JPH0829685A - Inner focus type zoom lens - Google Patents

Abstract

PURPOSE:To reduce the overall size of the lens system while increasing the power variation rate by providing a 1st and a 2nd lens group in order from the object side and putting the lens system in focus through a lens group which is part of the 2nd group. CONSTITUTION:This zoom lens has the 1st lens group L1 which has negative refracting power, the 2nd lens group L2 which has positive refracting power, a 3rd lens group L3 which has negative refracting power, and a 4th lens group L4 which has positive refracting power. The 2nd group L2 has a 21st lens group L21 with positive refracting power and a 22nd lens group L22 with positive refracting power. For power variation from the wide-angle end to the telephoto end, the 1st group L1 is moved having a track which is convex to the image plane side to vary the power, and image plane variation is corrected. The zoom lens is put in focus on a short-distance body from an infinite-distance body by moving the 21st lens group L21 of the 2nd group L2 toward the image plane IP. Consequently, the respective lens groups L21 and L22 need not be made large in refracting power and the number of the lens elements of the 2nd group L2 can be decreased.

Description

【発明の詳細な説明】Detailed Description of the Invention

【０００１】[0001]

【産業上の利用分野】本発明は３５ｍｍフィルム用の写
真カメラや電子記録方式のビデオカメラ、そしてＳＶカ
メラ等に好適なインナーフォーカス式のズームレンズに
関し、特に負の屈折力のレンズ群が先行する複数のレン
ズ群を有し、第２群の一部のレンズ群でフォーカスを行
った物体距離全般にわたり高い光学性能を有した焦点距
離３８〜１０５ｍｍ（３５ｍｍフィルム換算）程度のも
のである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inner focus type zoom lens suitable for a photographic camera for 35 mm film, an electronic recording type video camera, an SV camera and the like, and particularly, a lens group having a negative refractive power precedes it. It has a plurality of lens groups and has a focal length of 38 to 105 mm (35 mm film equivalent), which has high optical performance over the entire object distance focused by a part of the second lens group.

【０００２】[0002]

【従来の技術】従来より写真用カメラやビデオカメラ等
のズームレンズにおいては物体側の第１群以外のレンズ
群を移動させてフォーカスを行う、所謂インナーフォー
カス式を採用したものが種々と提案されている。2. Description of the Related Art Conventionally, various zoom lenses for photographic cameras, video cameras, etc. have been proposed which employ a so-called inner focus type in which focusing is performed by moving a lens unit other than the first lens unit on the object side. ing.

【０００３】一般にインナ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、自
動焦点検出装置を有したカメラには迅速な焦点合わせが
できる等の特徴がある。又防水用カメラには防水の為の
構成が簡素化される等の特徴がある。In general, an inner focus type zoom lens has a smaller effective diameter of the first lens group as compared with a zoom lens in which the first lens group is moved for focusing, which facilitates downsizing of the entire lens system and close-up photography. , Especially in close-up shooting, because the lens group that is relatively small and lightweight is moved, the driving force of the lens group is small, and quick focusing is possible for a camera with an automatic focus detection device. There are features such as being able to. In addition, the waterproof camera has features such as a simplified structure for waterproofing.

【０００４】インナーフォーカス式のズームレンズとし
て例えば特開昭５８−１７８３１７号公報では物体側か
ら数えて２番目の第２群の一部分でフォーカスを行った
インナーフォーカス式のズームレンズを提案している。
同公報では第２群を正と負の屈折力の２つのレンズ群、
又は負，正，そして負の屈折力の３つのレンズ群に分割
し、そのうちの一部のレンズ群でフォーカスを行ってい
る。As an inner focus type zoom lens, for example, Japanese Patent Application Laid-Open No. 58-178317 proposes an inner focus type zoom lens in which focusing is performed by a part of the second group which is second from the object side.
In this publication, the second group is defined as two lens groups having positive and negative refractive powers,
Alternatively, the lens is divided into three lens groups having negative, positive, and negative refracting powers, and focusing is performed by a part of the lens groups.

【０００５】[0005]

【発明が解決しようとする課題】一般にズームレンズに
おいてインナ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る。Generally, when an inner focus system is adopted in a zoom lens, the entire lens system is downsized and quick focusing becomes possible.

【０００６】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ってくるという問題
点が生じてくる。On the other hand, on the other hand, the fluctuation of aberration at the time of 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. The problem arises.

【０００７】先の特開昭５８−１７８３１７号公報で提
案しているインナーフォーカス式のズームレンズでは第
２群を逆符号の屈折力を有する複数のレンズ群に分割し
ている為に第２群中の各レンズ群の屈折力が強くなり、
この結果、第２群全体のレンズ枚数が増加し、又フォー
カスの際の収差変動が大きくなる傾向があった。In the inner focus type zoom lens proposed in Japanese Patent Laid-Open No. 58-178317, the second group is divided into a plurality of lens groups having refractive powers of opposite signs, so that the second group is divided. The refractive power of each lens group inside becomes stronger,
As a result, the number of lenses in the second lens group as a whole tends to increase, and the aberration variation during focusing tends to increase.

【０００８】本発明は、第２群の一部のレンズ群でフォ
ーカスを行うインナーフォーカス方式を採用しつつ、高
変倍化を図ると共に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自動焦点検出装置を有したカメラ
や防水用カメラ等に好適なインナ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 an inner focus system in which a part of the second lens group is used for focusing, the zoom ratio is increased and the overall size of the lens system is reduced.
Suitable for cameras, waterproof cameras, etc. that have an automatic focus detection device with 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 The objective is to provide a simple inner focus type zoom lens.

