JPH08146295A - Rear focus type zoom lens - Google Patents
Rear focus type zoom lensInfo
- Publication number
- JPH08146295A JPH08146295A JP6307014A JP30701494A JPH08146295A JP H08146295 A JPH08146295 A JP H08146295A JP 6307014 A JP6307014 A JP 6307014A JP 30701494 A JP30701494 A JP 30701494A JP H08146295 A JPH08146295 A JP H08146295A
- Authority
- JP
- Japan
- Prior art keywords
- lens
- group
- lens group
- refractive power
- wide
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B15/00—Optical objectives with means for varying the magnification
- G02B15/14—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective
- G02B15/16—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective with interdependent non-linearly related movements between one lens or lens group, and another lens or lens group
- G02B15/163—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective with interdependent non-linearly related movements between one lens or lens group, and another lens or lens group having a first movable lens or lens group and a second movable lens or lens group, both in front of a fixed lens or lens group
- G02B15/167—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective with interdependent non-linearly related movements between one lens or lens group, and another lens or lens group having a first movable lens or lens group and a second movable lens or lens group, both in front of a fixed lens or lens group having an additional fixed front lens or group of lenses
- G02B15/173—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective with interdependent non-linearly related movements between one lens or lens group, and another lens or lens group having a first movable lens or lens group and a second movable lens or lens group, both in front of a fixed lens or lens group having an additional fixed front lens or group of lenses arranged +-+
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B15/00—Optical objectives with means for varying the magnification
- G02B15/14—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective
- G02B15/145—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective having five groups only
- G02B15/1451—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective having five groups only the first group being positive
- G02B15/145121—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective having five groups only the first group being positive arranged +-+-+
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Nonlinear Science (AREA)
- Lenses (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明はリヤーフォーカス式のズ
ームレンズに関し、特に写真用カメラやビデオカメラそ
して放送用カメラ等に用いられる変倍比６、広角端のＦ
ナンバー１．８程度の大口径比で高変倍比でしかも広画
角のレンズ全長の短いリヤーフォーカス式のズームレン
ズに関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rear focus type zoom lens, and more particularly to a zoom ratio of 6 and a wide-angle end F lens used for photographic cameras, video cameras, broadcast cameras and the like.
The present invention relates to a rear focus type zoom lens with a large aperture ratio of about 1.8, a high zoom ratio, a wide angle of view, and a short overall lens length.
【０００２】[0002]
【従来の技術】最近、ホームビデオカメラ等の小型軽量
化に伴い、撮像用のズームレンズの小型化にもめざまし
い進歩が見られ、特にレンズ全長の短縮化や前玉径の小
型化、構成の簡略化に力が注がれている。2. Description of the Related Art Recently, with the reduction in size and weight of home video cameras and the like, remarkable progress has been made in the downsizing of zoom lenses for image pickup. Especially, the total lens length is shortened and the front lens diameter is reduced. The effort is focused on simplification.
【０００３】これらの目的を達成するひとつの手段とし
て、物体側の第１群以外のレンズ群を移動させてフォー
カスを行う、所謂リヤーフォーカス式のズームレンズが
知られている。As one means for achieving these objects, there is known a so-called rear focus type zoom lens in which a lens unit other than the first lens unit on the object side is moved to perform focusing.
【０００４】一般にリヤーフォーカス式のズームレンズ
は第１群を移動させてフォーカスを行うズームレンズに
比べて第１群の有効径が小さくなり、レンズ系全体の小
型化が容易になり、又近接撮影、特に極近接撮影が容易
となり、更に比較的小型軽量のレンズ群を移動させて行
っているので、レンズ群の駆動力が小さくてすみ迅速な
焦点合わせが出来る等の特長がある。Generally, in a rear focus type zoom lens, the effective diameter of the first lens group is smaller than that of a zoom lens in which the first lens group is moved to perform focusing, which facilitates downsizing of the entire lens system and close-up photography. Especially, it is easy to perform extremely close-up photography, and since the relatively small and lightweight lens group is moved, the driving force of the lens group is small and quick focusing is possible.
【０００５】このようなリヤーフォーカス式のズームレ
ンズが、例えば特開平５−２１５９６７号公報で提案さ
れている。同公報では物体側より順に変倍中固定の正の
屈折力の第１群、変倍用の負の屈折力の第２群、正の屈
折力の第３群、負の屈折力の第４群、そして変倍に伴う
像面変動を補正する為の正の屈折力の第５群の５つのレ
ンズ群より成り、変倍に際して第３群と第４群の少なく
とも１つを移動させると共に、フォーカスの際に第５群
を移動させた、リヤーフォーカス式のズームレンズを提
案している。Such a rear focus type zoom lens is proposed in, for example, Japanese Patent Laid-Open No. 5-215967. In the same publication, in order from the object side, a first group of positive refractive power which is fixed during zooming, a second group of negative refractive power for zooming, a third group of positive refractive power, and a fourth group of negative refractive power. A lens unit and five lens units of a fifth lens unit having a positive refractive power for correcting the image plane variation due to zooming, and at least one of the third lens unit and the fourth lens unit is moved during zooming, We have proposed a rear-focus type zoom lens that moves the fifth lens group during focusing.
【０００６】[0006]
【発明が解決しようとする課題】一般にズームレンズに
おいてリヤーフォーカス方式を採用するとレンズ系全体
が小型化され、又迅速なるフォーカスが可能となり、更
に近接撮影が容易となる等の特長が得られる。Generally, when a rear focus system is adopted in a zoom lens, the entire lens system can be downsized, quick focusing can be performed, and close-up shooting can be facilitated.
【０００７】しかしながら反面、フォーカスの際の収差
変動が大きくなり、無限遠物体から近距離物体に至る物
体距離全般にわたりレンズ系全体の小型化を図りつつ高
い光学性能を得るのが大変難しくなるという問題点が生
じてくる。On the other hand, however, the aberration variation during focusing becomes large, and it becomes very difficult to obtain high optical performance while miniaturizing the entire lens system over the entire object distance from an infinite object to a short-distance object. Dots come up.
【０００８】特に大口径比で高変倍のズームレンズでは
全変倍範囲にわたり、又物体距離全般にわたり高い光学
性能を得るのが大変難しくなるという問題点が生じてく
る。Particularly, in a zoom lens having a large aperture ratio and a high zoom ratio, it becomes very difficult to obtain high optical performance over the entire zoom range and the entire object distance.
【０００９】先に提案された特開平５−２１５９６７号
公報におけるリヤーフォーカス式のズームレンズでは比
較的高変倍比を有しているが変倍に際して３つのレンズ
群を移動させている為に機構構成が複雑化してレンズ系
全体が大型化してくる傾向があった。The rear focus type zoom lens proposed in Japanese Patent Laid-Open No. 5-215967 has a relatively high zoom ratio, but the three lens groups are moved during zooming so that the mechanism is changed. There is a tendency that the entire system becomes large due to the complicated structure.
【００１０】又像面近傍の比較的高重量の第５群を変倍
及びフォーカスの際に移動させている為、ＣＣＤ等の固
体撮像素子やフィルム近傍の機構構成が複雑になり、ゴ
ミ等が付着してくること、変倍及びフォーカスの際のモ
ータへの負荷が大きくなること、等の問題点があった。Further, since the fifth group, which has a relatively high weight in the vicinity of the image plane, is moved during zooming and focusing, the solid-state image pickup device such as CCD and the mechanical structure in the vicinity of the film are complicated, and dust and the like are generated. However, there are problems such as adhesion, increased load on the motor during zooming and focusing.
【００１１】本発明は、リヤーフォーカス方式を採用し
つつ、大口径比化、広画角化及び変倍比６程度の高変倍
化、そして前玉径の縮小化を図り、レンズ系全体の小型
化を図りつつ、広角端から望遠端に至る全変倍範囲にわ
たり、又無限遠物体から近距離物体に至る物体距離全般
にわたり、良好なる光学性能を有した、特に広角端にお
ける歪曲収差を良好に補正した簡易な構成のリヤーフォ
ーカス式のズームレンズの提供を目的とする。According to the present invention, while adopting the rear focus system, a large aperture ratio, a wide angle of view, a high zoom ratio of about 6 and a reduction of the front lens diameter are achieved, and the entire lens system is improved. While achieving downsizing, it has good optical performance over the entire zoom range from the wide-angle end to the telephoto end, and over the entire object distance from infinity objects to short-distance objects, particularly good distortion at the wide-angle end. It is an object of the present invention to provide a rear focus type zoom lens having a simple structure corrected to the above.
【００１２】[0012]
【課題を解決するための手段】本発明のリヤーフォーカ
ス式のズームレンズは、物体側より順に正の屈折力の第
１群、負の屈折力の第２群、正の屈折力の第３群、負の
屈折力の第４群、そして正の屈折力の第５群の５つのレ
ンズ群を有し、該第２群を像面側へ移動させて広角端か
ら望遠端への変倍を行い、変倍に伴う像面変動を該第４
群を移動させて補正すると共に該第４群を光軸上移動さ
せてフォーカスを行い、該第３群を正の単一レンズより
構成したことを特徴としている。A rear focus type zoom lens according to the present invention comprises a first group having a positive refractive power, a second group having a negative refractive power, and a third group having a positive refractive power in order from the object side. , A fifth lens unit having a negative refracting power and a fifth lens unit having a positive refracting power, and moving the second lens unit toward the image side to change the magnification from the wide-angle end to the telephoto end. The image plane variation due to zooming
It is characterized in that the fourth group is moved on the optical axis for focusing while the group is moved for correction, and the third group is composed of a single positive lens.
