１サブレンズ群Ｌｉｓの最も物体側のレンズ面と最も像側のレンズ面だけの関係を見ると、曲率半径の値の差が小さい負のメニスカス形状となる。このように第１サブレンズ群Ｌｉｓへの入射面と第１サブレンズ群Ｌｉｓからの射出面がほぼ同じ形状（曲率半径）であると、一方のレンズ面で発生する収差を他方のレンズ面で補正することが難しく、少ないレンズ枚数で防振時の光学性能を良好に保つことが難しくなる。 When the value of the conditional expression (5) exceeds the upper limit, when the relationship between the lens surface closest to the object side and the lens surface closest to the image side in the first sub- lens group Lis is viewed, the difference between the values of the curvature radii is small and negative. It becomes a meniscus shape. In this way, when the entrance surface to the first sub- lens group Lis and the exit surface from the first sub- lens group Lis have substantially the same shape (curvature radius), the aberration generated on one lens surface is caused on the other lens surface. It is difficult to correct, and it becomes difficult to maintain good optical performance during image stabilization with a small number of lenses.

また条件式（５）の値が下限を超えるときは、第１サブレンズ群Ｌｉｓの最も物体側のレンズ面と最も像側のレンズ面だけの関係を見ると、曲率半径の値の差が小さい正のメニスカス形状となる。このように第１サブレンズ群Ｌｉｓへの入射面と第１サブレンズ群Ｌｉｓからの射出面がほぼ同じ形状（曲率半径）であると、一方のレンズ面で発生する収差を他方のレンズ面で補正することが難しく、少ないレンズで防振時の光学性能を良好に保つことが難しくなる。 When the value of the conditional expression (5) exceeds the lower limit, the difference in the radius of curvature is small when the relationship between the lens surface closest to the object side and the lens surface closest to the image side in the first sub lens unit Lis is viewed. Positive meniscus shape. In this way, when the entrance surface to the first sub- lens group Lis and the exit surface from the first sub- lens group Lis have substantially the same shape (curvature radius), the aberration generated on one lens surface is caused on the other lens surface. It is difficult to correct, and it becomes difficult to maintain good optical performance during image stabilization with a small number of lenses.

本発明の光学系では第１サブレンズ群Ｌｉｓをできるだけ少ないレンズで構成することが好ましいが、一方で適切な防振敏感度を得るために、十分な屈折力を持たせることも必要である。そのため、第１サブレンズ群Ｌｉｓの最も物体側（入射側）のレンズ面と最も像側（射出側）のレンズ面の曲率半径の値が、第１サブレンズ群Ｌｉｓの屈折力を適切な量にする関係であることが望ましく、そのためにも条件式（５）を満足することが望ましい。また、更に好ましくは条件式（５）の数値範囲を次の如く設定するのが良い。 In the optical system of the present invention, it is preferable that the first sub- lens group Lis is composed of as few lenses as possible. On the other hand, in order to obtain an appropriate anti-vibration sensitivity, it is necessary to have sufficient refractive power. Therefore, the value of the radius of curvature of the lens surface closest to the object side (incident side) and the lens surface closest to the image side (exit side) of the first sub lens unit Lis is an appropriate amount of the refractive power of the first sub lens unit Lis. Therefore, it is desirable to satisfy the conditional expression (5). More preferably, the numerical range of conditional expression (5) should be set as follows.

−５．０＜（ｒａ＋ｒｂ）／（ｒａ−ｒｂ）＜５．０・・・（５ａ）
条件式（６）は、中間レンズ群ＬＭ全体の焦点距離と全系の焦点距離の比率を規定するもので、全系における光学性能を良好に保つためのものである。 -5.0 <(ra + rb) / (ra-rb) <5.0 (5a)
Conditional expression (6) defines the ratio between the focal length of the entire intermediate lens group LM and the focal length of the entire system, and is intended to maintain good optical performance in the entire system.

本発明の光学系において、第１サブレンズ群Ｌｉｓと第２サブレンズ群Ｌｃから構成される中間レンズ群ＬＭは、防振機能の追加と防振時の収差補正を行うための構成であることが望ましい。しかしその一方で、中間レンズ群ＬＭは防振を行わない平常撮影時においてもレンズ群内で十分な収差補正を行い、前側レンズ群ＬＦや後側レンズ群ＬＲに収差補正の負担を掛けないことが望ましい。即ち、中間レンズ群ＬＭ自体としては、なるべく屈折力が弱く、アフォーカルな系であることが望ましい。 In the optical system of the present invention, the intermediate lens group LM composed of the first sub- lens group Lis and the second sub- lens group Lc is configured to add an anti-vibration function and correct aberrations at the time of anti-vibration. Is desirable. However, on the other hand, the intermediate lens unit LM performs sufficient aberration correction in the lens unit even during normal shooting without image stabilization, and does not place an aberration correction burden on the front lens unit LF and the rear lens unit LR. Is desirable. That is, it is desirable that the intermediate lens group LM itself be an afocal system with a refractive power as weak as possible.

条件式（６）の範囲を超えて中間レンズ群ＬＭの屈折力が強くなると、中間レンズ群ＬＭで発生する諸収差を前側レンズ群ＬＦや後側レンズ群ＬＲで補正する負担が大きくなるため望ましくない。また、更に好ましくは条件式（６）の数値範囲を次の如く設定するのが良い。 If the refractive power of the intermediate lens group LM is increased beyond the range of the conditional expression (6), it is desirable because the burden of correcting various aberrations generated in the intermediate lens group LM by the front lens group LF and the rear lens group LR is increased. Absent. More preferably, the numerical range of conditional expression (6) is set as follows.

０．７＜｜ｆｍ／ｆ｜・・・（６ａ）
条件式（７）は、中間レンズ群ＬＭ内における第１サブレンズ群Ｌｉｓの光軸上の厚みの比率を規定するもので、十分な防振時の光学性能を保ちつつ、第１サブレンズ群Ｌｉｓ及びレンズ全系の大型化を抑制ためのものである。条件式（７）の上限を超えて第１サブレンズ群Ｌｉｓの光軸上の厚みが大きいと、第１サブレンズ群Ｌｉｓが大型化して防振のための駆動機構の負荷が大きくなってくる。また条件式（７）の下限を超えて第１サブレンズ群Ｌｉｓの光軸上の厚みが小さいと、防振時にも良好な光学性能を達成するためのレンズ構成とすることが難しく望ましくない。また、更に好ましくは条件式（７）の数値範囲を次の如く設定するのが良い。 0.7 <| fm / f | (6a)
Condition (7) defines the ratio of the thickness on the optical axis of the first sub-lens group Lis in the intermediate lens group LM, while maintaining the optical performance at the time sufficient image stabilization, the first sub-lens group This is for suppressing the enlargement of Lis and the entire lens system. If the upper limit of conditional expression (7) is exceeded and the thickness of the first sub- lens group Lis on the optical axis is large, the first sub- lens group Lis becomes large and the load on the drive mechanism for vibration isolation becomes large. . Further, if the thickness on the optical axis of the first sub lens unit Lis is small beyond the lower limit of the conditional expression (7), it is difficult and undesirable to obtain a lens configuration for achieving good optical performance even during image stabilization. More preferably, the numerical range of conditional expression (7) should be set as follows.