【０００９】[0009]

【課題を解決するための手段】本発明のインナーフォー
カス式のズームレンズは、 （１−１）物体側より順に第１群，第２群のレンズ群が
存在し、変倍時該第１群と第２群は独立して光軸方向に
動き、該第２群は同一の符号の屈折力の第２１レンズ群
と第２２レンズ群の２つのレンズ群を有し、該第２１レ
ンズ群又は第２２レンズ群でフォーカスしていることを
特徴としている。The inner focus type zoom lens of the present invention comprises (1-1) a first group and a second group of lens groups in order from the object side. And the second lens group independently move in the optical axis direction, and the second lens group has two lens groups, that is, a twenty-first lens group and a twenty-second lens group having a refracting power of the same sign. It is characterized in that focusing is performed by the 22nd lens group.

【００１０】（１−２）物体側より順に負の屈折力の第
１群と正の屈折力の第２群の２つのレンズ群を有し、変
倍の際、該第１群と第２群は各々独立に光軸上移動し、
該第２群は共に正の屈折力の第２１レンズ群と第２２レ
ンズ群の２つのレンズ群を有し、該第２１レンズ群又は
第２２レンズ群でフォーカスしていることを特徴として
いる。(1-2) It has two lens groups, a first lens group having a negative refractive power and a second lens group having a positive refractive power, which are arranged in this order from the object side. Each group moves independently on the optical axis,
The second lens group has two lens groups, a 21st lens group and a 22nd lens group, both of which have positive refractive power, and is characterized by being focused by the 21st lens group or the 22nd lens group.

【００１１】（１−３）物体側より順に負の屈折力の第
１群と正の屈折力の第２群そして負の屈折力の第３群の
３つのレンズ群を有し、変倍の際、該第１群と第２群そ
して該第３群は各々独立に光軸上移動し、該第２群は共
に正の屈折力の第２１レンズ群と第２２レンズ群の２つ
のレンズ群を有し、該第２１レンズ群又は第２２レンズ
群でフォーカスしていることを特徴としている。(1-3) It has three lens groups, a first group having a negative refractive power, a second group having a positive refractive power, and a third group having a negative refractive power, which are arranged in order from the object side. At this time, the first lens group, the second lens group, and the third lens group move independently on the optical axis, and the second lens group has two lens groups of positive refractive power, that is, a twenty-first lens group and a twenty-second lens group. And is focused by the 21st lens group or the 22nd lens group.

【００１２】[0012]

【実施例】図１〜図４は本発明の数値実施例１〜４のズ
ームレンズの広角端におけるレンズ断面図である。図中
Ｌ１は負の屈折力の第１群、Ｌ２は正の屈折力の第２
群、Ｌ３は負の屈折力の第３群、Ｌ４は正の屈折力の第
４群である。ＳＰは絞り、ＩＰは像面である。矢印は広
角端から望遠端への変倍を行う際の各レンズ群の移動軌
跡を示している。1 to 4 are lens cross-sectional views at the wide-angle end of zoom lenses according to Numerical Embodiments 1 to 4 of the present invention. In the figure, L1 is the first group of negative refractive power, and L2 is the second group of positive refractive power.
L3 is a third group having a negative refractive power, and L4 is a fourth group having a positive refractive power. SP is an aperture and IP is an image plane. The arrows indicate the movement loci of the respective lens groups when zooming from the wide-angle end to the telephoto end.

【００１３】第２群Ｌ２は正の屈折力の第２１レンズ群
Ｌ２１と正の屈折力の第２２レンズ群Ｌ２２の２つのレ
ンズ群を有している。The second lens unit L2 has two lens units, a 21st lens unit L21 having a positive refractive power and a 22nd lens unit L22 having a positive refractive power.

【００１４】本実施例では図１に示すように広角端から
望遠端への変倍に際しては第１群Ｌ１を像面側に凸状の
軌跡を有しつつ移動させて変倍に伴う像面変動を補正
し、第２群Ｌ２を第２群と第１群との間隔が小さくなる
ように移動させ、第３群Ｌ３を第３群と第２群との間隔
が大きくなるように移動させ、第４群Ｌ４を第４群と第
３群との間隔が小さくなるように移動させている。尚第
２群と第４群は一体的に移動させても良い。フォーカス
は第２群の一部のレンズ群を移動させて行っている。In this embodiment, as shown in FIG. 1, during zooming from the wide-angle end to the telephoto end, the first lens unit L1 is moved while having a convex locus on the image surface side, and the image surface accompanying zooming is changed. The fluctuation is corrected, the second lens unit L2 is moved so that the distance between the second lens unit and the first lens unit becomes small, and the third lens unit L3 is moved so that the distance between the third lens unit and the second lens unit becomes large. , The fourth lens unit L4 is moved so that the distance between the fourth lens unit and the third lens unit becomes small. The second group and the fourth group may be moved integrally. Focusing is performed by moving a part of the second lens group.

【００１５】具体的には第２群Ｌ２を正の屈折力の第２
１レンズ群Ｌ２１と第２２レンズ群Ｌ２２の２つのレン
ズ群に分け、このうち第２１レンズ群Ｌ２１を像面側へ
移動させて無限遠物体から至近物体へのフォーカスを行
っている。このように第２群を同符号の正の屈折力の２
つのレンズ群Ｌ２１，Ｌ２２に分け、このうち一方のレ
ンズ群でフォーカスを行うことにより各レンズ群Ｌ２
１，Ｌ２２の屈折力を強くする必要がなく、この結果第
２群のレンズ枚数を少なくすることができ、又フォーカ
スの際の収差変動が少なくなるようにしている。Specifically, the second lens unit L2 is set to the second lens unit having a positive refractive power.
It is divided into two lens groups, a first lens group L21 and a twenty-second lens group L22. Of these, the twenty-first lens group L21 is moved to the image plane side to focus from an object at infinity to a near object. In this way, the second lens group having a positive refractive power of the same sign is
Each lens group L2 is divided into two lens groups L21 and L22, and focusing is performed by one of the lens groups L2 and L2.
It is not necessary to increase the refracting power of L1 and L22, and as a result, the number of lenses in the second group can be reduced, and the fluctuation of aberrations during focusing is reduced.