【００１３】[0013]
【実施例】図１（Ａ）は本発明のリヤーフォーカス式の
ズームレンズの近軸屈折力配置を示す一実施例の概略図
である。図２〜図７は本発明の後述する数値実施例１〜
６のレンズ断面図、図８〜図１９は本発明の後述する数
値実施例１〜６の諸収差図である。収差図において
（Ａ）は広角端、（Ｂ）は望遠端を示している。DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1A is a schematic view of an embodiment showing a paraxial refractive power arrangement of a rear focus type zoom lens of the present invention. 2 to 7 are numerical examples 1 to be described later of the present invention.
6 is a lens sectional view, and FIGS. 8 to 19 are various aberration diagrams of Numerical Examples 1 to 6 described later of the present invention. In the aberration diagrams, (A) shows the wide-angle end and (B) shows the telephoto end.
【００１４】図中、Ｌ１は正の屈折力の第１群（第１レ
ンズ群）、Ｌ２は負の屈折力の第２群（第２レンズ
群）、Ｌ３は正の屈折力の第３群（第３レンズ群）、Ｌ
４は負の屈折力の第４群（第４レンズ群）、Ｌ５は正の
屈折力の第５群（第５レンズ群）である。ＳＰは開口絞
りであり、第３群Ｌ３の前方に配置している。ＩＰは像
面である。In the figure, L1 is a first lens group (first lens group) having a positive refractive power, L2 is a second lens group (second lens group) having a negative refractive power, and L3 is a third lens group having a positive refractive power. (Third lens group), L
Reference numeral 4 denotes a fourth group (fourth lens group) having a negative refractive power, and L5 denotes a fifth group (fifth lens group) having a positive refractive power. SP is an aperture stop, which is arranged in front of the third lens unit L3. IP is the image plane.
【００１５】広角端から望遠端への変倍に際して矢印の
ように第２群を像面側へ移動させると共に、変倍に伴う
像面変動を第４群を像面側に凸状の軌跡を有しつつ移動
させて補正している。又、第４群を光軸上移動させてフ
ォーカスを行うリヤーフォーカス式を採用している。At the time of zooming from the wide-angle end to the telephoto end, the second lens unit is moved to the image plane side as indicated by an arrow, and the image surface variation caused by zooming is caused by a convex locus of the fourth lens unit on the image plane side. It is corrected while moving while having it. Also, a rear focus type is adopted in which focusing is performed by moving the fourth lens unit on the optical axis.
【００１６】同図に示す第４群の実線の曲線４ａと点線
の曲線４ｂは各々無限遠物体と近距離物体にフォーカス
しているときの広角端から望遠端への変倍に伴う際の像
面変動を補正する為の移動軌跡を示している。第１群，
第３群，第５群は変倍及びフォーカスの際、固定であ
る。The solid curve 4a and the dotted curve 4b of the fourth group shown in the same figure are images at the time of zooming from the wide-angle end to the telephoto end when focusing on an object at infinity and a near object, respectively. The movement locus for correcting the surface variation is shown. The first group,
The third and fifth groups are fixed during zooming and focusing.
【００１７】本実施例においては、第４群を移動させて
変倍に伴う像面変動の補正を行うと共に第４群を移動さ
せてフォーカスを行うようにしている。特に同図の曲線
４ａ，４ｂに示すように広角端から望遠端への変倍に際
して像面側へ凸状の軌跡を有するように移動させてい
る。これにより第４群と第５群との空気の有効利用を図
りレンズ全長の短縮化を効果的に達成している。In the present embodiment, the fourth lens group is moved to correct the image plane variation due to zooming, and the fourth lens group is moved to perform the focusing. In particular, as shown by the curves 4a and 4b in the figure, when the magnification is changed from the wide-angle end to the telephoto end, it is moved so as to have a convex locus toward the image plane side. As a result, the air of the fourth group and the fifth group is effectively used and the total lens length is effectively shortened.
【００１８】本実施例において、例えば望遠端において
無限遠物体から近距離物体へフォーカスを行う場合は、
同図の直線４ｃに示すように第４群を後方（像面側）へ
繰り込むことにより行っている。In this embodiment, for example, when focusing on an object at infinity from a near object at the telephoto end,
As shown by the straight line 4c in the figure, this is done by retracting the fourth lens unit rearward (on the image plane side).
【００１９】一般に第１レンズ群を光軸上移動させて距
離合わせを行う、所謂前玉フォーカス方式が知られてい
るが、この方式は広角側で至近距離撮影時に周辺画面に
光束を確保するために前玉径が大きくなりがちとなる。
この為、このフォーカス方式では、本発明の目的の１つ
である小型化は難しくなる。この際、構成上最も径の大
きい第１レンズ群はズーミング中固定になっている方
が、機構上の簡略化のためにも良い。In general, a so-called front lens focus system is known in which the first lens group is moved along the optical axis to perform distance adjustment. However, this system secures a light flux on the peripheral screen during wide-angle shooting at close range. The front lens diameter tends to increase.
Therefore, with this focus method, it is difficult to achieve miniaturization, which is one of the objects of the present invention. At this time, it is preferable that the first lens group having the largest diameter in the configuration is fixed during zooming for the sake of simplification of the mechanism.
【００２０】そこで第３レンズ群以降に配置されたレン
ズ群、特に第４レンズ群でフォーカシングを行うものが
小型化を目的とする際には好ましい。また絞りユニット
を有する第３レンズ群も固定である方が機構上の簡略化
には好ましい。特に絞りユニットを有する第３レンズ群
は単レンズで構成すると絞りユニット周辺の機構は小型
になり、組立においても簡単になる。又第４レンズ群の
可動スペースを確保するためにも好ましい。Therefore, a lens unit arranged after the third lens unit, particularly one in which focusing is performed by the fourth lens unit, is preferable for the purpose of downsizing. Further, it is preferable that the third lens group having the diaphragm unit is also fixed for the simplification of the mechanism. In particular, if the third lens group having the diaphragm unit is composed of a single lens, the mechanism around the diaphragm unit becomes small and the assembly becomes easy. It is also preferable to secure a movable space for the fourth lens group.
【００２１】特に第４レンズ群は、広角端より中間ズー
ムまでの変倍領域にかけて像面側に移動するのが好まし
い。更に高変倍のズームレンズを構成するには第４レン
ズ群は広角端より望遠端にかけて像面側に凸の軌跡で移
動し、又特に略完全往復していればスペース効率が良
く、小型の高変倍ズームレンズが可能となる。この時特
に第２レンズ群のズーミング中の横倍率は等倍（−１）
を挟んで変化している構成にするのが良い。次にこの構
成で前玉径が小型化できる技術的意味を説明する。In particular, it is preferable that the fourth lens group moves toward the image plane side in the variable power range from the wide-angle end to the intermediate zoom. In order to construct a zoom lens with a high zoom ratio, the fourth lens group moves in a convex locus toward the image plane from the wide-angle end to the telephoto end, and particularly if it makes a complete round trip, it is space-efficient and compact. A high-magnification zoom lens becomes possible. At this time, especially the lateral magnification during zooming of the second lens group is equal to (-1).
It is better to have a structure that changes across Next, the technical meaning of reducing the front lens diameter with this configuration will be described.
【００２２】従来より広角化を図ろうとすると、広角端
寄りの中間ズーム位置において第１レンズ群への軸外光
束の入射高が高くなり、この結果、第１レンズ群のレン
ズ有効径が増大してくる。この前玉径の増大を防止する
には上記中間ズーム位置で物体側より瞳（絞り）へ入射
する軸外光束の入射角度θを浅めに（小さめに）設定す
るように構成するのが良い。その為には上述したように
第４レンズ群は広角端より中間ズーム域にかけて像面側
に移動するのが好ましい。If an attempt is made to widen the angle compared to the conventional case, the height of incidence of the off-axis light beam on the first lens group increases at the intermediate zoom position near the wide-angle end, and as a result, the lens effective diameter of the first lens group increases. Come on. In order to prevent the increase of the front lens diameter, it is preferable to set the incident angle θ of the off-axis light beam entering the pupil (diaphragm) from the object side at the intermediate zoom position to be shallow (small). Therefore, as described above, it is preferable that the fourth lens group moves toward the image plane side from the wide-angle end to the intermediate zoom range.
【００２３】この様に構成することにより、前玉径を決
定する焦点距離はかなり望遠側に寄り、径の小型化が可
能になる。このとき、特に全ズーム域でレンズの射出瞳
位置は像面よりプラス側（像面より反物体側）にあるの
が有効である。With this configuration, the focal length that determines the front lens diameter is considerably closer to the telephoto side, and the diameter can be reduced. At this time, in particular, it is effective that the exit pupil position of the lens is on the plus side of the image plane (opposite the object side of the image plane) in the entire zoom range.
【００２４】このことを図１（Ａ）に従って検証する。
図１（Ａ）は広角端から少し望遠側に寄った中間ズーム
の位置で、第１レンズの有効径を決定する焦点距離の位
置である。同時に図１（Ｂ）に参考の為に特開昭６２−
２４２１３号公報で開示されているズームレンズの近軸
屈折力配置を示す。像面側から物体側へ軸外光束の光線
を逆追跡すると、第４レンズ群に強い負のパワーがある
ために像面側からでる軸外光束は射出瞳が、ややプラス
側に寄っている。この光束が第５レンズ群で絞りＳＰ側
に曲げられ更に第４レンズ群で絞りＳＰを有する第３レ
ンズ群にゆるやかな角度で入っていく。この絞りＳＰを
通過する角度θが従来のズームレンズよりもゆるくでき
る為結果的に第１レンズの径を小さくできるのである。This will be verified according to FIG.