０．０５＜Ｔｉｓ／Ｔｍ＜０．７０・・・（７ａ）
条件式（８）は、全系における中間レンズ群ＬＭの光軸上の厚みの比率を規定するもので、十分な光学性能を保ちつつ、レンズ全系の大型化を抑制するためのものである。条件式（８）の上限を超えて中間レンズ群ＬＭの光軸上の厚みが大きいと、全系が大型化するので望ましくない。また条件式（８）の下限を超えて中間レンズ群ＬＭの光軸上の厚みが小さいと、十分な収差補正を行った上で第１サブレンズ群Ｌｉｓを付加することが困難となる。また、更に好ましくは条件式（８）の数値範囲を次の如く設定するのが良い。 0.05 <Tis / Tm <0.70 (7a)
Conditional expression (8) defines the ratio of the thickness on the optical axis of the intermediate lens group LM in the entire system, and is intended to suppress the enlargement of the entire lens system while maintaining sufficient optical performance. . If the upper limit of conditional expression (8) is exceeded and the thickness of the intermediate lens group LM on the optical axis is large, the entire system becomes large, which is not desirable. If the thickness on the optical axis of the intermediate lens group LM is small beyond the lower limit of the conditional expression (8), it is difficult to add the first sub lens group Lis after sufficient aberration correction. More preferably, the numerical range of conditional expression (8) is set as follows.

０．０８＜Ｔｍ／ＴＤＬ＜０．４０・・・（８ａ）
条件式（９）は、第１サブレンズ群Ｌｉｓと第２サブレンズ群Ｌｃの光軸上の空気間隔を適正に規定し、レンズ全系の大型化を抑制しながらも必要なメカ機構を配置し、その上で防振時の収差補正を良好に行うためのものである。条件式（９）の上限を超えて第１サブレンズ群Ｌｉｓと第２サブレンズ群Ｌｃの空気間隔が大きいと、第１サブレンズ群Ｌｉｓで発生する収差を第２サブレンズ群Ｌｃで補正することが困難となる。 0.08 <Tm / TDL <0.40 (8a)
Conditional expression (9) properly defines the air spacing on the optical axis of the first sub- lens group Lis and the second sub- lens group Lc, and arranges necessary mechanical mechanisms while suppressing the enlargement of the entire lens system. On top of that, the aberration correction at the time of image stabilization is performed satisfactorily. If the air space between the first sub- lens group Lis and the second sub- lens group Lc exceeds the upper limit of the conditional expression (9), the aberration generated in the first sub- lens group Lis is corrected by the second sub- lens group Lc. It becomes difficult.

また同時に、全系の中央付近に位置する中間レンズ群ＬＭ内に大きな空気間隔を作ることで、全系の最も物体側の第１レンズや最終レンズの有効径が大きくなり、レンズ全系が大型化してしまう。条件式（９）の下限を超えて第１サブレンズ群Ｌｉｓと第２サブレンズ群Ｌｃの空気間隔が小さいと、第１サブレンズ群Ｌｉｓの駆動機構や第２サブレンズ群Ｌｃを保持する機構を配置することが困難となる。また、更に好ましくは条件式（９）の数値範囲を次の如く設定するのが良い。 At the same time, by creating a large air gap in the intermediate lens group LM located near the center of the entire system, the effective diameter of the first lens and the final lens on the most object side of the entire system is increased, and the entire lens system is large. It will become. When the air space between the first sub lens group Lis and the second sub lens group Lc is small beyond the lower limit of the conditional expression (9), the driving mechanism of the first sub lens group Lis and the mechanism for holding the second sub lens group Lc It becomes difficult to arrange. More preferably, the numerical range of conditional expression (9) is set as follows.

０．４＜｜Ｄｉｓｃ／Ｔｉｓ｜＜４．６・・・（９ａ）
条件式（１０）は、中間レンズ群ＬＭと後側レンズ群ＬＲの空気間隔の比率を適切に規定し、全系の大型化を抑制しながらも必要なメカ機構を配置し、その上で良好な光学性能を満足するためのものである。条件式（１０）の上限を超えて中間レンズ群ＬＭと後側レンズ群ＬＲの空気間隔が大きいと、後側レンズ群ＬＲに入射する軸外光束の入射高さが高くなり、後側レンズ群ＬＲが大型化する。また同時に後側レンズ群ＬＲで発生する軸外収差も大きくなり、この収差の補正が困難となる。 0.4 <| Disc / Tis | <4.6 (9a)
Conditional expression (10) properly defines the ratio of the air gap between the intermediate lens group LM and the rear lens group LR, and arranges necessary mechanical mechanisms while suppressing the enlargement of the entire system, and is good on that This is for satisfying the desired optical performance. If the upper limit of conditional expression (10) is exceeded and the air space between the intermediate lens group LM and the rear lens group LR is large, the incident height of the off-axis light beam incident on the rear lens group LR increases, and the rear lens group. LR increases in size. At the same time, off-axis aberrations generated in the rear lens group LR also increase, making it difficult to correct this aberration.

条件式（１０）の下限を超えて中間レンズ群ＬＭと後側レンズ群ＬＲの空気間隔が小さいと、第１サブレンズ群Ｌｉｓの駆動機構や後側レンズ群ＬＲを保持する機構を配置することが困難となる。また、更に好ましくは条件式（１０）の数値範囲を次の如く設定するのが良い。 If the air space between the intermediate lens group LM and the rear lens group LR is small beyond the lower limit of the conditional expression (10), a driving mechanism for the first sub lens group Lis and a mechanism for holding the rear lens group LR are arranged. It becomes difficult. More preferably, the numerical range of conditional expression (10) is set as follows.