【００１６】本実施例では第２群の一部分のレンズ群で
フォーカスを行う方法を採り、又第２群の最終レンズ面
よりも像面側に絞りを配置する構成としている。これに
より例えば、該レンズ群の周囲に自動焦点検出ユニット
を装着し、第２群以降のレンズ群の周囲に絞りユニット
を装着できるようにして、スペースの有効利用を図り、
レンズ系全体を小型にしている。In this embodiment, a method of focusing with a lens group which is a part of the second lens group is adopted, and the diaphragm is arranged closer to the image surface side than the final lens surface of the second lens group. With this, for example, an automatic focus detection unit can be mounted around the lens group, and a diaphragm unit can be mounted around the lens groups of the second and subsequent lens groups to effectively use the space.
The entire lens system is compact.

【００１７】本実施例ではこのように各レンズ群の屈折
力や変倍及びフォーカスにおける各レンズ群の移動条件
を設定することにより、レンズ全長を短縮しつつ、広画
角で全変倍範囲及び物体距離全般にわたり高い光学性能
を有したズームレンズを得ている。In this embodiment, by setting the refracting power of each lens group and the moving conditions of each lens group in zooming and focusing in this way, the total lens length is shortened and the total zooming range and wide zooming range are widened. We have obtained a zoom lens with high optical performance over the entire object distance.

【００１８】本発明のインナーフォーカス式のズームレ
ンズは以上の構成要件を満足することにより達成される
が、更にフォーカスの際の収差変動を少なくしつつ物体
距離全般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 inner focus type zoom lens according to the present invention can be achieved by satisfying the above-mentioned requirements. To obtain high optical performance over the entire object distance while further reducing the fluctuation of aberration during focusing, It is preferable to satisfy at least one of the above conditions.

【００１９】（２−１）前記レンズ群Ｌ２１，Ｌ２２の
焦点距離を各々ｆ２１，ｆ２２としたとき ０．２＜ｆ２２／ｆ２１＜１．２ ‥‥‥（１） なる条件を満足することである。(2-1) When the focal lengths of the lens units L21 and L22 are f21 and f22, respectively, 0.2 <f22 / f21 <1.2 (1) is satisfied. .

【００２０】条件式（１）は第２群の２つのレンズ群の
正の屈折力の比に関し、主に色収差と球面収差をバラン
ス良く補正する為のものである。条件式（１）の下限値
を越えてフォーカス用の第２１レンズ群Ｌ２１の屈折力
が第２２レンズ群Ｌ２２の屈折力に比べて強くなりすぎ
ると望遠側での軸上色収差の補正が難しくなってくる。
条件式（１）の上限値を越えてフォーカス用の第２１レ
ンズ群Ｌ２１の屈折力が第２２レンズ群Ｌ２２の屈折力
に比べて弱くなりすぎると広角側において輪帯球面収差
が大きくなってくるので良くない。Conditional expression (1) relates to the ratio of the positive refracting powers of the two lens groups of the second lens group, and is mainly for correcting chromatic aberration and spherical aberration in a well-balanced manner. When the lower limit of conditional expression (1) is exceeded and the refractive power of the 21st lens unit L21 for focusing becomes too strong as compared with the refractive power of the 22nd lens unit L22, it becomes difficult to correct axial chromatic aberration on the telephoto side. Come on.
When the upper limit of conditional expression (1) is exceeded and the refracting power of the 21st lens unit L21 for focusing becomes too weak as compared with the refracting power of the 22nd lens unit L22, annular spherical aberration becomes large on the wide-angle side. So not good.

【００２１】（２−２）前記第ｉ群の焦点距離をｆｉと
したとき ０．１＜ｆ２／ｆ２１＜ ０．８ ‥‥‥（２） −１．０＜ｆ２／ｆ１ ＜−０．４ ‥‥‥（３） なる条件を満足することである。(2-2) When the focal length of the i-th group is fi 0.1 <f2 / f21 <0.8 (2) -1.0 <f2 / f1 <-0.4 (3) To satisfy the following condition.

【００２２】条件式（２）は第２群の屈折力と第２１レ
ンズ群Ｌ２１の屈折力の比に関し、主に球面収差を良好
に補正する為のものである。条件式（２）の下限値を越
えて第２群の正の屈折力が強くなりすぎると広角側での
球面収差の補正が難しくなってくる。又条件式（２）の
上限値を越えて第２群の正の屈折力が弱くなりすぎると
所定の変倍比を確保する為の第２群の移動量が多くな
り、レンズ全長が増大してくるので良くない。Conditional expression (2) relates to the ratio of the refracting power of the second lens unit to the refracting power of the 21st lens unit L21, and is mainly for favorably correcting spherical aberration. If the lower limit of conditional expression (2) is exceeded and the positive refractive power of the second lens unit becomes too strong, it becomes difficult to correct spherical aberration on the wide angle side. Further, if the upper limit of conditional expression (2) is exceeded and the positive refractive power of the second lens unit becomes too weak, the amount of movement of the second lens unit to secure a predetermined zoom ratio increases, and the total lens length increases. It's not good because it comes.