FIG. 1A shows the position of the intermediate zoom slightly closer to the telephoto side from the wide-angle end, and the position of the focal length that determines the effective diameter of the first lens. At the same time, as shown in FIG.
The paraxial refractive power arrangement of the zoom lens disclosed in Japanese Patent No. 24213 is shown. When the ray of the off-axis light flux is traced back from the image plane side to the object side, the exit pupil of the off-axis light flux emerging from the image plane side is slightly shifted to the plus side because the fourth lens group has a strong negative power. . This light flux is bent toward the diaphragm SP by the fifth lens group and further enters the third lens group having the diaphragm SP at the fourth lens group at a gentle angle. The angle θ passing through the diaphragm SP can be made smaller than that of the conventional zoom lens, and as a result, the diameter of the first lens can be reduced.
【００２５】このように本発明では、射出瞳位置が像面
からプラス側（反物体側）にあるのが好ましい。少なく
とも前玉径の決定に寄与する広角端ではプラス側になっ
ている事が好ましい。As described above, in the present invention, it is preferable that the exit pupil position is on the plus side (anti-object side) from the image plane. At least at the wide-angle end that contributes to the determination of the front lens diameter, it is preferably on the plus side.
【００２６】本発明の目的とするリヤーフォーカス式の
ズームレンズは以上の諸条件を満足させることにより達
成することができるが、更にレンズ系全体の小型化を図
りつつ、高変倍化を図る際の変倍に伴なう収差変動を少
なくし、全変倍範囲にわたり高い光学性能を得るには次
の諸条件のうち少なくとも１つを満足させるのが良い。The rear focus type zoom lens, which is the object of the present invention, can be achieved by satisfying the above-mentioned conditions. However, in order to further reduce the size of the entire lens system and achieve a high zoom ratio, It is preferable to satisfy at least one of the following conditions in order to reduce the aberration variation associated with zooming and to obtain high optical performance over the entire zooming range.
【００２７】（１−１）第ｉレンズ群の焦点距離をＦ
ｉ、全系の広角端の焦点距離距離をＦｗとすると以下の
条件式を満たしている事が好ましい。(1-1) The focal length of the i-th lens unit is F
It is preferable that the following conditional expression is satisfied, where i is the focal length at the wide-angle end of the entire system and is Fw.
【００２８】 ４＜Ｆ１／Ｆｗ＜６．５ ‥‥‥（１） この条件は、本発明の様に小型化や機構の簡略化をしな
がら６倍程度のズームレンズを設定するのに必要な式で
ある。この式は第２レンズ群に対する物点、即ち倍率に
係わる式である。全系を小さく設定するには、第２レン
ズ群がズーミングに際して等倍を挟んでいるのが好まし
い。等倍を挟むと第４レンズ群のズーミングの軌跡は略
往復になり、最も効果的なスペース効率で高変倍が可能
となる。具体的には、この式の上限値を越えると第１レ
ンズ群の焦点距離が長くなり、主変倍レンズ群である第
２レンズ群に対する物点が遠くなり、第２レンズ群の結
像倍率が低くなり、効果的な小型化が難しくなる。更
に、第１レンズ群と第２レンズ群の間隔が大きくなり小
型化の達成が難しくなる。4 <F1 / Fw <6.5 (1) This condition is necessary to set a zoom lens of about 6 times while reducing the size and simplifying the mechanism as in the present invention. It is an expression. This equation relates to the object point for the second lens group, that is, the magnification. In order to set the whole system small, it is preferable that the second lens group sandwich the same magnification during zooming. When the same magnification is sandwiched, the locus of zooming of the fourth lens group becomes a substantially reciprocating movement, and high zooming is possible with the most effective space efficiency. Specifically, if the upper limit of this expression is exceeded, the focal length of the first lens group becomes long, the object point with respect to the second lens group that is the main variable power lens group becomes far, and the imaging magnification of the second lens group increases. Becomes low, and effective miniaturization becomes difficult. Furthermore, the distance between the first lens group and the second lens group becomes large, which makes it difficult to achieve miniaturization.
【００２９】又下限値を越えると第１レンズ群の焦点距
離が短くなり、第２レンズ群の結像横倍率を上述したよ
うに確保しようとすると、第２レンズ群の屈折力が強く
なり保持精度が厳しくなり適当でない。If the lower limit is exceeded, the focal length of the first lens group becomes short, and if the image formation lateral magnification of the second lens group is to be secured as described above, the refracting power of the second lens group becomes strong and is kept. Precision becomes severe and not appropriate.
【００３０】（１−２）物体側から順に、ズーミング中
固定の正の屈折力の第１レンズ群、ズーミング中可動の
負の屈折力の第２レンズ群、正の屈折力の第３レンズ
群、ズーミングに伴う像点の移動を補正する負の屈折力
の第４レンズ群、正の第５レンズ群の順の構成におい
て、距離合わせを第４レンズ群で行うことが好ましい。
この際、第４レンズ群は近距離に距離合わせ（フォーカ
シング）するときは像面側に繰り込むように構成するの
が良い。このように負の第４レンズ群を繰り込んで距離
合わせを行うと、従来のような正レンズ群で行うリヤー
フォーカス方式の様に近軸的な変倍比に対して近距離側
で変倍比が小さくなることがなく、高変倍化しても近距
離側で所望の変倍比が得られる。(1-2) In order from the object side, the first lens group having a positive refractive power which is fixed during zooming, the second lens group having a negative refractive power which is movable during zooming, and the third lens group having a positive refractive power. In the order of the fourth lens unit having a negative refractive power for correcting the movement of the image point due to zooming and the fifth lens unit having a positive refractive power, it is preferable that the fourth lens unit performs the distance matching.
At this time, it is preferable that the fourth lens group is configured to be retracted to the image plane side when the distance is adjusted (focusing) to a short distance. When the negative fourth lens group is retracted in this way to perform distance adjustment, the zooming is performed on the short-distance side with respect to the paraxial zooming ratio as in the conventional rear focus method using the positive lens group. The ratio does not decrease, and a desired zoom ratio can be obtained on the short distance side even if the zoom ratio is increased.
【００３１】（１−３）前玉径の小型化に関係する絞り
ＳＰの位置は、望遠端において第３レンズ群の近傍に配
置するのが良い。この時広角側において、絞りＳＰの位
置は望遠端での位置よりも物体側にあるように移動して
も前玉径の小型化に有効である。(1-3) The position of the aperture stop SP related to the reduction of the front lens diameter is preferably located near the third lens group at the telephoto end. At this time, on the wide angle side, even if the position of the aperture stop SP is moved to be closer to the object side than the position at the telephoto end, it is effective in reducing the front lens diameter.
【００３２】一般に従来のズームレンズでは、第１レン
ズ群への軸外光束の入射高は、入射瞳が第１レンズ群か
ら深い所（奥まったところ）にあるため、広角端寄りの
中間ズーム位置で最も高くなる。この入射高の最も高い
位置を、入射瞳即ち絞りＳＰを移動させることにより、
広角端近傍に設定できれば第１レンズ群の外径を最も効
率的に小さくできる。Generally, in a conventional zoom lens, the height of incidence of the off-axis light beam on the first lens group is deep (rear) from the first lens group, so that the intermediate zoom position near the wide-angle end. Will be the highest. By moving the entrance pupil, that is, the stop SP, at the highest position of this incident height,
If it can be set near the wide-angle end, the outer diameter of the first lens group can be most efficiently reduced.
【００３３】特に絞りＳＰは、第３レンズ群近傍にズー
ミング中固定である方が機構構成上は好ましい。このと
き絞りＳＰは第３レンズ群の近傍にあるのが良い。特に
前玉径の小型化には第３レンズ群の比較的物体側、好ま
しくは最も物体側には位置させるのが良い。In particular, the diaphragm SP is preferably fixed in the vicinity of the third lens unit during zooming in view of the mechanical structure. At this time, it is preferable that the diaphragm SP be near the third lens group. In particular, in order to reduce the diameter of the front lens, it is preferable to position the third lens group relatively on the object side, preferably on the most object side.
【００３４】（１−４）広角端において、物体距離無限
遠での第２レンズ群と第３レンズ群の間隔（絞りが第３
レンズ群の物体側にある場合は、絞り面まで）をＤ２
ｗ、第４レンズ群と第５レンズ群の間隔をＤ４ｗとする
と以下の式を満足しているのが好ましい。(1-4) At the wide-angle end, the distance between the second lens group and the third lens group at the infinite object distance (the aperture is the third
If it is on the object side of the lens group, up to the diaphragm surface) D2
If w and the distance between the fourth lens group and the fifth lens group are D4w, it is preferable to satisfy the following formula.
【００３５】 １．５＜Ｄ２ｗ／Ｄ４ｗ＜２．９ ‥‥‥（２） この式は、望遠端になれば増加する第４レンズ群のフォ
ーカス移動量の為の間隔を、主変倍レンズ群である第２
レンズ群の移動範囲との関係で規定しているものであ
る。1.5 <D2w / D4w <2.9 (2) This equation defines the interval for the focus movement amount of the fourth lens group that increases at the telephoto end as the main variable power lens group. Is the second
It is defined in relation to the moving range of the lens group.