１．０＜｜Ｄｍｒ／Ｄｉｓｃ｜＜５．０・・・（１０ａ）
条件式（１１）は、第１サブレンズ群Ｌｉｓから開口絞りＳＰまでの光軸上の距離を適切に規定し、第１サブレンズ群Ｌｉｓの大型化を抑制し、且つ防振時の収差を良好に保つためのものである。条件式（１１）の上限を超えて第１サブレンズ群Ｌｉｓから開口絞りＳＰまでの距離が大きいと、第１サブレンズ群Ｌｉｓの口径が大きくなり、第１サブレンズ群Ｌｉｓの保持機構の大型化や駆動機構の負荷が増大してくる。 1.0 <| Dmr / Disc | <5.0 (10a)
Conditional expression (11) appropriately defines the distance on the optical axis from the first sub- lens group Lis to the aperture stop SP, suppresses an increase in the size of the first sub- lens group Lis, and reduces aberrations during image stabilization. It is for keeping good. If the distance from the first sub lens unit Lis to the aperture stop SP is larger than the upper limit of the conditional expression (11), the aperture of the first sub lens unit Lis increases, and the holding mechanism of the first sub lens unit Lis is large. And the load on the drive mechanism increases.

また同時に、第１サブレンズ群Ｌｉｓ内を通過する軸外光線の入射高さが高くなるため、防振時の収差補正が難しくなる。条件式（１１）の下限を超えて第１サブレンズ群Ｌｉｓから開口絞りＳＰまでの距離が小さいと、第１サブレンズ群Ｌｉｓの駆動機構と開口絞りＳＰの駆動機構を配置することが困難となる。また、更に好ましくは条件式（１１）の数値範囲を次の如く設定するのが良い。 At the same time, the incident height of off-axis rays passing through the first sub- lens group Lis is increased, so that it is difficult to correct aberrations during image stabilization. If the distance from the first sub lens unit Lis to the aperture stop SP is small beyond the lower limit of the conditional expression (11), it is difficult to arrange the drive mechanism of the first sub lens unit Lis and the drive mechanism of the aperture stop SP. Become. More preferably, the numerical range of conditional expression (11) is set as follows.

０．１＜｜Ｄｓ／Ｔｍ｜＜１．５・・・（１１ａ）
各実施例において、後側レンズ群ＬＲは、物体側から像側へ順に物体側の面が凹形状の負レンズ、像側の面が凸形状の正レンズ、像側の面が凸形状の正レンズより構成するのが良い。本発明の光学系において後側レンズ群ＬＲは光軸からレンズ周辺に向かうに従って正の屈折力が弱まる形状の非球面を有しているのが好ましい。 0.1 <| Ds / Tm | <1.5 (11a)
In each embodiment, the rear lens unit LR includes, in order from the object side to the image side, a negative lens having a concave surface on the object side, a positive lens having a convex surface on the image side, and a positive lens having a convex surface on the image side. It is better to use a lens. In the optical system of the present invention, it is preferable that the rear lens unit LR has an aspherical surface in which the positive refractive power decreases from the optical axis toward the lens periphery.

各実施例において、前側レンズ群ＬＦは物体側から像側へ順に、物体側の面が凸形状の２つの正レンズ、像側の面が凹形状の負レンズ、又は物体側の面が凸形状の２つの正レンズ、像側の面が凹形状の負レンズ、正レンズより構成するのが良い。又は前側レンズ群ＬＦは物体側から像側へ順に、物体側の面が凸でメニスカス形状の負レンズ、正レンズと負レンズとを接合した接合レンズより構成するのが良い。 In each embodiment, the front lens unit LF includes, in order from the object side to the image side, two positive lenses having a convex surface on the object side, a negative lens having a concave surface on the image side, or a convex surface on the object side. These two positive lenses, a negative lens having a concave surface on the image side, and a positive lens are preferably used. Alternatively, the front lens unit LF may be composed of a meniscus negative lens having a convex surface on the object side and a cemented lens in which a positive lens and a negative lens are cemented in order from the object side to the image side.

又は前側レンズ群ＬＦは物体側から像側へ順に、物体側の面が凸でメニスカス形状の負レンズ、物体側のレンズ面が凸形状の正レンズより構成される第ａサブレンズ群を有するのが良い。更に物体側の面が凸でメニスカス形状の負レンズ、正レンズと負レンズとを接合した接合レンズより構成される第ｂサブレンズ群を有するのが良い。 Alternatively, the front lens group LF includes, in order from the object side to the image side, an a-th sub- lens group including a negative lens having a convex meniscus shape on the object side and a positive lens having a convex lens surface on the object side. Is good. Further, it is preferable to have a b-th sub- lens group constituted by a meniscus negative lens having a convex object side surface and a cemented lens in which a positive lens and a negative lens are cemented.

以上のように各実施例によれば、防振時に発生する諸収差が良好に補正された光学系が得られる。また同時に、防振レンズを駆動する機構に過大な負荷が生じない簡易なレンズ構成で、全系としてもコンパクトな光学系が得られる。次に各実施例のレンズ構成について説明する。 As described above, according to each embodiment, it is possible to obtain an optical system in which various aberrations that occur during image stabilization are well corrected. At the same time, it is possible to obtain a compact optical system as a whole system with a simple lens configuration in which an excessive load is not generated in the mechanism for driving the image stabilizing lens. Next, the lens configuration of each example will be described.

［実施例１］
実施例１の光学系は、所謂、標準域の焦点距離を持つガウスタイプのレンズ構成を発展させたものである。最も像側に、物体側から像側へ順に、物体側に凹面を向けた負レンズと、正レンズとを接合した接合レンズ、像側に凸面を向けた正レンズで構成された後側レンズ群ＬＲを配置している。そして正レンズで構成された第１サブレンズ群Ｌｉｓと、負レンズで構成された第２サブレンズ群Ｌｃから成る中間レンズ群ＬＭを後側レンズ群ＬＲの物体側に隣接して配置している。 [Example 1]
The optical system of Example 1 is a development of a so-called Gaussian lens configuration having a standard focal length. Rear lens group consisting of a negative lens with a concave surface facing the object side, a cemented lens with a positive lens cemented, and a positive lens with a convex surface facing the image side, in order from the object side to the image side LR is arranged. An intermediate lens unit LM including a first sub lens unit Lis composed of a positive lens and a second sub lens unit Lc composed of a negative lens is disposed adjacent to the object side of the rear lens unit LR. .