【００２３】条件式（３）は第１群の屈折力と第２群の
屈折力の比に関し、主にレンズ全長の短縮化を図りつつ
色収差を良好に補正する為のものである。条件式（３）
の下限値を越えて第１群の屈折力が弱くなりすぎると変
倍に伴う第１群の移動量が多くなり、レンズ全長が増大
してくる。又条件式（３）の上限値を越えて第１群の屈
折力が強くなりすぎると広角側において倍率色収差が増
大してくるので良くない。Conditional expression (3) relates to the ratio of the refracting power of the first lens group to the refracting power of the second lens group, and is for mainly correcting the chromatic aberration while shortening the overall lens length. Conditional expression (3)
If the refractive power of the first lens unit becomes too weak below the lower limit of the above, the amount of movement of the first lens unit due to zooming increases and the total lens length increases. If the upper limit of conditional expression (3) is exceeded and the refractive power of the first lens unit becomes too strong, lateral chromatic aberration will increase on the wide angle side, which is not preferable.

【００２４】（２−３）第１群を両レンズ面が凹面の負
レンズ、物体側へ凸面を向けたメニスカス状の正レンズ
より構成し、第２群の第２１レンズ群Ｌ２１を負レンズ
と正レンズとの接合レンズ又は正，負，正レンズの３つ
のレンズの接合レンズより構成し、第２２レンズ群Ｌ２
２を１つの正レンズ又は正レンズと負レンズの２つのレ
ンズより構成し、第３群を負レンズと正レンズより構成
し、第４群を両レンズ面が凸面の正レンズと像面側に凸
面を向けたメニスカス状の正レンズより構成するのが良
い。(2-3) The first lens unit is composed of a negative lens whose both lens surfaces are concave surfaces and a meniscus positive lens whose convex surface faces the object side, and the 21st lens unit L21 of the second lens group is a negative lens. A cemented lens with a positive lens or a cemented lens of three lenses, a positive lens, a negative lens, and a positive lens, and the 22nd lens unit L2
2 is composed of one positive lens or two lenses of a positive lens and a negative lens, the third group is composed of a negative lens and a positive lens, and the fourth group is composed of a positive lens whose both lens surfaces are convex surfaces and an image surface side. It is preferably composed of a positive meniscus lens having a convex surface.

【００２５】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。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、Ｂ，Ｃ，Ｄを各々非球面係
数としたとき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. When the aspherical shape is the X axis in the optical axis direction, the H axis in the direction perpendicular to the optical axis, the traveling direction of light is positive, R is the paraxial radius of curvature, and B, C, and D are aspherical coefficients, respectively.

【００２６】[0026]

【数１】 なる式で表わしている。又「Ｄ−０Ｘ」は「１０^-X」を
意味している。[Equation 1] It is expressed by Also, "D-0X" means "10 ^-X ".

【００２７】 〈数値実施例１〉 F= 38.29 fno=1:3.2〜5.6 2ω= 65.6°〜27.4° R 1= -269.74 D 1= 1.78 N 1=1.77250 ν 1= 49.6 R 2= 17.99 D 2= 5.30 N 2=1.84666 ν 2= 23.8 R 3= 29.60 D 3= 可変 R 4= 23.86 D 4= 1.43 N 3=1.84666 ν 3= 23.8 R 5= 15.43 D 5= 5.74 N 4=1.48749 ν 4= 64.9 R 6= -696.40 D 6= 4.34 R 7= 21.65 D 7= 5.90 N 5=1.69680 ν 5= 55.5 R 8= -53.89 D 8= 0.28 R 9= -67.22 D 9= 1.43 N 6=1.69680 ν 6= 30.0 R10= 117.20 D10= 可変 R11=（絞り） D11= 2.27 R12= -35.35 D12= 2.15 N 7=1.84666 ν 7= 23.8 R13= -22.82 D13= 0.28 R14= -24.53 D14= 1.43 N 8=1.60311 ν 8= 60.8 R15= 53.29 D15= 可変 R16= 25.12 D16= 5.30 N 9=1.60729 ν 9= 49.2 R17= -24.58 D17= 1.00 R18= -18.97 D18= 1.43 N10=1.69895 ν10= 42.1 R19= 100.82 ｆ２２／ｆ２１＝ ０．４７ ｆ２／ｆ２１＝ ０．３４ ｆ２／ｆ１ ＝−０．７０ 非球面係数 Ｒ ３ Ｋ=-3.853 D-01 Ｂ= 2.103 D-06 Ｃ=-4.557 D-09 Ｄ= 1.928 D-11 Ｒ１７ Ｋ=-1.474 D-01 Ｂ= 3.181 D-05 Ｃ= 7.523 D-08 Ｄ=-5.226 D-10Numerical Example 1 F = 38.29 fno = 1: 3.2 to 5.6 2ω = 65.6 ° to 27.4 ° R 1 = -269.74 D 1 = 1.78 N 1 = 1.77250 ν 1 = 49.6 R 2 = 17.99 D 2 = 5.30 N 2 = 1.84666 ν 2 = 23.8 R 3 = 29.60 D 3 = Variable R 4 = 23.86 D 4 = 1.43 N 3 = 1.84666 ν 3 = 23.8 R 5 = 15.43 D 5 = 5.74 N 4 = 1.48749 ν 4 = 64.9 R 6 = -696.40 D 6 = 4.34 R 7 = 21.65 D 7 = 5.90 N 5 = 1.69680 ν 5 = 55.5 R 8 = -53.89 D 8 = 0.28 R 9 = -67.22 D 9 = 1.43 N 6 = 1.69680 ν 6 = 30.0 R10 = 117.20 D10 = Variable R11 = (Aperture) D11 = 2.27 R12 = -35.35 D12 = 2.15 N 7 = 1.84666 ν 7 = 23.8 R13 = -22.82 D13 = 0.28 R14 = -24.53 D14 = 1.43 N 8 = 1.60311 ν 8 = 60.8 R15 = 53.29 D15 = Variable R16 = 25.12 D16 = 5.30 N 9 = 1.60729 ν 9 = 49.2 R17 = -24.58 D17 = 1.00 R18 = -18.97 D18 = 1.43 N10 = 1.69895 ν10 = 42.1 R19 = 100.82 f22 / f21 = 0. 47 f2 / f21 = 0.34 f2 / f1 = −0.70 Aspheric coefficient R 3 K = -3.853 D-01 B = 2.103 D-06 C = -4.557 D-09 D = 1.928 D-11 R17 K = -1.474 D-01 B = 3.181 D-05 C = 7.523 D-08 D = -5.226 D -Ten