【００３６】このようなリヤーフォーカス方式をとるズ
ームレンズの場合、どうしても望遠端の近距離のフォー
カレンズ移動量が大きくなる。特にズームの倍率が大き
くなればなるほど、第４レンズ群の像面位置補正の移動
量・フォーカスの為の移動量が共に大きくなる間隔，Ｄ
２ｗが大きい、即ちズーミングのための移動範囲が大き
いとズーム比が大きくなり、所望の至近撮影距離の為の
第４レンズ群の移動量が望遠端で大きくする必要があ
る。その相関を示したものである。上限値を越えると、
望遠端で至近距離が遠くなり適当でない。又下限値を越
えると、ズーム比の小さなズームレンズとなり適当でな
い。In the case of a zoom lens adopting such a rear focus system, the amount of movement of the focus lens at a short distance at the telephoto end is inevitably large. In particular, as the zoom magnification increases, the distance by which the moving amount for image plane position correction of the fourth lens unit and the moving amount for focusing both increase, D,
If 2w is large, that is, if the moving range for zooming is large, the zoom ratio becomes large, and the moving amount of the fourth lens group for the desired close-up shooting distance needs to be large at the telephoto end. It shows the correlation. When the upper limit is exceeded,
It is not appropriate because the close-up distance becomes too long at the telephoto end. On the other hand, if the value goes below the lower limit, a zoom lens having a small zoom ratio is not suitable.
【００３７】（１−５）フォーカスレンズの移動に関し
ては以下の式を満たしているのが好ましい。(1-5) Regarding the movement of the focus lens, it is preferable that the following expression is satisfied.
【００３８】 ０．３＜｜Ｄ４ｗ／Ｆ４｜＜０．５ ‥‥‥（３） この式は、フォーカスレンズである第４レンズ群の屈折
力と可動間隔を適切に設定したものである。上限値を越
えると所望の至近距離のために必要な間隔以上の間隔を
設定した事となり全長が大型化し適当でない。又下限値
を越えるとフォーカスのための必要な間隔が確保できず
適当でない。0.3 <| D4w / F4 | <0.5 (3) This equation sets the refractive power and the movable distance of the fourth lens group, which is the focus lens, appropriately. If the value exceeds the upper limit, an interval greater than that required for the desired close distance is set, and the total length becomes large, which is not appropriate. On the other hand, when the value is below the lower limit, it is not suitable because the necessary interval for focusing cannot be secured.
【００３９】（１−６）第４レンズ群は、以下の関係を
満たしているのが好ましい。(1-6) The fourth lens group preferably satisfies the following relationship.
【００４０】 −２．６＜Ｆ４／Ｆｗ＜−１．５ ‥‥‥（４） この式の上限値を越えると第４レンズ群の屈折力が強く
なり、ペッツバール和が負の値で大きくなるために、像
面が補正過剰となり適当でない。又下限値を越えると所
望の至近撮影距離を得るために第４レンズ群の移動量が
大きくなり全系が大型化して適当ではない。-2.6 <F4 / Fw <-1.5 (4) If the upper limit of this expression is exceeded, the refracting power of the fourth lens group becomes strong, and the Petzval sum increases at a negative value. Therefore, the image plane is overcorrected, which is not suitable. On the other hand, if the value goes below the lower limit, the movement amount of the fourth lens unit becomes large in order to obtain a desired close-up shooting distance, and the entire system becomes large, which is not suitable.
【００４１】（１−７）ズーミングのための主変倍レン
ズ群である第２レンズ群は、以下の範囲にあると好まし
い。(1-7) The second lens group, which is the main zoom lens group for zooming, is preferably in the following range.
【００４２】 −１．２＞Ｆ２／Ｆｗ＜−０．８ ‥‥‥（５） この式の上限値を越えると第２レンズ群の屈折力が強く
なり、ペッツバール和が負の値で大きくなるために、像
面が補正過剰となり適当でない。又下限値を越えると所
望の変倍比を得るために第２レンズ群の移動量が大きく
なり前玉径及び全系が大型化して適当ではない。-1.2> F2 / Fw <-0.8 (5) If the upper limit of this expression is exceeded, the refracting power of the second lens group will become strong and the Petzval sum will increase at a negative value. Therefore, the image plane is overcorrected, which is not suitable. On the other hand, if the value goes below the lower limit, the amount of movement of the second lens group becomes large in order to obtain a desired zoom ratio, and the front lens diameter and the entire system become large, which is not suitable.
【００４３】（１−８）第３レンズ群には、光束は発散
系で入射し集束系にして第４レンズ群に導くのが良い。
即ちズーム全域で結像倍率β３は常に負の値をもつのが
小型化に適している。(1-8) It is preferable that the light flux is incident on the third lens group by a divergent system and is made a convergent system to be guided to the fourth lens group.
That is, it is suitable for downsizing that the imaging magnification β3 always has a negative value in the entire zoom range.
【００４４】β３＜０ ‥‥‥（６） この式を満たすと、第４レンズ群を効率よく移動させ
る、特に第４レンズ群が広角端より望遠端にかけて像面
側に凸の軌跡で移動し、又特に略完全往復する為に必要
なものであり小型化に有効である。Β3 <0 (6) When this expression is satisfied, the fourth lens group is moved efficiently, and particularly the fourth lens group moves in a convex locus toward the image plane side from the wide-angle end to the telephoto end. Moreover, it is particularly necessary for almost complete reciprocation, and is effective for downsizing.
【００４５】全系を小さくし、移動スペースを有効に設
定するには、第４レンズ群は略完全往復もしくは像面側
に凸の軌跡にしておけば良いのは上述の通りである。そ
のためには、第３レンズ群の結像倍率β３は負の値で、
広角端から望遠端にかけて絶対値が大きくなり更に小さ
くなるのが好ましい。ここで広角端及び望遠端の第３レ
ンズ群の近軸横倍率をそれぞれβ３Ｗ，β３Ｔとすると β３Ｗ≒β３Ｔ であると、最もスペース効率が良い。特に広角端から望
遠端への第３レンズ群の近軸横倍率の絶対値の最大値を
β３ＭＡＸすると ｜β３ＭＡＸ｜＞０．８ ‥‥‥（７） になっているのが良く、更に−１を越えている方が高倍
化に好適である。As described above, in order to reduce the size of the entire system and effectively set the moving space, the fourth lens group should have a substantially complete reciprocating or a locus convex toward the image plane side. For that purpose, the imaging magnification β3 of the third lens group is a negative value,
It is preferable that the absolute value increases from the wide-angle end to the telephoto end and further decreases. Here, assuming that the paraxial lateral magnifications of the third lens unit at the wide-angle end and the telephoto end are β3W and β3T, respectively, β3W≈β3T provides the best space efficiency. In particular, when the maximum absolute value of the paraxial lateral magnification of the third lens unit from the wide-angle end to the telephoto end is β3MAX, | β3MAX |> 0.8 (7) is preferable, and further -1 It is more suitable for higher doubling.
【００４６】（１−９）広角端から望遠端にかけての第
２レンズ群の結像倍率の比（β２Ｔ／β２ｗ）をＺ２、
望遠端における全系の焦点距離をＦｔとし，全系の広角
端と望遠端での焦点距離の比（Ｆｔ／Ｆｗ）をＺとする
と ０．６８＜Ｚ２／Ｚ＜１．０ ‥‥‥（８） を満足している事が好ましい。この式は全体の変倍に対
する第２レンズ群の変倍の割合を示すものである。この
上限値を越えるとレンズ系のどこかの群がズーミング
中、減倍している事になり変倍効率が悪く大型化の原因
となり適当でない。(1-9) The ratio (β2T / β2w) of the imaging magnification of the second lens unit from the wide-angle end to the telephoto end is Z2,
If the focal length of the entire system at the telephoto end is Ft and the ratio (Ft / Fw) of the focal lengths at the wide-angle end and the telephoto end of the entire system is Z, then 0.68 <Z2 / Z <1.0 It is preferable that 8) is satisfied. This expression shows the ratio of the magnification variation of the second lens group to the overall magnification variation. If the value exceeds this upper limit, some lens group in the lens system will be demagnified during zooming, resulting in poor variable power efficiency and an increase in size.
【００４７】また下限値を越えると変倍に寄与するレン
ズ群が複数個有る事になりそれぞれの制御が難しくな
る。特に、第４レンズ群はズーミングにより完全往復し
ていれば最もスペース効率が良いが所望のズーム比を得
るために第４レンズ群は完全に戻らない場合のある。こ
のとき第４レンズ群も若干の変倍に寄与するわけである
が（｜β３Ｗ｜＜｜β３Ｔ｜）、そのときは以下の範囲
にあるのが良い。If the value goes below the lower limit, there are a plurality of lens groups that contribute to zooming, and it becomes difficult to control each of them. In particular, if the fourth lens group reciprocates completely by zooming, the space efficiency is the best, but there are cases where the fourth lens group does not completely return to obtain a desired zoom ratio. At this time, the fourth lens group also contributes to a slight zooming (| β3W | <| β3T |), but in that case, it is preferable that the range is as follows.
【００４８】０．６８＜Ｚ２／Ｚ＜０．８ この範囲を逸脱し、第４レンズ群の変倍寄与が大きくな
ると第４レンズ群の可動スペースが大きくなり、全系が
大型化し適当でない。0.68 <Z2 / Z <0.8 If deviating from this range and the contribution of the fourth lens group to zooming becomes large, the movable space of the fourth lens group becomes large and the entire system becomes large, which is not suitable.