そして物体側から像側へ順に物体側の面が凸形状の２つの正レンズ、像側の面が凹形状の負レンズで構成された前側レンズ群ＬＦを中間レンズ群ＬＭの物体側に隣接して配置している。開口絞りは中間レンズ群ＬＭと後側レンズ群ＬＲの間に配置している。 The front lens group LF composed of two positive lenses having a convex surface on the object side and a negative lens having a concave surface on the image side is adjacent to the object side of the intermediate lens group LM in order from the object side to the image side. Arranged. The aperture stop is disposed between the intermediate lens group LM and the rear lens group LR.

防振は、正レンズで構成された第１サブレンズ群Ｌｉｓを光軸に対して垂直方向の成分を持つ方向に移動させて行っている。また、無限遠物体から近距離物体へのフォーカシングは光学系全体を物体側に移動させて行っている。各収差図から明らかなように本実施例では基準状態及び防振時も含めて諸収差が良好に補正されている。 Anti-vibration is performed by moving the first sub- lens group Lis composed of a positive lens in a direction having a component perpendicular to the optical axis. Further, focusing from an infinitely distant object to a close object is performed by moving the entire optical system to the object side. As is apparent from the respective aberration diagrams, in this embodiment, various aberrations are corrected well including the reference state and the image stabilization.

［実施例２］
実施例２の光学系は、実施例１と同様に所謂、標準域の焦点距離を持つガウスタイプのレンズ構成を発展させたものである。最も像側に、物体側から像側へ順に、物体側に凹面を向けた負レンズと正レンズとを接合した接合レンズ、像側に凸面を向けた正レンズで構成された後側レンズ群ＬＲを配置している。そして物体側から像側へ順に、負レンズで構成された第２サブレンズ群Ｌｃと、正レンズで構成された第１サブレンズ群Ｌｉｓとから成る中間レンズ群ＬＭを後側レンズ群ＬＲの物体側に隣接して配置している。 [Example 2]
The optical system according to the second embodiment is a development of a so-called Gauss type lens configuration having a focal length in a standard range as in the first embodiment. Rear lens group LR composed of a cemented lens in which a negative lens having a concave surface facing the object side and a positive lens are cemented in order from the object side to the image side, and a positive lens having a convex surface directed to the image side. Is arranged. Then, in order from the object side to the image side, an intermediate lens group LM composed of a second sub lens group Lc composed of a negative lens and a first sub lens group Lis composed of a positive lens is replaced with an object of the rear lens group LR. Adjacent to the side.

そして物体側から像側へ順に、物体側の面が凸形状の２つの正レンズ、像側の面が凹形状の負レンズ、正レンズで構成された前側レンズ群ＬＦを中間レンズ群ＬＭの物体側に隣接して配置している。開口絞りＳＰは中間レンズ群ＬＭと後側レンズ群ＬＲの間に配置している。 Then, in order from the object side to the image side, the front lens group LF composed of two positive lenses having a convex surface on the object side, a negative lens having a concave surface on the image side, and a positive lens is used as an object of the intermediate lens group LM. Adjacent to the side. The aperture stop SP is disposed between the intermediate lens group LM and the rear lens group LR.

［実施例３］
実施例３の光学系は、実施例１と同様に所謂、標準域の焦点距離を持つガウスタイプのレンズ構成を発展させたものである。最も像側に、物体側から像側へ順に、物体側に凹面を向けた負レンズと正レンズとを接合した接合レンズ、像側に凸面を向けた正レンズで構成された後側レンズ群ＬＲを配置している。そして物体側から像側へ順に、負レンズで構成された第１サブレンズ群Ｌｉｓと、正レンズで構成された第２サブレンズ群Ｌｃとから成る中間レンズ群ＬＭを後側レンズ群ＬＲの物体側に隣接して配置している。 [Example 3]
The optical system of the third embodiment is a development of a so-called Gaussian lens configuration having a standard focal length, as in the first embodiment. Rear lens group LR composed of a cemented lens in which a negative lens having a concave surface facing the object side and a positive lens are cemented in order from the object side to the image side, and a positive lens having a convex surface directed to the image side. Is arranged. Then, in order from the object side to the image side, an intermediate lens group LM including a first sub- lens group Lis composed of a negative lens and a second sub- lens group Lc composed of a positive lens is replaced with an object of the rear lens group LR. Adjacent to the side.

防振は、負レンズで構成された第１サブレンズ群Ｌｉｓを光軸に対して垂直方向の成分を持つ方向に移動させて行っている。また、無限遠物体から近距離物体へのフォーカシングは光学系全体を物体側に移動させて行っている。各収差図から明らかなように本実施例では基準状態及び防振時も含めて諸収差が良好に補正されている。 The image stabilization is performed by moving the first sub- lens group Lis composed of a negative lens in a direction having a component perpendicular to the optical axis. Further, focusing from an infinitely distant object to a close object is performed by moving the entire optical system to the object side. As is apparent from the respective aberration diagrams, in this embodiment, various aberrations are corrected well including the reference state and the image stabilization.

［実施例４］
実施例４の光学系は、所謂、広角域の焦点距離を持つレトロフォーカスタイプのレンズ構成を発展させたものである。最も像側に、物体側から像側へ順に、物体側に凹面を向けた負レンズと正レンズとを接合した接合レンズ、像側に凸面を向けた正レンズで構成された後側レンズ群ＬＲを配置している。そして物体側から像側へ順に正レンズと負レンズが接合され全体として正の屈折力の接合レンズで構成された第２サブレンズ群Ｌｃと、負レンズで構成された第１サブレンズ群Ｌｉｓとから成る中間レンズ群ＬＭを後側レンズ群ＬＲの物体側に隣接して配置している。 [Example 4]
The optical system of Example 4 is a development of a so-called retrofocus lens configuration having a so-called wide-angle focal length. Rear lens group LR composed of a cemented lens in which a negative lens having a concave surface facing the object side and a positive lens are cemented in order from the object side to the image side, and a positive lens having a convex surface directed to the image side. Is arranged. Then, in order from the object side to the image side, a positive lens and a negative lens are cemented to form a second sub lens unit Lc composed of a cemented lens having a positive refractive power as a whole, and a first sub lens unit Lis composed of a negative lens. Is arranged adjacent to the object side of the rear lens group LR.