【００２８】[0028]

【表１】 〈数値実施例２〉 F= 38.32 fno=1:3.2〜5.6 2ω= 65.6°〜27.4° R 1= -160.76 D 1= 1.84 N 1=1.77250 ν 1= 49.6 R 2= 20.62 D 2= 0.54 R 3= 22.49 D 3= 4.70 N 2=1.84666 ν 2= 23.8 R 4= 36.42 D 4= 可変 R 5= 32.15 D 5= 1.43 N 3=1.84666 ν 3= 23.8 R 6= 18.46 D 6= 6.22 N 4=1.48749 ν 4= 70.2 R 7= -48.04 D 7= 3.66 R 8= 18.33 D 8= 5.71 N 5=1.69680 ν 5= 55.5 R 9= -613.18 D 9= 0.09 R10= 582.31 D10= 1.43 N 6=1.69680 ν 6= 51.2 R11= 31.13 D11= 可変 R12=（絞り） D12= 1.65 R13= 3195.99 D13= 1.43 N 7=1.65844 ν 7= 48.3 R14= 16.24 D14= 0.18 R15= 15.51 D15= 2.33 N 8=1.80518 ν 8= 25.4 R16= 27.58 D16= 可変 R17= 40.23 D17= 4.82 N 9=1.53256 ν 9= 45.9 R18= -18.85 D18= 1.53 R19= -12.71 D19= 1.43 N10=1.69895 ν10= 30.0 R20= -36.27 ｆ２２／ｆ２１＝ ０．７９ ｆ２／ｆ２１＝ ０．４５ ｆ２／ｆ１ ＝−０．７５ 非球面係数 Ｒ３ Ｋ= 3.749 D-02 Ｂ= 2.823 D-06 Ｃ= 3.802 D-09 Ｄ= 3.214 D-11[Table 1] <Numerical Example 2> F = 38.32 fno = 1: 3.2 to 5.6 2 ω = 65.6 ° to 27.4 ° R 1 = -160.76 D 1 = 1.84 N 1 = 1.77250 ν 1 = 49.6 R 2 = 20.62 D 2 = 0.54 R 3 = 22.49 D 3 = 4.70 N 2 = 1.84666 ν 2 = 23.8 R 4 = 36.42 D 4 = Variable R 5 = 32.15 D 5 = 1.43 N 3 = 1.84666 ν 3 = 23.8 R 6 = 18.46 D 6 = 6.22 N 4 = 1.48749 ν 4 = 70.2 R 7 = -48.04 D 7 = 3.66 R 8 = 18.33 D 8 = 5.71 N 5 = 1.69680 ν 5 = 55.5 R 9 = -613.18 D 9 = 0.09 R10 = 582.31 D10 = 1.43 N 6 = 1.69680 ν 6 = 51.2 R11 = 31.13 D11 = Variable R12 = (Aperture) D12 = 1.65 R13 = 3195.99 D13 = 1.43 N 7 = 1.65844 ν 7 = 48.3 R14 = 16.24 D14 = 0.18 R15 = 15.51 D15 = 2.33 N 8 = 1.80518 ν 8 = 25.4 R16 = 27.58 D16 = Variable R17 = 40.23 D17 = 4.82 N 9 = 1.53256 ν 9 = 45.9 R18 = -18.85 D18 = 1.53 R19 = -12.71 D19 = 1.43 N10 = 1.69895 ν10 = 30.0 R20 = -36.27 f22 / f21 = 0. 79 f2 / f21 = 0.45 f2 / f1 = -0.75 Aspheric coefficient R3 K = 3.749 D-02 B = 2.823 D-06 C = 3.802 D-09 D = 3.214 D-11

【００２９】[0029]