【００４９】（１−１０）また第３レンズ群は、以下の
式を満たしてるのが好ましい。(1-10) Further, it is preferable that the third lens group satisfies the following expression.
【００５０】 １．５＜Ｆ３／Ｆｗ＜２．０ ‥‥‥（９） この式は上述した第３レンズ群の倍率を適切に設定する
為に有効なものである。この上限値を越えると大型化
し、下限値を越えると第４レンズ群のフォーカスのため
の可動間隔を適切に設定できなくなる。1.5 <F3 / Fw <2.0 (9) This equation is effective for appropriately setting the magnification of the third lens group described above. When the upper limit is exceeded, the size becomes large, and when the lower limit is exceeded, the movable interval for focusing the fourth lens group cannot be properly set.
【００５１】この範囲を逸脱すると第４レンズ群を効率
よく移動できず、特に第４レンズ群が広角端より望遠端
にかけて像面側に凸の軌跡で移動し、或いは特に略完全
往復することができなくなる。また第３レンズ群を単レ
ンズで構成する事により小型化を達成しているが、特に
球面収差を軽減するために、第３レンズ群のいずれかの
面に非球面を有していても良い。If the value deviates from this range, the fourth lens group cannot be moved efficiently, and in particular, the fourth lens group may move in a convex locus toward the image plane side from the wide-angle end to the telephoto end, or may substantially reciprocate. become unable. Although the third lens group is made of a single lens to achieve miniaturization, any surface of the third lens group may have an aspherical surface in order to reduce spherical aberration. .
【００５２】（１−１１）フォーカスレンズ群であり、
像点の補正レンズ群である第４レンズ群は可動するため
小さく軽い構成の方が小型化、機構の簡略かには好まし
い。そのためには第４レンズ群は負の単レンズで構成し
ているのが好ましい。このときフォーカス及びズームで
の色収差の変動を押さえるため、以下の関係を満たすの
がよい。(1-11) Focus lens group,
Since the fourth lens group, which is an image point correcting lens group, is movable, a small and light structure is preferable for downsizing and simplification of the mechanism. For that purpose, it is preferable that the fourth lens unit be composed of a negative single lens. At this time, in order to suppress variation in chromatic aberration during focusing and zooming, it is preferable to satisfy the following relationship.
【００５３】２０＜ν４＜５０ ‥‥‥（１０） ここでν４は第４レンズ群を構成するレンズのアッベ数
である。またこの時、第４レンズ群を構成する単レンズ
の屈折は以下の範囲にあるのが良い。20 <ν4 <50 (10) Here, ν4 is the Abbe number of the lenses constituting the fourth lens group. At this time, the refraction of the single lens forming the fourth lens group should be in the following range.
【００５４】１．６５＜Ｎ４ ‥‥‥（１１） ここでＮ４は第４レンズ群を構成するレンズの屈折率で
ある。この範囲を逸脱すると、上述した範囲の焦点距離
Ｆ４にするためには曲率Ｒがきつくなり収差の劣化が著
しくなり適当でない。1.65 <N4 (11) Here, N4 is the refractive index of the lenses constituting the fourth lens group. If it deviates from this range, the curvature R becomes too tight and the deterioration of aberration becomes remarkable in order to obtain the focal length F4 in the above range, which is not suitable.
【００５５】特に、第４レンズ群を単レンズ（あるいは
貼り合わせ等の１ブロック）で構成するとき、このレン
ズは両凹レンズである事が好ましい。その物体側及び像
面側の曲率半径をそれぞれＲ４ａ，Ｒ４ｂとすると、以
下の式を満たすのが更に好ましい。In particular, when the fourth lens group is composed of a single lens (or one block such as bonding), it is preferable that this lens is a biconcave lens. If the radii of curvature on the object side and the radius of curvature on the image plane side are R4a and R4b, respectively, it is more preferable to satisfy the following equation.
【００５６】 ｜Ｒ４ａ｜／Ｒ４ｂ＞１．１ ‥‥‥（１２） この様に構成すると第４レンズ群の第２主点位置が第５
レンズ群側に移り、第４レンズ群の可動範囲を大きく取
れるので有効である。| R4a | / R4b> 1.1 (12) With this structure, the second principal point position of the fourth lens group is the fifth position.
This is effective because it can be moved to the lens group side and the movable range of the fourth lens group can be widened.
【００５７】特に、収差の発生を小さくして可動範囲を
多く取るには更に以下の範囲にあるのが好ましい。In particular, in order to reduce the occurrence of aberration and increase the movable range, the following range is preferable.
【００５８】 １．４＜｜Ｒ４ａ｜／Ｒ４ｂ＜３．０ ‥‥‥（１２ａ） （１−１２）全系の焦点距離に対して、最後の結像レン
ズである第５レンズ群を良好な収差にして、またバック
フォーカスを適当に確保するために以下の条件式を満た
しているのが好ましい。1.4 <| R4a | / R4b <3.0 (12a) (1-12) With respect to the focal length of the entire system, the fifth lens group, which is the last image forming lens, is favorably set. It is preferable that the following conditional expressions are satisfied in order to obtain aberration and to properly secure the back focus.
【００５９】 １．５０＜Ｆ５／Ｆｗ＜２．５０ ‥‥‥（１３） 上限値を越えるとバックフォーカスが長くなり大型化す
るため適当でない。また下限値を越えると第５レンズ群
の屈折力が強くなり特に球面収差やコマ収差が特に中間
ズーム域で発生し適当でない。またテレセントリックな
関係が崩れ、射出瞳が短くなり適当でない。またフィル
ター等のブロックを入れるのが無理になり、好ましくな
い。1.50 <F5 / Fw <2.50 (13) If the value exceeds the upper limit, the back focus becomes long and the size becomes large, which is not suitable. On the other hand, if the value goes below the lower limit, the refracting power of the fifth lens group becomes strong, and spherical aberration and coma especially occur in the intermediate zoom range, which is not suitable. In addition, the telecentric relationship is broken and the exit pupil is shortened, which is not appropriate. In addition, it is not possible to insert a block such as a filter, which is not preferable.
【００６０】本発明の構成では、ズームレンズの射出瞳
位置を短くなりすぎないように設定し、更に上述した様
に物体側からの斜光束が瞳に浅い角度で入射させ、前玉
径の小型化に寄与している。In the configuration of the present invention, the exit pupil position of the zoom lens is set so as not to be too short, and the oblique light flux from the object side is incident on the pupil at a shallow angle as described above, and the front lens diameter is small. Contribute to
【００６１】上述した絞りから像面側のレンズ群のパワ
ー設定範囲を上限値を越えて設定すると、上記斜光束が
浅い角度に設定できずに前玉径の増大を招き、また下限
値を越えると射出瞳がプラス側に短くなりすぎ、固体撮
像素子に対してテレセントリックな光束を確保できず、
またズーム、フォーカスに対して収差変動が大きくなり
適当ではない。When the power setting range of the lens group on the image side from the diaphragm is set to exceed the upper limit value, the oblique light beam cannot be set to a shallow angle, which causes an increase in the front lens diameter and exceeds the lower limit value. And the exit pupil becomes too short on the plus side, and a telecentric luminous flux cannot be secured for the solid-state image sensor,
In addition, the aberration variation is large with respect to zooming and focusing, which is not suitable.
【００６２】以上の範囲に入っていれば距離合わせ（フ
ォーカシング）に対しても大きな移動にならないように
小型化を達成するものである。このように範囲を逸脱す
ると前玉径が大型化し全系も大型化して、更に撮像素子
に対して適当な射出角度を設定できなくなる。Within the above range, miniaturization is achieved so as not to make a great movement even for distance matching (focusing). If the diameter deviates from the range as described above, the diameter of the front lens becomes large and the entire system also becomes large, and it becomes impossible to set an appropriate emission angle for the image pickup device.
【００６３】特に射出瞳位置に関しては以下の条件も満
足しているのが好ましい。In particular, it is preferable that the following conditions are satisfied with respect to the exit pupil position.
【００６４】 −１．２＜Ｆ４／Ｆ５＜−０．８０ ‥‥‥（１４） この式の上限値を越えると第４レンズ群の屈折力が強く
なりフォーカシングの距離変動が大きくなり適当でな
い。また下限値を越えるとフォーカシングの移動量が大
きくなり大型化して適当でないばかりでなく固定の結像
レンズである第５レンズ群の屈折力が強くなり射出瞳が
短くなり適当でない。-1.2 <F4 / F5 <-0.80 (14) If the upper limit of this expression is exceeded, the refractive power of the fourth lens group becomes too strong and the distance variation of focusing becomes large, which is not appropriate. On the other hand, if the value goes below the lower limit, the moving amount of focusing becomes large and the size becomes large, which is not suitable, and also the fifth lens group, which is a fixed imaging lens, has a strong refractive power and the exit pupil becomes short, which is not suitable.
【００６５】（１−１３）光学系の射出瞳を適当に設定
しつつ、レンズのバックフォーカスを適正に確保するた
めには、第５群の結像倍率をβ５としたとき、以下の条
件を満たしているのが好ましい。(1-13) In order to properly secure the back focus of the lens while appropriately setting the exit pupil of the optical system, the following conditions are set when the image forming magnification of the fifth group is β5. It is preferable to satisfy.
【００６６】｜β５｜＜０．２５ ‥‥‥（１５） この式を逸脱すると、バックフォーカスが大きくなりレ
ンズ系が大きくなるばかりでなく射出瞳が短くなり適当
でない。| Β5 | <0.25 (15) If this equation is not satisfied, not only the back focus becomes large and the lens system becomes large, but also the exit pupil becomes short, which is not appropriate.