そして物体側から像側へ順に、物体側に凸面を向けたメニスカス形状の負レンズ、開口径不要の副絞りＳＰ２、正レンズと負レンズが接合され全体で正の屈折力の接合レンズで構成された前側レンズ群ＬＦを中間レンズ群ＬＭの物体側に隣接して配置している。開口絞りＳＰは、中間レンズ群ＬＭ内の第２サブレンズ群Ｌｃと第１サブレンズ群Ｌｉｓの間に配置している。 Then, in order from the object side to the image side, a meniscus negative lens having a convex surface facing the object side, a sub stop SP2 that does not require an aperture diameter, and a positive lens and a negative lens are cemented to form a cemented lens having a positive refractive power as a whole. The front lens unit LF is disposed adjacent to the object side of the intermediate lens unit LM. The aperture stop SP is disposed between the second sub lens group Lc and the first sub lens group Lis in the intermediate lens group LM.

［実施例５］
実施例５の光学系は、所謂、広角域の焦点距離を持つレトロフォーカスタイプのレンズ構成を発展させたものである。最も像側に、物体側から像側へ順に、物体側に凹面を向けた負レンズと、正レンズとを接合した接合レンズ、像側に凸面を向けた正レンズで構成された後側レンズ群ＬＲを配置している。そして物体側から像側へ順に、正レンズと負レンズが接合され全体として正の屈折力の接合レンズで構成された第２サブレンズ群Ｌｃと、負レンズで構成された第１サブレンズ群Ｌｉｓとから成る中間レンズ群ＬＭを後側レンズ群ＬＲの物体側に隣接して配置している。 [Example 5]
The optical system of Example 5 is a development of a so-called retrofocus lens configuration having a so-called wide-angle focal length. Rear lens group consisting of a negative lens with a concave surface facing the object side, a cemented lens with a positive lens cemented, and a positive lens with a convex surface facing the image side, in order from the object side to the image side LR is arranged. Then, in order from the object side to the image side, a positive lens and a negative lens are cemented to form a second sub lens unit Lc composed of a cemented lens having a positive refractive power as a whole, and a first sub lens unit Lis composed of a negative lens. Is arranged adjacent to the object side of the rear lens group LR.

そして中間レンズ群ＬＭの物体側に隣接して、前側レンズ群ＬＦを配置している。前側レンズ群ＬＦは、物体側に配置した第ａサブレンズ群ＬＦ１と、像側に配置した第ｂサブレンズ群ＬＦ２から構成される。第ａサブレンズ群ＬＦ１は、物体側から像側へ順に、物体側の面が凸でメニスカス形状の負レンズ、物体側の面が凸形状の正レンズで構成されている。第ｂサブレンズ群ＬＦ２は、物体側から像側へ順に、物体側の面が凸でメニスカス形状の負レンズ、正レンズと負レンズとを接合し、全体として正の屈折力の接合レンズで構成されている。 A front lens group LF is disposed adjacent to the object side of the intermediate lens group LM. The front lens group LF includes an a-th sub lens group LF1 disposed on the object side and a b-th sub lens group LF2 disposed on the image side. In order from the object side to the image side, the a-th sub lens unit LF1 includes a negative lens having a convex meniscus shape on the object side and a positive lens having a convex surface on the object side. The b-th sub lens unit LF2 is composed of a meniscus negative lens having a convex surface on the object side and a positive lens and a negative lens in order from the object side to the image side, and a cemented lens having a positive refractive power as a whole. Has been.

開口絞りＳＰは、前側レンズ群ＬＦと中間レンズ群ＬＭの間に配置している。防振は、負レンズで構成された第１サブレンズ群Ｌｉｓを光軸に対して垂直方向の成分を持つ方向に移動させて行っている。また、無限遠物体から近距離物体へのフォーカシングは、前側レンズ群ＬＦ内の第ｂサブレンズ群ＬＦ２と中間レンズ群ＬＭと後側レンズ群ＬＲを一体として物体側に移動させて行っている。この時、第ａサブレンズ群ＬＦ１は、光軸上不動である。各収差図から明らかなように本実施例では基準状態及び防振時も含めて諸収差が良好に補正されている。 The aperture stop SP is disposed between the front lens group LF and the intermediate lens group LM. The image stabilization is performed by moving the first sub- lens group Lis composed of a negative lens in a direction having a component perpendicular to the optical axis. Further, focusing from an infinite object to a close object is performed by moving the b-th sub lens group LF2, the intermediate lens group LM, and the rear lens group LR in the front lens group LF together as an object side. At this time, the a-th sub lens unit LF1 is stationary on the optical axis. As is apparent from the respective aberration diagrams, in this embodiment, various aberrations are corrected well including the reference state and the image stabilization.

以上、本発明の好ましい実施形態について説明したが、本発明はこれらの実施形態に限定されず、その要旨の範囲内で種々の変形及び変更が可能である。 As mentioned above, although preferable embodiment of this invention was described, this invention is not limited to these embodiment, A various deformation | transformation and change are possible within the range of the summary.

次に、本発明の光学系を用いた一眼レフカメラシステム（撮像装置）の実施例を、図１６を用いて説明する。 Next, an embodiment of a single-lens reflex camera system (imaging device) using the optical system of the present invention will be described with reference to FIG.

図１６において、１０は一眼レフカメラ本体、１１は本発明による光学系を搭載した交換レンズである。１２は交換レンズ１１を通して得られる被写体像を記録するフィルムや撮像素子などの記録手段である。１３は交換レンズ１１からの被写体像を観察するファインダー光学系、１４は交換レンズ１１で形成された被写体像を記録手段１２とファインダー光学系１３に切り替えて伝送するための回動するクイックリターンミラーである。 In FIG. 16, 10 is a single-lens reflex camera body, and 11 is an interchangeable lens equipped with an optical system according to the present invention. Reference numeral 12 denotes a recording unit such as a film or an image sensor for recording a subject image obtained through the interchangeable lens 11. Reference numeral 13 denotes a finder optical system for observing a subject image from the interchangeable lens 11, and reference numeral 14 denotes a rotating quick return mirror for switching the subject image formed by the interchangeable lens 11 to the recording means 12 and the finder optical system 13 for transmission. is there.

ファインダーで被写体像を観察する場合は、クイックリターンミラー１４を介してピント板１５に結像した被写体像をペンタプリズム１６で正立像としたのち、接眼光学系１７で拡大して観察する。撮影時にはクイックリターンミラー１４が矢印方向に回動して被写体像は記録手段１２に結像して記録される。１８はサブミラー、１９は焦点検出装置である。 When observing the subject image with the finder, the subject image formed on the focusing plate 15 via the quick return mirror 14 is made into an erect image with the pentaprism 16 and then magnified and observed with the eyepiece optical system 17. At the time of shooting, the quick return mirror 14 rotates in the direction of the arrow, and the subject image is formed and recorded on the recording means 12. Reference numeral 18 denotes a submirror, and 19 denotes a focus detection device.