【表２】 〈数値実施例３〉 F= 38.32 fno=1:3.2〜5.6 2ω= 65.6°〜27.4° R 1= -130.04 D 1= 1.68 N 1=1.77250 ν 1= 49.6 R 2= 19.37 D 2= 0.79 R 3= 22.16 D 3= 3.97 N 2=1.84666 ν 2= 23.8 R 4= 38.51 D 4= 可変 R 5= 33.51 D 5= 2.86 N 3=1.69680 ν 3= 30.0 R 6= 496.49 D 6= 1.43 N 4=1.84666 ν 4= 23.8 R 7= 18.11 D 7= 5.00 N 5=1.63854 ν 5= 55.4 R 8= -66.83 D 8= 3.33 R 9= 18.67 D 9= 4.14 N 6=1.60311 ν 6= 41.8 R10= 50.29 D10= 可変 R11=（絞り） D11= 1.85 R12= 322.45 D12= 1.43 N 7=1.65844 ν 7= 55.0 R13= 16.53 D13= 0.26 R14= 16.23 D14= 1.91 N 8=1.80518 ν 8= 25.4 R15= 29.77 D15= 可変 R16= 48.88 D16= 4.29 N 9=1.53256 ν 9= 51.8 R17= -20.85 D17= 1.62 R18= -13.70 D18= 1.43 N10=1.68893 ν10= 31.1 R19= -43.79 ｆ２２／ｆ２１＝ ０．８９ ｆ２／ｆ２１＝ ０．５０ ｆ２／ｆ１ ＝−０．７８ 非球面係数 Ｒ２ Ｋ=-3.402 D-01 Ｂ= 5.047 D-07 Ｃ=-6.952 D-09 Ｄ= 7.616 D-12[Table 2] Numerical Example 3 F = 38.32 fno = 1: 3.2 to 5.6 2 ω = 65.6 ° to 27.4 ° R 1 = -130.04 D 1 = 1.68 N 1 = 1.77250 ν 1 = 49.6 R 2 = 19.37 D 2 = 0.79 R 3 = 22.16 D 3 = 3.97 N 2 = 1.84666 ν 2 = 23.8 R 4 = 38.51 D 4 = Variable R 5 = 33.51 D 5 = 2.86 N 3 = 1.69680 ν 3 = 30.0 R 6 = 496.49 D 6 = 1.43 N 4 = 1.84666 ν 4 = 23.8 R 7 = 18.11 D 7 = 5.00 N 5 = 1.63854 ν 5 = 55.4 R 8 = -66.83 D 8 = 3.33 R 9 = 18.67 D 9 = 4.14 N 6 = 1.60311 ν 6 = 41.8 R10 = 50.29 D10 = Variable R11 = (Aperture) D11 = 1.85 R12 = 322.45 D12 = 1.43 N 7 = 1.65844 ν 7 = 55.0 R13 = 16.53 D13 = 0.26 R14 = 16.23 D14 = 1.91 N 8 = 1.80518 ν 8 = 25.4 R15 = 29.77 D15 = Variable R16 = 48.88 D16 = 4.29 N 9 = 1.53256 ν 9 = 51.8 R17 = -20.85 D17 = 1.62 R18 = -13.70 D18 = 1.43 N10 = 1.68893 ν10 = 31.1 R19 = -43.79 f22 / f21 = 0.89 f2 / f21 = 0. 50 f2 / f1 = -0.78 Aspheric coefficient R2 K = -3.402 D-01 B = 5.047 D-07 C = -6.952 D-09 D = 7.616 D-12

【００３０】[0030]

【表３】 〈数値実施例４〉 F= 38.63 fno=1:3.2〜5.6 2ω= 65.6°〜27.4° R 1= -145.56 D 1= 1.68 N 1=1.77250 ν 1= 55.5 R 2= 21.87 D 2= 0.34 R 3= 22.56 D 3= 3.97 N 2=1.84666 ν 2= 23.8 R 4= 35.44 D 4= 可変 R 5= 33.25 D 5= 1.43 N 3=1.84666 ν 3= 23.8 R 6= 18.82 D 6= 6.43 N 4=1.48749 ν 4= 70.2 R 7= -40.64 D 7= 3.71 R 8= 16.84 D 8= 4.14 N 5=1.60311 ν 5= 60.8 R 9= 33.78 D 9= 可変 R10=（絞り） D10= 1.69 R11= 515.48 D11= 1.43 N 6=1.65844 ν 6= 41.3 R12= 18.52 D12= 0.26 R13= 16.68 D13= 1.91 N 7=1.80518 ν 7= 25.4 R14= 28.82 D14= 可変 R15= 62.68 D15= 4.29 N 8=1.59270 ν 8= 35.3 R16= -21.36 D16= 1.82 R17= -13.02 D17= 1.43 N 9=1.69895 ν 9= 28.0 R18= -39.28 ｆ２２／ｆ２１＝ ０．９３ ｆ２／ｆ２１＝ ０．５０ ｆ２／ｆ１ ＝−０．７４ 非球面係数 Ｒ２ Ｋ=-3.491 D-01 Ｂ= 2.704 D-06 Ｃ=-2.622 D-09 Ｄ= 2.400 D-11[Table 3] <Numerical Example 4> F = 38.63 fno = 1: 3.2 to 5.6 2 ω = 65.6 ° to 27.4 ° R 1 = -145.56 D 1 = 1.68 N 1 = 1.77250 ν 1 = 55.5 R 2 = 21.87 D 2 = 0.34 R 3 = 22.56 D 3 = 3.97 N 2 = 1.84666 ν 2 = 23.8 R 4 = 35.44 D 4 = Variable R 5 = 33.25 D 5 = 1.43 N 3 = 1.84666 ν 3 = 23.8 R 6 = 18.82 D 6 = 6.43 N 4 = 1.48749 ν 4 = 70.2 R 7 = -40.64 D 7 = 3.71 R 8 = 16.84 D 8 = 4.14 N 5 = 1.60311 ν 5 = 60.8 R 9 = 33.78 D 9 = Variable R10 = (Aperture) D10 = 1.69 R11 = 515.48 D11 = 1.43 N 6 = 1.65844 ν 6 = 41.3 R12 = 18.52 D12 = 0.26 R13 = 16.68 D13 = 1.91 N 7 = 1.80518 ν 7 = 25.4 R14 = 28.82 D14 = Variable R15 = 62.68 D15 = 4.29 N 8 = 1.59270 ν 8 = 35.3 R16 = -21.36 D16 = 1.82 R17 = -13.02 D17 = 1.43 N 9 = 1.69895 ν 9 = 28.0 R18 = -39.28 f22 / f21 = 0.93 f2 / f21 = 0.50 f2 / f1 = -0.74 Aspheric coefficient R2 K = -3.491 D-01 B = 2.704 D-06 C = -2.622 D-09 D = 2.400 D-11