【００６７】（１−１４）全系の焦点距離に対して、最
後の結像レンズである第５レンズ群を良好な収差にし
て、またバックフォーカスを適当に確保するために以下
の条件式を満たしているのが好ましい。(1-14) With respect to the focal length of the entire system, the following conditional expression is used in order to make the fifth lens group, which is the last image forming lens, have a good aberration and to properly secure the back focus. It is preferable to satisfy.
【００６８】[0068]
【数１】 上限値を越えるとバックフォーカスが長くなり大型化す
るため適当でない。また下限値を越えると第５レンズ群
の屈折力が強くなり特に球面収差やコマ収差が特に中間
ズーム域で発生し適当でない。またテレセントリックな
関係が崩れ、射出瞳が短くなり適当でない。[Equation 1] If the value exceeds the upper limit, the back focus becomes long and the size becomes large, which is not suitable. On the other hand, if the value goes below the lower limit, the refracting power of the fifth lens group becomes strong, and spherical aberration and coma especially occur in the intermediate zoom range, which is not suitable. In addition, the telecentric relationship is broken and the exit pupil is shortened, which is not appropriate.
【００６９】（１−１５）適当なバックフォーカスを保
持しつつ、固体撮像素子に対する射出瞳位置を変動を小
さく設定するには、第４レンズ群の結像倍率β４がズー
ミングに伴い常に同一符号であることが好ましい。結像
倍率β４がズーミング中、符号を変えて変化すると、最
終結像レンズ群である固定の第５レンズ群への入射角度
の変化が大きく、ズーミングに伴い、特に周辺光束の固
体撮像素子（ＣＣＤ等）へ入射角度の変動が大きく、テ
レセントリックな結像からのズレが大きくなりシェーデ
ィング発生の原因になり適当でない。(1-15) In order to set the exit pupil position with respect to the solid-state image pickup device with a small variation while maintaining an appropriate back focus, the imaging magnification β4 of the fourth lens group is always set to the same sign as zooming. Preferably there is. When the imaging magnification β4 changes while changing the sign during zooming, the incident angle on the fixed fifth lens group, which is the final imaging lens group, changes greatly. Etc.), the fluctuation of the incident angle is large and the deviation from the telecentric image formation becomes large, which causes shading, which is not suitable.
【００７０】更に、特に射出瞳がプラス側で短くなる広
角端、望遠端でのシェーディングを小さくし、適当なバ
ックフォーカスを保持するには以下の式を満足するのが
好ましい。Further, in order to reduce the shading at the wide-angle end and the telephoto end where the exit pupil becomes shorter on the plus side, and to maintain an appropriate back focus, it is preferable to satisfy the following formula.
【００７１】β４Ｗ×β４Ｔ＞０ ‥‥‥（１７） ここで、広角端及び望遠端の物体距離無限遠での第４レ
ンズ群の近軸横倍率をそれぞれβ４Ｗ，β４Ｔとする。Β4W × β4T> 0 (17) Here, the paraxial lateral magnifications of the fourth lens group at the wide-angle end and the telephoto end at the object distance of infinity are β4W and β4T, respectively.
【００７２】（１−１６）全系を小型化にするときは、
以下の条件を満たすのが好ましい。(1-16) When downsizing the entire system,
It is preferable to satisfy the following conditions.
【００７３】 １．５＜Ｂｆｗ／Ｆｗ＜２．２ ‥‥‥（１８） ここで、Ｂｆｗは広角端での物体距離無限遠時のバック
フォーカス（ガラスブロック、フィルター等実施例中の
“Ｇ”を除く）である。この式は全系を効果的に小型化
するのに必要な式であり、下限値を越えるとフィルター
等のブロックを入れるのが無理になるばかりでなく、射
出瞳が短めとなり、撮像素子への結像がテレセントリッ
ク系からズレることになり不適当である。また上限値を
越えると大型化して不適当である。1.5 <Bfw / Fw <2.2 (18) where Bfw is the back focus at the wide-angle end when the object distance is infinity (glass block, filter, etc., “G” in the examples). Except). This formula is necessary to effectively downsize the entire system. If the lower limit is exceeded, it will not be possible to insert a block such as a filter, and the exit pupil will be shortened. The image formation is unsuitable because it deviates from the telecentric system. On the other hand, if it exceeds the upper limit, the size becomes large and it is not suitable.
【００７４】（１−１７）第１レンズ群は少なくとも１
枚の負レンズを含む複数のレンズで構成され、第２レン
ズ群は少なくとも１枚の正レンズを含む複数のレンズで
構成され、第３レンズ群は１枚の正レンズで構成され、
第４レンズ群は少なくとも１枚の負レンズで構成され、
第５レンズ群は少なくとも１枚の負レンズを含む複数の
レンズで構成されているのが好ましい。(1-17) At least 1 is the first lens group
The second lens group includes a plurality of lenses including at least one positive lens, and the third lens group includes a single positive lens.
The fourth lens group includes at least one negative lens,
The fifth lens group preferably comprises a plurality of lenses including at least one negative lens.
【００７５】特に第１レンズ群は、物体側より順に、物
体側に凸面を有する負メニスカスレンズ、物体側に凸面
を有する正レンズ、物体側に凸面を有する正レンズの３
枚で構成され、第２レンズ群は、物体側より順に、物体
側に凸面を有する負メニスカスレンズ、両凹レンズ、正
レンズの順で構成されているのが良い。In particular, the first lens group includes, in order from the object side, a negative meniscus lens having a convex surface on the object side, a positive lens having a convex surface on the object side, and a positive lens having a convex surface on the object side.
It is preferable that the second lens group is composed of a single lens element, and in order from the object side, a negative meniscus lens having a convex surface on the object side, a biconcave lens, and a positive lens.
【００７６】第３レンズ群のいずれかのレンズ面に非球
面を持っていても良い。非球面は物体側、像面側いずれ
に配しても良い。特に非球面は、球面収差の補正のため
には物体側に施した方が比較的良好である。Any lens surface of the third lens group may have an aspherical surface. The aspherical surface may be arranged on either the object side or the image plane side. In particular, the aspherical surface is relatively good on the object side in order to correct spherical aberration.
【００７７】又第４レンズ群はズーミング中の第２レン
ズ群の若しくは第２レンズ群の移動に伴う像点変動を補
正すると共に、フォーカシングを行う様に移動する。特
にフォーカシングに伴う収差変動、特に色収差変動を押
さえるため単レンズではなく、正レンズと負レンズの２
枚で構成しても良い。特にこの際正レンズと負レンズは
貼合せにして１ブロック化しても良い。またこのとき正
レンズと負レンズのアッベ数をそれぞれν４ｐ，ν４ｎ
とすると ν４ｐ＜ν４ｎ を満たしているのが好ましい。この範囲を逸脱すると色
収差の距離変動が大きくなり適当ではない。The fourth lens unit corrects the image point variation due to the movement of the second lens unit or the second lens unit during zooming, and moves so as to perform focusing. In particular, in order to suppress fluctuations in aberrations due to focusing, especially fluctuations in chromatic aberration, two lenses, a positive lens and a negative lens, are used instead of a single lens.
It may be composed of one sheet. In this case, in particular, the positive lens and the negative lens may be attached to each other to form one block. At this time, the Abbe numbers of the positive lens and the negative lens are respectively ν4p and ν4n
Then, it is preferable that ν4p <ν4n is satisfied. If it deviates from this range, the variation of chromatic aberration in distance becomes large, which is not suitable.
【００７８】このように第４レンズ群を正レンズと負レ
ンズの２枚を貼合せにするとズーミングとフォーカシン
グで共に移動する第４レンズ群の構成が１ブロックとな
り上述した単レンズで構成する物となんら変わりがなく
簡易化し保持し易くなる。As described above, when the positive lens and the negative lens of the fourth lens group are cemented together, the configuration of the fourth lens group that moves together during zooming and focusing becomes one block, and the fourth lens group is composed of the above-mentioned single lens. There is no change and it becomes simple and easy to hold.
【００７９】更に、第４レンズ群を構成する正レンズ、
負レンズのアッベ数を、ν４ｐ，ν４ｎとするとき、以
下の式を満足するのが好ましい。Further, a positive lens which constitutes the fourth lens group,
When the Abbe numbers of the negative lens are ν4p and ν4n, it is preferable to satisfy the following formula.
【００８０】ν４ｎ−ν４ｐ＞１５ 更に、ズーミング中の色収差の変動を有効に行うために
は、以下の式を満たしている方が良い。Ν4n-ν4p> 15 Furthermore, in order to effectively change the chromatic aberration during zooming, it is better to satisfy the following formula.
【００８１】ν４ｎ−ν４ｐ＞３０ 第４レンズ群を構成するレンズが上述したように１ブロ
ック化した場合、特に正レンズと負レンズの貼合せや負
レンズ１枚で構成された場合、そのブロックの物体側面
は物体側に凹を向け、像側面は像側に凹面をむけている
のが好ましい。Ν4n-ν4p> 30 When the lenses constituting the fourth lens group are made into one block as described above, particularly when the positive lens and the negative lens are cemented together or when the negative lens is constituted by one negative lens, It is preferable that the object side surface is concave toward the object side, and the image side surface is concave toward the image side.