このように本発明の光学系を一眼レフカメラ等の交換レンズ等の撮像装置に適用することにより、高い光学性能を有した撮像装置が実現できる。尚、本発明はクイックリターンミラーのないミラーレンズの一眼レフカメラにも同様に適用することができる。又、プロジェクター用の投射レンズにも同様に適用することができる。 In this way, by applying the optical system of the present invention to an imaging apparatus such as an interchangeable lens such as a single-lens reflex camera, an imaging apparatus having high optical performance can be realized. The present invention can be similarly applied to a single-lens reflex camera having a mirror lens without a quick return mirror. Further, the present invention can be similarly applied to a projection lens for a projector.

以下に、実施例１〜５に各々対応する数値実施例１〜５を示す。各数値実施例において、ｉは物体側からの面の順番を示し、ｒｉは第ｉ番目（第ｉ面）の曲率半径である。ｄｉは第ｉ面と第ｉ＋１面との間の間隔である。ｎｄｉ、νｄｉはそれぞれｄ線を基準とした屈折率、アッベ数を示す。ＢＦはバックフォーカスである。＊はその面が非球面であることを示す。（非球面データ）には、非球面を次式で表した場合の非球面係数を示す。 In the following, numerical examples 1 to 5 corresponding to the first to fifth examples will be described. In each numerical example, i indicates the order of the surfaces from the object side, and ri is the i-th (i-th surface) radius of curvature. di is an interval between the i-th surface and the i + 1-th surface. ndi and νdi denote a refractive index and an Abbe number based on the d line, respectively. BF is a back focus. * Indicates that the surface is aspherical. (Aspheric data) shows the aspheric coefficient when the aspheric surface is expressed by the following equation.

ｘ＝（ｈ²／Ｒ）／［１＋｛１−（１＋ｋ）（ｈ／Ｒ）²｝^1/2＋Ｂ・ｈ⁴＋Ｃ・ｈ⁶＋Ｄ
・ｈ⁸＋Ｅ・ｈ¹⁰＋Ｆ・ｈ¹²
但し、
ｘ：光軸方向の基準面からの変位量である。
ｈ：光軸に対して垂直な方向の高さである。
Ｒ：ベースとなる２次曲面の半径である。
Ｂ、Ｃ、Ｄ、Ｅ、Ｆはそれぞれ４次、６次、８次、１０次、１２次の非球面係数である。なお、「ｅ−Ｚ」の表示は「１０^−Ｚ」を意味する。又前述の各条件式と数値実施例における諸数値との関係を表１に示す。 x = (h ² / R) / [1+ {1− (1 + k) (h / R) ² } ^1/2 + B · h ⁴ + C · h ⁶ + D
・ H ⁸ + E ・ h ¹⁰ + F ・ h ¹²
However,
x: A displacement amount from the reference plane in the optical axis direction.
h: Height in the direction perpendicular to the optical axis.
R: radius of a quadric surface as a base.
B, C, D, E, and F are fourth-order, sixth-order, eighth-order, tenth-order, and twelfth-order aspheric coefficients, respectively. In addition, the display of “e-Z” means “10 ^−Z ”. Table 1 shows the relationship between the above-described conditional expressions and numerical values in the numerical examples.

（数値実施例１）
単位 mm

面データ
面番号 r d nd νd
1 31.773 4.30 1.80100 35.0
2 83.844 0.97
3 27.256 2.95 1.83400 37.2
4 40.105 2.38
5 80.926 1.09 1.80518 25.4
6 17.692 4.20
7 45.335 3.04 1.72916 54.7
8 -107.867 1.85
9 -92.367 0.90 1.53172 48.8
10 48.296 2.47
11(絞り) ∞ 5.25
12 -15.412 1.76 1.62588 35.7
13 -83.017 4.50 1.72916 54.7
14 -19.139 0.19
15 171.760 3.09 1.77250 49.6
16 -55.521

焦点距離 51.51
Fナンバー 1.85
半画角（度） 22.78
像高 21.64
レンズ全長 76.78
BF 37.84

第１サブレンズ群（第７面〜８面）データ
ｆｉｓ 44.15
(Numerical example 1)
Unit mm

Surface data surface number rd nd νd
1 31.773 4.30 1.80 100 35.0
2 83.844 0.97
3 27.256 2.95 1.83400 37.2
4 40.105 2.38
5 80.926 1.09 1.80518 25.4
6 17.692 4.20
7 45.335 3.04 1.72916 54.7
8 -107.867 1.85
9 -92.367 0.90 1.53172 48.8
10 48.296 2.47
11 (Aperture) ∞ 5.25
12 -15.412 1.76 1.62588 35.7
13 -83.017 4.50 1.72916 54.7
14 -19.139 0.19
15 171.760 3.09 1.77250 49.6
16 -55.521

Focal length 51.51
F number 1.85
Half angle of view (degrees) 22.78
Statue height 21.64
Total lens length 76.78
BF 37.84

First sub lens group (7th to 8th surfaces) data fis 44.15

（数値実施例２）
面データ
面番号 r d nd νd
1 37.825 4.32 1.80100 35.0
2 160.637 0.23
3 25.234 3.33 1.85026 32.3
4 46.003 1.03
5 76.174 1.10 1.78472 25.7
6 17.794 1.95
7 28.397 2.30 1.83400 37.2
8 35.816 3.44
9 8249.110 0.80 1.71736 29.5
10 28.608 2.75
11 67.699 2.51 1.73400 51.5
12 -87.694 0.90
13(絞り) ∞ 5.47
14 -15.067 1.53 1.62588 35.7
15 -83.845 4.69 1.73400 51.5
16 -19.370 0.20
17 -314.166 2.92 1.77250 49.6
18 -39.907