【００３１】[0031]

【表４】 [Table 4]

【００３２】[0032]

【発明の効果】本発明によれば以上のように、第２群の
一部のレンズ群でフォーカスを行うインナーフォーカス
方式を採用しつつ、高変倍化を図ると共にレンズ系全体
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自動焦点検
出装置を有したカメラや防水用カメラ等に好適なインナ
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 inner focus system in which a part of the second lens group is used for focusing, a high zoom ratio is achieved and the overall size of the lens system is reduced. While aiming, a camera or waterproof camera with an automatic focus detection device that 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. It is possible to achieve an inner focus type zoom lens suitable for the above.

【図面の簡単な説明】[Brief description of drawings]

【図１】 本発明の数値実施例１の広角端のレンズ断面
図FIG. 1 is a lens cross-sectional view at a wide-angle end according to Numerical Example 1 of the present invention.

【図２】 本発明の数値実施例２の広角端のレンズ断面
図FIG. 2 is a lens cross-sectional view at a wide-angle end according to Numerical Example 2 of the present invention.

【図３】 本発明の数値実施例３の広角端のレンズ断面
図FIG. 3 is a lens cross-sectional view at a wide-angle end according to Numerical Example 3 of the present invention.

【図４】 本発明の数値実施例４の広角端のレンズ断面
図FIG. 4 is a lens cross-sectional view at a wide-angle end according to Numerical Example 4 of the present invention.

【図５】 本発明の数値実施例１の無限遠物体の広角端
の収差図FIG. 5 is an aberration diagram at a wide-angle end of an object at infinity according to Numerical Example 1 of the present invention.

【図６】 本発明の数値実施例１の無限遠物体の望遠端
の収差図FIG. 6 is an aberration diagram at a telephoto end of an object at infinity according to Numerical Example 1 of the present invention.

【図７】 本発明の数値実施例１の物体距離１ｍの広角
端の収差図FIG. 7 is an aberration diagram at a wide-angle end with an object distance of 1 m according to Numerical Example 1 of the present invention.

【図８】 本発明の数値実施例１の物体距離１ｍの望遠
端の収差図FIG. 8 is an aberration diagram at a telephoto end with an object distance of 1 m according to Numerical Example 1 of the present invention.

【図９】 本発明の数値実施例２の無限遠物体の広角端
の収差図FIG. 9 is an aberration diagram at the wide-angle end of an object at infinity according to Numerical Example 2 of the present invention.

【図１０】本発明の数値実施例２の無限遠物体の望遠端
の収差図FIG. 10 is an aberration diagram at a telephoto end of an object at infinity according to Numerical Example 2 of the present invention.

【図１１】本発明の数値実施例２の物体距離１ｍの広角
端の収差図FIG. 11 is an aberration diagram at a wide-angle end with an object distance of 1 m according to Numerical Example 2 of the present invention.

【図１２】本発明の数値実施例２の物体距離１ｍの望遠
端の収差図FIG. 12 is an aberration diagram at a telephoto end with an object distance of 1 m according to Numerical Example 2 of the present invention.

【図１３】本発明の数値実施例３の無限遠物体の広角端
の収差図FIG. 13 is an aberration diagram of a wide-angle end of an object at infinity according to Numerical Example 3 of the present invention.

【図１４】本発明の数値実施例３の無限遠物体の望遠端
の収差図FIG. 14 is an aberration diagram at a telephoto end of an object at infinity according to Numerical Example 3 of the present invention.

【図１５】本発明の数値実施例３の物体距離１ｍの広角
端の収差図FIG. 15 is an aberration diagram at a wide-angle end with an object distance of 1 m according to Numerical Example 3 of the present invention.

【図１６】本発明の数値実施例３の物体距離１ｍの望遠
端の収差図FIG. 16 is an aberration diagram at a telephoto end for an object distance of 1 m according to Numerical Example 3 of the present invention.

【図１７】本発明の数値実施例４の無限遠物体の広角端
の収差図FIG. 17 is an aberration diagram at a wide-angle end of an object at infinity according to Numerical Example 4 of the present invention.

【図１８】本発明の数値実施例４の無限遠物体の望遠端
の収差図FIG. 18 is an aberration diagram at a telephoto end of an object at infinity according to Numerical Example 4 of the present invention.

【図１９】本発明の数値実施例４の物体距離１ｍの広角
端の収差図FIG. 19 is an aberration diagram at a wide-angle end with an object distance of 1 m according to Numerical Example 4 of the present invention.

【図２０】本発明の数値実施例４の物体距離１ｍの望遠
端の収差図FIG. 20 is an aberration diagram at a telephoto end with an object distance of 1 m according to Numerical Example 4 of the present invention.