【００８２】第５レンズ群はズーミング中固定の正レン
ズ群であり、球面収差が発生し易い。この球面収差を補
正するには、少なくとも１枚の正レンズと少なくとも１
枚の負レンズで構成するのが好ましい。特に第５レンズ
群に正レンズを１枚、負レンズを１枚の２枚で構成する
ときはいずれかのレンズ面に非球面を配するのが良い。
これにより良好に球面収差を補正できる。特に色収差の
補正を行うために貼合せレンズを配しても良い。The fifth lens group is a positive lens group which is fixed during zooming, and spherical aberration easily occurs. To correct this spherical aberration, at least one positive lens and at least one
It is preferably composed of a single negative lens. In particular, when the fifth lens group is composed of one positive lens and one negative lens, it is preferable to dispose an aspherical surface on either lens surface.
Thereby, spherical aberration can be corrected well. In particular, a cemented lens may be provided to correct chromatic aberration.
【００８３】また、第５レンズ群に正レンズを１枚、負
レンズを１枚の２枚で構成するときは、物体側から順に
物体側に凸面を向けた負のメニスカスレンズ、両凸レン
ズの順に構成したほうがよい。こうすることにより第２
主点位置が像面側になり、バックフォーカスの確保に有
効である。またこの時２つのレンズは梁合わせてブロッ
ク化しても良い。こうするとレンズ群の保持が容易とな
り簡易構成化が可能となる。When the fifth lens group is composed of two positive lenses and one negative lens, a negative meniscus lens having a convex surface facing the object side and a biconvex lens in this order from the object side. Better configure it. By doing this, the second
The principal point position is on the image plane side, which is effective for securing the back focus. At this time, the two lenses may be combined into a block by combining the beams. This makes it easy to hold the lens group and allows a simple configuration.
【００８４】（１−１８）広角化の為に第１レンズ群と
第２レンズ群の主点間隔ｅ１を広角端でいかに小さくで
きるかは重要な点のひとつである。そのためには特に第
２レンズ群の形状は具体的には以下のような構成が好ま
しい。(1-18) How to reduce the principal point distance e1 between the first lens group and the second lens group at the wide-angle end for widening the angle is an important point. For that purpose, the shape of the second lens group is specifically preferably the following configuration.
【００８５】主点間隔ｅ１を広角端で短くする為に、第
２レンズ群の物体側（第１）主点を物体側に設定するよ
うな構成にすることが、広角化には望ましい。具体的に
は、第２レンズ群の物体側より順に、物体側に凸面を有
する負メニスカスレンズＬ２１、両凹の負レンズＬ２
１、空気間隔を挟んで正レンズＬ２３の順に配置するこ
とである。この空気間隔によって第２レンズ群の物体側
主点が第１レンズ寄りになり、広角側における主点間隔
ｅ１を短く取りやすくなり広角化に有効である。また更
に正レンズＬ２３の像面側に負レンズＬ２４を配しても
良い。この負レンズＬ２４により更に第２レンズ群の物
体側主点が第１レンズ寄りになり、またズーミングによ
る色収差の変動も押さえられるので有効である。In order to shorten the principal point interval e1 at the wide angle end, it is desirable to set the object side (first) principal point of the second lens group to the object side for widening the angle. Specifically, in order from the object side of the second lens unit, a negative meniscus lens L21 having a convex surface on the object side and a biconcave negative lens L2.
First, the positive lens L23 is arranged in this order with the air gap therebetween. This air gap makes the object-side principal point of the second lens group closer to the first lens, which makes it easier to shorten the principal point spacing e1 on the wide-angle side, which is effective for widening the angle. Further, a negative lens L24 may be arranged on the image plane side of the positive lens L23. This negative lens L24 is effective because the object-side principal point of the second lens unit is further closer to the first lens, and fluctuations in chromatic aberration due to zooming are suppressed.
【００８６】（１−１９）小型で広角のズームレンズの
達成は、最も物体側のレンズの外径をφ１、広角端の全
系の焦点距離をＦｗとするとき、以下の条件式を満足す
ることで可能である。(1-19) To achieve a compact and wide-angle zoom lens, the following conditional expression is satisfied, where φ1 is the outer diameter of the lens closest to the object and Fw is the focal length of the entire system at the wide-angle end. This is possible.
【００８７】 ０．１０＜Ｆｗ／φ１＜０．２０ ‥‥‥（１９） 一般に広角端の焦点距離Ｆｗが短くなると、前玉径φ１
は大きくなる。逆に広角端の焦点距離Ｆｗが長めになる
と、レンズの望遠端の明るさにも寄るが前玉径φ１小さ
くなる。（１９）式は、小型で広角のズームレンズを達
成するための前玉径と広角端の焦点距離の適切なバラン
スを提示したものである。この式の上限・下限どちらを
逸脱しても小型で広角のズームレンズの提供はできなく
なる。具体的には、上限を逸脱すると望遠寄りのズーム
レンズになり、下限を逸脱すると大型のズームレンズに
なりがちとなる。0.10 <Fw / φ1 <0.20 (19) Generally, when the focal length Fw at the wide-angle end becomes short, the front lens diameter φ1
Grows. On the contrary, when the focal length Fw at the wide-angle end becomes longer, the front lens diameter φ1 becomes smaller depending on the brightness at the telephoto end of the lens. Expression (19) presents an appropriate balance between the front lens diameter and the focal length at the wide-angle end to achieve a compact and wide-angle zoom lens. If either the upper limit or the lower limit of this formula is deviated, it becomes impossible to provide a compact and wide-angle zoom lens. Specifically, if the upper limit is exceeded, the zoom lens will be closer to the telephoto side, and if the lower limit is exceeded, the zoom lens will be a large zoom lens.
【００８８】ここで論じている前玉径φ１とは、第１レ
ンズの光学有効径に準ずるもので、実際のレンズ外径の
ことである。前玉径φ１は、第１レンズの光学有効径よ
り０〜６％程度大きいものを示す。The front lens diameter φ1 discussed here corresponds to the optically effective diameter of the first lens and is the actual lens outer diameter. The front lens diameter φ1 indicates a diameter which is about 0 to 6% larger than the optically effective diameter of the first lens.
【００８９】次に本発明の数値実施例を示す。数値実施
例においてＲｉは物体側より順に第ｉ番目のレンズ面の
曲率半径、Ｄｉは物体側より第ｉ番目のレンズ厚及び空
気間隔、Ｎｉとνｉは各々物体側より順に第ｉ番目のレ
ンズのガラスの屈折率とアッベ数である。Next, numerical examples of the present invention will be shown. In the numerical examples, Ri is the radius of curvature of the i-th lens surface in order from the object side, Di is the i-th lens thickness and air gap from the object side, and Ni and νi are respectively from the object side of the i-th lens. The refractive index of glass and the Abbe number.
【００９０】尚、数値実施例において最後から２つのレ
ンズ面はフェースプレート等のガラス材である。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。非球面形状は光軸方向にＸ軸、光軸と垂直方
向にＨ軸、光の進行方向を正とし、Ｒを近軸曲率半径、
Ｋ，Ａ，Ｂ，Ｃ，Ｄ，Ｅを各々非球面係数としたときIn the numerical examples, the last two lens surfaces are glass materials such as face plates. Also, the relationship between each of the above-mentioned conditional expressions and various numerical values in the numerical examples is shown in Table-
It is shown in FIG. The aspherical shape has an X axis in the optical axis direction, an H axis in the direction perpendicular to the optical axis, a light traveling direction is positive, and R is a paraxial radius of curvature,
When K, A, B, C, D and E are aspherical coefficients respectively
【００９１】[0091]
【数２】 なる式で表している。又「ｅ−０Ｘ」は「１０−X」を
意味している。[Equation 2] It is expressed by the formula. Also, "e-0X" means "10- X ".
【００９２】[0092]
【外１】 [Outside 1]
【００９３】[0093]
【外２】 [Outside 2]
【００９４】[0094]
【外３】 [Outside 3]
【００９５】[0095]
【外４】 [Outside 4]
【００９６】[0096]
【外５】 [Outside 5]
【００９７】[0097]
【外６】 [Outside 6]
【００９８】[0098]
【表１】 [Table 1]
【００９９】[0099]
【発明の効果】本発明によれば以上のように、リヤーフ
ォーカス方式を採用しつつ、大口径比化、広画角化及び
変倍比６程度の高変倍化、そして前玉径の縮少化を図
り、レンズ系全体の小型化を図りつつ、広角端から望遠
端に至る全変倍範囲にわたり、又無限遠物体から近距離
物体に至る物体距離全般にわたり、良好なる光学性能を
有した、特に広角端における歪曲収差を良好に補正した
簡易な構成のリヤーフォーカス式のズームレンズを達成
することができる。As described above, according to the present invention, while adopting the rear focus system, a large aperture ratio, a wide angle of view, a high zoom ratio of about 6 and a reduction of the front lens diameter are adopted. The optical system has good optical performance over the entire zoom range from the wide-angle end to the telephoto end, and over the entire object distance from infinity objects to short-distance objects, while aiming to reduce the size and overall size of the lens system. In particular, it is possible to achieve a rear-focus type zoom lens having a simple configuration in which distortion aberration is satisfactorily corrected at the wide-angle end.
【図１】本発明に係るリヤーフォーカス式のズームレン
ズの近軸屈折力配置の説明図FIG. 1 is an explanatory view of a paraxial refractive power arrangement of a rear focus type zoom lens according to the present invention.
【図２】本発明の数値実施例１のレンズ断面図FIG. 2 is a lens cross-sectional view of Numerical Example 1 of the present invention.