焦点距離 50.94
Fナンバー 1.85
半画角（度） 23.01
像高 21.64
レンズ全長 77.30
BF 37.85

第１サブレンズ群（第１１面〜１２面）データ
ｆｉｓ 52.41
(Numerical example 2)
Surface data surface number rd nd νd
1 37.825 4.32 1.80 100 35.0
2 160.637 0.23
3 25.234 3.33 1.85026 32.3
4 46.003 1.03
5 76.174 1.10 1.78472 25.7
6 17.794 1.95
7 28.397 2.30 1.83400 37.2
8 35.816 3.44
9 8249.110 0.80 1.71736 29.5
10 28.608 2.75
11 67.699 2.51 1.73400 51.5
12 -87.694 0.90
13 (Aperture) ∞ 5.47
14 -15.067 1.53 1.62588 35.7
15 -83.845 4.69 1.73400 51.5
16 -19.370 0.20
17 -314.166 2.92 1.77250 49.6
18 -39.907

Focal length 50.94
F number 1.85
Half angle of view (degrees) 23.01
Statue height 21.64
Total lens length 77.30
BF 37.85

First sub lens group (11th to 12th surfaces) data fis 52.41

（数値実施例３）
面データ
面番号 r d nd νd
1 29.364 4.85 1.80100 35.0
2 83.620 0.20
3 24.070 2.92 1.85026 32.3
4 34.438 1.71
5 54.257 1.10 1.84666 23.8
6 16.006 2.98
7 43.536 2.64 1.77250 49.6
8 -428.522 2.16
9 -103.621 0.80 1.78590 44.2
10 44.955 2.89
11 -1088.042 1.75 1.74100 52.6
12 -78.891 0.80
13(絞り) ∞ 5.39
14 -14.681 1.37 1.64769 33.8
15 -120.986 4.85 1.77250 49.6
16 -18.870 0.20
17 451.320 3.06 1.77250 49.6
18 -47.639

焦点距離 51.46
Fナンバー 1.85
半画角（度） 22.80
像高 21.64
レンズ全長 77.52
BF 37.85

第１サブレンズ群（第９面〜１０面）データ
ｆｉｓ -39.80
(Numerical Example 3)
Surface data surface number rd nd νd
1 29.364 4.85 1.80 100 35.0
2 83.620 0.20
3 24.070 2.92 1.85026 32.3
4 34.438 1.71
5 54.257 1.10 1.84666 23.8
6 16.006 2.98
7 43.536 2.64 1.77250 49.6
8 -428.522 2.16
9 -103.621 0.80 1.78590 44.2
10 44.955 2.89
11 -1088.042 1.75 1.74 100 52.6
12 -78.891 0.80
13 (Aperture) ∞ 5.39
14 -14.681 1.37 1.64769 33.8
15 -120.986 4.85 1.77250 49.6
16 -18.870 0.20
17 451.320 3.06 1.77250 49.6
18 -47.639

Focal length 51.46
F number 1.85
Half angle of view (degrees) 22.80
Statue height 21.64
Total lens length 77.52
BF 37.85

First sub lens group (9th-10th surfaces) data fis -39.80

（数値実施例４）
面データ
面番号 r d nd νd
1 25.002 1.50 1.60311 60.6
2 15.552 14.16
3 ∞ 3.29
4 55.026 6.05 1.80100 35.0
5 -29.835 1.20 1.76182 26.5
6 144.248 3.03
7 92.760 5.11 1.83481 42.7
8 -21.010 0.80 1.53172 48.8
9 -102.828 1.11
10(絞り) ∞ 2.25
11 -200.259 0.80 1.69680 55.5
12 51.869 5.65
13 -14.694 1.14 1.80518 25.4
14 -16196.496 4.19 1.83481 42.7
15 -21.998 0.20
16* -128.085 3.24 1.77250 49.6
17 -26.500

非球面データ
第16面
Ｂ=-8.67232e-006 C=-6.94338e-010 D= 7.39998e-011 E=-1.10740e-012
F= 4.06278e-015

焦点距離 35.70
Fナンバー 2.05
半画角（度） 31.22
像高 21.64
レンズ全長 91.60
BF 37.89

第１サブレンズ群（第１１面〜１２面）データ
ｆｉｓ -59.05
(Numerical example 4)
Surface data surface number rd nd νd
1 25.002 1.50 1.60311 60.6
2 15.552 14.16
3 ∞ 3.29
4 55.026 6.05 1.80 100 35.0
5 -29.835 1.20 1.76182 26.5
6 144.248 3.03
7 92.760 5.11 1.83481 42.7
8 -21.010 0.80 1.53172 48.8
9 -102.828 1.11
10 (Aperture) ∞ 2.25
11 -200.259 0.80 1.69680 55.5
12 51.869 5.65
13 -14.694 1.14 1.80518 25.4
14 -16196.496 4.19 1.83481 42.7
15 -21.998 0.20
16 * -128.085 3.24 1.77250 49.6
17 -26.500

Aspheric data 16th surface B = -8.67232e-006 C = -6.94338e-010 D = 7.39998e-011 E = -1.10740e-012
F = 4.06278e-015

Focal length 35.70
F number 2.05
Half angle of view (degrees) 31.22
Statue height 21.64
Total lens length 91.60
BF 37.89

First sub lens group (11th to 12th surfaces) data fis -59.05

（数値実施例５）
面データ
面番号 r d nd νd
1 82.181 1.53 1.60311 60.6
2 31.400 2.04
3 40.057 4.26 1.77250 49.6
4 89.295 9.01
5 34.650 1.50 1.72000 43.7
6 16.891 10.78
7 30.950 4.54 1.79952 42.2
8 -81.759 1.10 1.56732 42.8
9 34.823 4.99
10(絞り) ∞ 0.79
11 56.191 7.03 1.83481 42.7
12 -19.113 0.99 1.67270 32.1
13 -57.655 1.13
14 -435.433 0.80 1.72916 54.7
15 52.924 6.18
16 -15.331 0.90 1.76182 26.5
17 -475.690 4.12 1.83481 42.7
18 -21.757 0.20
19* -68.634 3.10 1.58313 59.4
20 -22.874

非球面データ
第19面
B=-1.74908e-005 C= 3.89283e-008 D=-7.05967e-010 E= 4.49232e-012 F=-1.18058e-014

焦点距離 35.00
Fナンバー 2.05
半画角（度） 31.72
像高 21.64
レンズ全長 102.88
BF 37.87

第１サブレンズ群（第１４面〜１５面）データ
ｆｉｓ -64.67
(Numerical example 5)
Surface data surface number rd nd νd
1 82.181 1.53 1.60311 60.6
2 31.400 2.04
3 40.057 4.26 1.77250 49.6
4 89.295 9.01
5 34.650 1.50 1.72000 43.7
6 16.891 10.78
7 30.950 4.54 1.79952 42.2
8 -81.759 1.10 1.56732 42.8
9 34.823 4.99
10 (Aperture) ∞ 0.79
11 56.191 7.03 1.83481 42.7
12 -19.113 0.99 1.67270 32.1
13 -57.655 1.13
14 -435.433 0.80 1.72916 54.7
15 52.924 6.18
16 -15.331 0.90 1.76182 26.5
17 -475.690 4.12 1.83481 42.7
18 -21.757 0.20
19 * -68.634 3.10 1.58313 59.4
20 -22.874