【符号の説明】[Explanation of symbols]

Ｌ１ 第１群 Ｌ２ 第２群 Ｌ３ 第３群 Ｌ４ 第４群 Ｌ２１ 第２１群 Ｌ２２ 第２２群 ＳＰ 絞り ＩＰ 像面 ｄ ｄ線 ｇ ｇ線 Ｓ．Ｃ 正弦条件 ΔＭ メリディオナル像面 ΔＳ サジタル像面 L1 1st group L2 2nd group L3 3rd group L4 4th group L21 21st group L22 22nd group SP diaphragm IP image surface d d line g g line S.I. C Sine condition ΔM Meridional image plane ΔS Sagittal image plane

Claims (7)

【特許請求の範囲】[Claims] 【請求項１】 物体側より順に第１群，第２群のレンズ
群が存在し、変倍時該第１群と第２群は独立して光軸方
向に動き、該第２群は同一の符号の屈折力の第２１レン
ズ群と第２２レンズ群の２つのレンズ群を有し、該第２
１レンズ群又は第２２レンズ群でフォーカスしているこ
とを特徴とするインナーフォーカス式のズームレンズ。1. A first lens group and a second lens group are present in this order from the object side, the first lens group and the second lens group move independently in the optical axis direction during zooming, and the second lens group is the same. A second lens group having a refracting power of 21 and a second lens group having a refractive power of 22.
An inner focus type zoom lens characterized by being focused by the first lens group or the 22nd lens group. 【請求項２】 物体側より順に負の屈折力の第１群と正
の屈折力の第２群の２つのレンズ群を有し、変倍の際、
該第１群と第２群は各々独立に光軸上移動し、該第２群
は共に正の屈折力の第２１レンズ群と第２２レンズ群の
２つのレンズ群を有し、該第２１レンズ群又は第２２レ
ンズ群でフォーカスしていることを特徴とするインナー
フォーカス式のズームレンズ。2. A lens unit having two lens units, a first unit having a negative refracting power and a second unit having a positive refracting power, which are arranged in order from the object side.
The first group and the second group independently move on the optical axis, and the second group has two lens groups, a 21st lens group and a 22nd lens group, both of which have positive refractive power. An inner focus type zoom lens characterized by being focused by a lens group or a 22nd lens group. 【請求項３】 物体側より順に負の屈折力の第１群と正
の屈折力の第２群そして負の屈折力の第３群の３つのレ
ンズ群を有し、変倍の際、該第１群と第２群そして該第
３群は各々独立に光軸上移動し、該第２群は共に正の屈
折力の第２１レンズ群と第２２レンズ群の２つのレンズ
群を有し、該第２１レンズ群又は第２２レンズ群でフォ
ーカスしていることを特徴とするインナーフォーカス式
のズームレンズ。3. It has three lens groups, a first group having a negative refractive power, a second group having a positive refractive power, and a third group having a negative refractive power in order from the object side. The first lens group, the second lens group, and the third lens group move independently on the optical axis, and the second lens group has two lens groups, a 21st lens group and a 22nd lens group, each having a positive refractive power. An inner focus type zoom lens characterized in that focusing is performed by the 21st lens group or the 22nd lens group. 【請求項４】 前記第２群の最終レンズ面より像面側に
絞りを設けたことを特徴とする請求項１，２又は３のイ
ンナーフォーカス式のズームレンズ。4. The inner focus type zoom lens according to claim 1, wherein a stop is provided closer to the image surface side than the final lens surface of the second group. 【請求項５】 前記レンズ群Ｌ２１，Ｌ２２の焦点距離
を各々ｆ２１，ｆ２２としたとき ０．２＜ｆ２２／ｆ２１＜１．２ なる条件を満足することを特徴とする請求項１，２，３
又は４のインナーフォーカス式のズームレンズ。5. The conditions satisfying 0.2 <f22 / f21 <1.2 when the focal lengths of the lens groups L21 and L22 are f21 and f22, respectively.
Or 4 inner focus type zoom lens. 【請求項６】 前記第ｉ群の焦点距離をｆｉとしたとき ０．１＜ｆ２／ｆ２１＜ ０．８ −１．０＜ｆ２／ｆ１ ＜−０．４ なる条件を満足することを特徴とする請求項１〜５の何
れか１項記載のインナーフォーカス式のズームレンズ。6. When the focal length of the i-th group is fi, the condition of 0.1 <f2 / f21 <0.8-1.0 <f2 / f1 <-0.4 is satisfied. The inner focus type zoom lens according to any one of claims 1 to 5. 【請求項７】 物体側より順に負の屈折力の第１群、正
の屈折力の第２群、負の屈折力の第３群、そして正の屈
折力の第４群の４つのレンズ群を有し、広角端から望遠
端への変倍に際しては各レンズ群を物体側へ移動させ、
該第２群は共に正の屈折力の第２１レンズ群と第２２レ
ンズ群の２つのレンズ群を有し、該第２１レンズ群又は
第２２レンズ群でフォーカスを行い、第ｉ群の焦点距離
をｆｉ、該レンズ群Ｌ２１，Ｌ２２の焦点距離を各々ｆ
２１，ｆ２２としたとき ０．２＜ｆ２２／ｆ２１＜ １．２ ０．１＜ｆ２ ／ｆ２１＜ ０．８ −１．０＜ｆ２ ／ｆ１ ＜−０．４ なる条件を満足することを特徴とするインナーフォーカ
ス式のズームレンズ。7. The four lens groups, in order from the object side, a first group having a negative refractive power, a second group having a positive refractive power, a third group having a negative refractive power, and a fourth group having a positive refractive power. And when moving from the wide-angle end to the telephoto end, move each lens group to the object side,
The second lens group has two lens groups, a 21st lens group and a 22nd lens group, both of which have positive refractive power. Focusing is performed by the 21st lens group or the 22nd lens group, and the focal length of the i-th group is Fi and the focal lengths of the lens groups L21 and L22 are f
21 and f22, 0.2 <f22 / f21 <1.2 0.1 <f2 / f21 <0.8-1.0 <f2 / f1 <-0.4 are satisfied. An inner focus type zoom lens.