【図３】本発明の数値実施例２のレンズ断面図FIG. 3 is a lens cross-sectional view of Numerical Example 2 of the present invention.
【図４】本発明の数値実施例３のレンズ断面図FIG. 4 is a lens cross-sectional view of Numerical Example 3 of the present invention.
【図５】本発明の数値実施例４のレンズ断面図FIG. 5 is a lens cross-sectional view of Numerical Example 4 of the present invention.
【図６】本発明の数値実施例５のレンズ断面図FIG. 6 is a lens cross-sectional view of Numerical Example 5 of the present invention.
【図７】本発明の数値実施例６のレンズ断面図FIG. 7 is a lens cross-sectional view of Numerical Example 6 of the present invention.
【図８】本発明の数値実施例１の広角端の収差図FIG. 8 is an aberration diagram at the wide-angle end according to Numerical Example 1 of the present invention.
【図９】本発明の数値実施例１の望遠端の収差図FIG. 9 is an aberration diagram at a telephoto end according to Numerical Example 1 of the present invention.
【図１０】本発明の数値実施例２の広角端の収差図FIG. 10 is an aberration diagram at a wide-angle end according to Numerical Example 2 of the present invention.
【図１１】本発明の数値実施例２２の望遠端の収差図FIG. 11 is an aberration diagram at a telephoto end according to Numerical Example 22 of the present invention.
【図１２】本発明の数値実施例３の広角端の収差図FIG. 12 is an aberration diagram at a wide-angle end according to Numerical Example 3 of the present invention.
【図１３】本発明の数値実施例３の望遠端の収差図FIG. 13 is an aberration diagram at a telephoto end according to Numerical Example 3 of the present invention.
【図１４】本発明の数値実施例４の広角端の収差図FIG. 14 is an aberration diagram at the wide-angle end according to Numerical Example 4 of the present invention.
【図１５】本発明の数値実施例４の望遠端の収差図FIG. 15 is an aberration diagram at a telephoto end according to Numerical Example 4 of the present invention.
【図１６】本発明の数値実施例５の広角端の収差図FIG. 16 is an aberration diagram at a wide-angle end according to Numerical Example 5 of the present invention.
【図１７】本発明の数値実施例５の望遠端の収差図FIG. 17 is an aberration diagram at a telephoto end according to Numerical Example 5 of the present invention.
【図１８】本発明の数値実施例６の広角端の収差図FIG. 18 is an aberration diagram at a wide-angle end according to Numerical Example 6 of the present invention.
【図１９】本発明の数値実施例６の望遠端の収差図FIG. 19 is an aberration diagram at a telephoto end according to Numerical Example 6 of the present invention.
Ｌ１ 第１群 Ｌ２ 第２群 Ｌ３ 第３群 Ｌ４ 第４群 Ｌ５ 第５群 ＳＰ 絞り ＩＰ 像面 ｄ ｄ線 ｇ ｇ線 ΔＳ サジタル像面 ΔＭ メリディオナル像面 L1 1st group L2 2nd group L3 3rd group L4 4th group L5 5th group SP Aperture IP image plane d d line g g line ΔS sagittal image plane ΔM meridional image plane
Claims (3)
の屈折力の第２群、正の屈折力の第３群、負の屈折力の
第４群、そして正の屈折力の第５群の５つのレンズ群を
有し、該第２群を像面側へ移動させて広角端から望遠端
への変倍を行い、変倍に伴う像面変動を該第４群を移動
させて補正すると共に該第４群を光軸上移動させてフォ
ーカスを行い、該第３群を正の単一レンズより構成した
ことを特徴とするリヤーフォーカス式のズームレンズ。1. A first group having a positive refractive power, a second group having a negative refractive power, a third group having a positive refractive power, a fourth group having a negative refractive power, and a positive refractive power in order from the object side. Of the fifth lens group, the second lens group is moved to the image plane side to perform zooming from the wide-angle end to the telephoto end, and the image plane variation caused by zooming is changed to the fourth group. A rear focus type zoom lens, characterized in that the fourth lens unit is moved and corrected and the fourth lens unit is moved on the optical axis for focusing, and the third lens unit is composed of a single positive lens.
第４群は像面側に凸状の軌跡を有して移動していること
を特徴とする請求項１のリヤーフォーカス式のズームレ
ンズ。2. The rear-focus type zoom lens according to claim 1, wherein the fourth lens unit has a convex locus on the image plane side when zooming from the wide-angle end to the telephoto end. lens.
おける全系の焦点距離をＦｗとしたとき ４＜Ｆ１／Ｆｗ＜６．５ なる条件を満足することを特徴とする請求項１のリヤー
フォーカス式のズームレンズ。3. When the focal length of the first lens unit is F1 and the focal length of the entire system at the wide angle end is Fw, the condition 4 <F1 / Fw <6.5 is satisfied. Rear focus type zoom lens.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP30701494A JP3161258B2 (en) | 1994-11-15 | 1994-11-15 | Rear focus zoom lens |
| US08/485,136 US5847882A (en) | 1994-06-23 | 1995-06-07 | Rear focusing zoom lens |
| US09/121,093 US6094312A (en) | 1994-06-23 | 1998-07-23 | Rear focusing zoom lens |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP30701494A JP3161258B2 (en) | 1994-11-15 | 1994-11-15 | Rear focus zoom lens |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH08146295A true JPH08146295A (en) | 1996-06-07 |
| JP3161258B2 JP3161258B2 (en) | 2001-04-25 |
Family
ID=17963989
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP30701494A Expired - Fee Related JP3161258B2 (en) | 1994-06-23 | 1994-11-15 | Rear focus zoom lens |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3161258B2 (en) |
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|---|---|---|---|---|
| JPH095624A (en) * | 1995-06-19 | 1997-01-10 | Fuji Photo Optical Co Ltd | Zoom lens |
| JP2001124992A (en) * | 1999-10-29 | 2001-05-11 | Canon Inc | Variable power optical system having vibration-proof function, and optical equipment equipped with the same |
| US6987622B2 (en) | 2003-11-06 | 2006-01-17 | Canon Kabushiki Kaisha | Zoom lens and image taking system |
| US7187504B2 (en) | 2005-06-02 | 2007-03-06 | Canon Kabushiki Kaisha | Zoom lens and image pick up apparatus including the same |
| JP2008304708A (en) * | 2007-06-07 | 2008-12-18 | Konica Minolta Opto Inc | Zoom lens and imaging apparatus |
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| WO2010098407A1 (en) * | 2009-02-26 | 2010-09-02 | 株式会社タムロン | Zoom lens |
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-
1994
- 1994-11-15 JP JP30701494A patent/JP3161258B2/en not_active Expired - Fee Related
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|---|---|---|---|---|
| JPH095624A (en) * | 1995-06-19 | 1997-01-10 | Fuji Photo Optical Co Ltd | Zoom lens |
| JP2001124992A (en) * | 1999-10-29 | 2001-05-11 | Canon Inc | Variable power optical system having vibration-proof function, and optical equipment equipped with the same |
| US6987622B2 (en) | 2003-11-06 | 2006-01-17 | Canon Kabushiki Kaisha | Zoom lens and image taking system |
| US7187504B2 (en) | 2005-06-02 | 2007-03-06 | Canon Kabushiki Kaisha | Zoom lens and image pick up apparatus including the same |
| JP2008304708A (en) * | 2007-06-07 | 2008-12-18 | Konica Minolta Opto Inc | Zoom lens and imaging apparatus |
| US7903344B2 (en) | 2007-10-01 | 2011-03-08 | Nikon Corporation | Zoom lens, optical apparatus equipped with the zoom lens and method for forming an image of an object and varying a focal length |
| EP2048533A1 (en) * | 2007-10-01 | 2009-04-15 | Nikon Corporation | Zoom lens, optical apparatus equipped with the zoom lens and method for forming an image of an object and varying a focal length |
| WO2010098407A1 (en) * | 2009-02-26 | 2010-09-02 | 株式会社タムロン | Zoom lens |
| CN102334059A (en) * | 2009-02-26 | 2012-01-25 | 株式会社腾龙 | Zoom lens |
| JPWO2010098407A1 (en) * | 2009-02-26 | 2012-09-06 | 株式会社タムロン | Zoom lens |
| JP5426653B2 (en) * | 2009-02-26 | 2014-02-26 | 株式会社タムロン | Zoom lens |
| US8614855B2 (en) | 2009-02-26 | 2013-12-24 | Tamron Co., Ltd. | Zoom lens |
| JP2011175098A (en) * | 2010-02-24 | 2011-09-08 | Nikon Corp | Zoom lens system, optical apparatus and method for manufacturing zoom lens system |
| US8605362B2 (en) | 2010-02-24 | 2013-12-10 | Nikon Corporation | Zoom lens system, optical apparatus and method for manufacturing zoom lens system |
| US20130148005A1 (en) * | 2010-08-24 | 2013-06-13 | Panasonic Corporation | Zoom lens system, interchangeable lens apparatus and camera system |
| US8934177B2 (en) * | 2010-08-24 | 2015-01-13 | Panasonic Intellectual Property Managment Co., Ltd | Zoom lens system, interchangeable lens apparatus and camera system |
| JP2012226309A (en) * | 2011-04-07 | 2012-11-15 | Panasonic Corp | Inner focus lens, interchangeable lens device, and camera system |
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| JP2014006355A (en) * | 2012-06-22 | 2014-01-16 | Tamron Co Ltd | Zoom lens and imaging apparatus including the same |
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