Aspheric data 19th surface
B = -1.74908e-005 C = 3.89283e-008 D = -7.05967e-010 E = 4.49232e-012 F = -1.18058e-014

Focal length 35.00
F number 2.05
Half angle of view (degrees) 31.72
Statue height 21.64
Total lens length 102.88
BF 37.87

First sub lens group (14th to 15th surfaces) data fis -64.67

ＬＦ前側レンズ群ＬＭ中間レンズ群ＬＲ後側レンズ群
Ｌｉｓ第１サブレンズ群Ｌｃ第２サブレンズ群ＳＰ絞り LF Front lens group LM Intermediate lens group LR Rear lens group Lis first sub lens group Lc second sub lens group SP Aperture

Claims

From the front lens group disposed closest to the object side, the intermediate lens group disposed adjacent to the image side of the front lens group, and the rear lens group disposed adjacent to the image side of the intermediate lens group Ru is constructed an optical system,
The intermediate lens group includes a first sub lens group that moves in a direction having a component perpendicular to the optical axis and moves an imaging position in a direction perpendicular to the optical axis, and the first sub lens group. It is composed of a second sub lens group that is arranged adjacent to each other and has a refractive power different from that of the first sub lens group,
The second sub lens group is configured by a single lens or a cemented lens,
The lens surface closest to the object side in the rear lens group is a concave shape, a lens surface on the most image side in the rear lens group is convex,
When the focal length of the first sub lens group is fis and the focal length of the second sub lens group is fc,
0.3 <| fc / fis | <3.5
An optical system that satisfies the following conditional expression:

When the focal length of the entire optical system is f,
0.3 <| fis / f | <3.5
The optical system according to claim 1, wherein the following conditional expression is satisfied.

Among the lenses included in the first sub-lens group and having the same sign as the refractive power of the first sub-lens group, the Abbe based on the d-line of the material of the lens having the smallest absolute value of the focal length. When the number is νdis ,
35 <νdis
The optical system according to claim 1, wherein the following conditional expression is satisfied.

When the lateral magnification of the first sub- lens group when focusing on an object at infinity is βis, and the lateral magnification of the rear lens group when focusing on an object at infinity is βr,
0.2 <| (1-βis) × βr | <2.0
The optical system according to claim 1, wherein the following conditional expression is satisfied.

When the radius of curvature of the lens surface closest to the object side of the first sub lens group is ra and the radius of curvature of the lens surface closest to the image side of the first sub lens group is rb,
−7.0 <(ra + rb) / (ra−rb) <7.0
5. The optical system according to claim 1, wherein the following conditional expression is satisfied.

When the focal length of the entire optical system is f, and the focal length of the intermediate lens group is fm,
0.5 <| fm / f |
The optical system according to claim 1, wherein the following conditional expression is satisfied.

The distance on the optical axis from the lens surface closest to the object side to the lens surface closest to the image side of the first sub lens group is Tis, and the distance from the lens surface closest to the object side to the lens surface closest to the image side of the intermediate lens group When the distance on the optical axis is Tm and the distance on the optical axis from the most object side lens surface to the most image side lens surface of the entire optical system is TDL,
0.03 <Tis / Tm <0.80
0.05 <Tm / TDL <0.50
The optical system according to claim 1, wherein the following conditional expression is satisfied.

The distance in the optical axis direction between the first sub- lens group and the second sub- lens group is Disc, and the distance on the optical axis from the lens surface closest to the object side to the lens surface closest to the image side of the first sub- lens group. Is Tis,
0.3 <| Disc / Tis | <5.0
The optical system according to claim 1, wherein the following conditional expression is satisfied.

When the air space in the optical axis direction of the first sub lens group and the second sub lens group is Disc, and the air space in the optical axis direction of the intermediate lens group and the rear lens group is Dmr,
0.8 <| Dmr / Disc | <6.0
The optical system according to claim 1, wherein the following conditional expression is satisfied.

Further comprising an aperture stop, of the lens surface of the first sub-lens group, a distance on the optical axis from the lens closest surface to the aperture stop to the aperture stop Ds, the most object side of the intermediate lens group When the distance on the optical axis from the lens surface to the lens surface closest to the image is Tm,
0.08 <| Ds / Tm | <2.00
Optical system according to any one of claims 1 to 9, characterized by satisfying the conditional expression.

The rear lens group includes, in order from the object side to the image side, a negative lens having a concave surface on the object side, a positive lens having a convex surface on the image side, and a positive lens having a convex surface on the image side. The optical system according to claim 1, wherein the optical system is an optical system.

The rear lens group, claims 1 to 11, characterized in that the positive refractive power off direction from the optical axis to the periphery of the lens has a lens surface of aspherical shape formed in the weak Kunar so The optical system according to any one of the above.

It said front lens group comprises, in order from the object side to the image side, wherein the two positive lenses of the object-side surface is convex, the surface on the image side are configured Ri by negative lens concave The optical system according to any one of claims 1 to 12.

The front lens group includes, in order from the object side to the image side, two positive lenses having a convex surface on the object side, a negative lens having a concave surface on the image side, and a positive lens. The optical system according to any one of claims 1 to 12.

The front lens group includes, in order from the object side to the image side, a negative lens having a convex surface on the object side and a meniscus shape, and a cemented lens in which a positive lens and a negative lens are cemented. The optical system according to any one of 1 to 12.

It said front lens group comprises, in order from the object side to the image side, a negative lens, the a sub lens unit composed of a positive lens of the lens surface is convex on the object side of the meniscus surface on the object side with a convex object Consists of a negative meniscus lens having a convex surface, a b-th sub- lens group composed of a cemented lens in which a positive lens and a negative lens are cemented, and the b-th sub- lens group and the intermediate lens group during focusing The optical system according to any one of claims 1 to 12, wherein the rear lens group moves.

An optical system according to any one of claims 1 to 16, an imaging apparatus characterized by having an imaging action for receiving an image formed by the optical system.