JPH01134411A - Reverse telephoto type photographic lens - Google Patents

Abstract

PURPOSE:To reduce aberrational variation over the entire range of body distance by employing the advantages of an inner focus system which performs focusing by moving a 2nd group among 1st-3rd groups. CONSTITUTION:The 1st group I with negative refracting power, the 2nd group II with positive refracting power, and the 3rd group III with positive refracting power are provided and the 2nd group II is moved on the optical axis to perform the focusing. Then an inequality I holds, where fi is the focal length of an (i)th group, (f) the focal length of the whole system, phi3B the refracting power of the cemented lens surface of the cemented lens of the 3rd group III, and R3A and R3C the radii of curvature of the lens surfaces of the cemented lens of the 3rd group III on the object side and image plane side. Consequently, the aberrational variation at the time of the focusing, specially, coma aberration and astigmatism are compensated excellently over the entire range of object distance.

Description

【発明の詳細な説明】 （産業上の利用分野） 本発明は３５１１１１カメラやビデオカメラ等に好適な
逆望遠型撮影レンズに関し、特にレンズ系中の一部のレ
ンズ群を光軸上移動させてフォーカスを行う際、物体距
離全般にわたり良好なる光学性能が得られるように構成
した逆望遠型撮影レンズに関するものである。Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a reverse telephoto photographing lens suitable for 351111 cameras, video cameras, etc., and in particular, the present invention relates to a reverse telephoto photographic lens suitable for 351111 cameras, video cameras, etc. The present invention relates to an inverted telephoto photographic lens configured to provide good optical performance over the entire object distance when focusing.

（従来の技術） 二数に撮影レンズでは被写体に焦点を合わせるのにレン
ズ系全体を光軸方向に移動させて行っている。これに対
してレンズ系中の一部のレンズ、群、例えば中間レンズ
群若しくは後方レンズ群を光軸方向に移動させて焦点合
わせな行った、所謂インナーフォーカス式やりャーフォ
ーカス式の撮影レンズが特開昭５５−１４７６０７号公
報や特開昭６１−１４０９１０号公報等で提案されてい
る。(Prior Art) Second, in a photographic lens, the entire lens system is moved in the optical axis direction to focus on the subject. On the other hand, a so-called inner focus type spear focus type photographic lens, in which focusing is achieved by moving some lenses or groups in the lens system, such as an intermediate lens group or a rear lens group, in the optical axis direction has been disclosed in Japanese Patent Application. This method has been proposed in Japanese Patent Application Laid-open No. 147607/1982 and Japanese Patent Application Laid-open No. 140910/1983.

インナーフォーカス式やりャーフォーカス式はレンズ系
全体を繰り出す方式に比べてフォーカス用レンズ群の繰
り出し量が少なく、又、フォーカス用レンズ群が比較的
小型軽量となり、小さな駆動力でフォーカスを行うこと
が出来る為、自動焦点検出装置を有したカメラ等には好
適である。この他、これらのフォーカス方式はフォーカ
スを行っても常にレンズ全長が一定である為、撮影装置
の保持がしやすくカメラプレを起こし難い等の利点があ
る。In the inner focus type spear focus type, the amount of extension of the focusing lens group is smaller than in a method in which the entire lens system is extended, and the focusing lens group is relatively small and lightweight, allowing focusing with a small driving force. , suitable for cameras with automatic focus detection devices. In addition, these focusing methods have the advantage that the overall length of the lens is always constant even when focusing, making it easier to hold the photographing device and less likely to cause camera play.

しかしながら、これらのフォーカス方式においては、一
般にレンズ系全体を繰り出すフォーカス方式に比べてフ
ォーカス用レンズ群を移動させたときに収差変動が多く
なり、物体距離全般にわたり良好に収差補正をするのが
困難になってくる。However, with these focusing methods, aberrations generally fluctuate more when the focusing lens group is moved than in focusing methods that extend the entire lens system, making it difficult to properly correct aberrations over the entire object distance. It's coming.

特に前群が負の屈折力、後群が正の屈折力のレンズ群よ
り成る所謂逆望遠型撮影レンズに右いてはこの傾向が顕
著であり、例えばフォーカスを行うと近距離物体におい
て外向性コマ収差が増大し、又、非点収差も悪化し、光
学性能を著しく低下させてくる。This tendency is particularly noticeable with so-called inverted telephoto lenses, where the front group has a negative refractive power and the rear group has a positive refractive power. Aberrations increase, and astigmatism also worsens, resulting in a significant deterioration of optical performance.

（発明が解決しようとする問題点） 本発明はインナーフォーカス式の利点を維持しつつ、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フ
ォーカスの際の収差変動、特にコマ収差と非点収差の変
動を良好に補正した高い光学性能を有した簡易な構成の
逆望遠型撮影レンズの提供を目的とする。(Problems to be Solved by the Invention) The present invention maintains the advantages of the inner focusing method, and eliminates aberration fluctuations during focusing over the entire object distance from an object at infinity to a close object, especially coma aberration and astigmatism. An object of the present invention is to provide an inverted telephoto photographing lens having a simple configuration and having high optical performance that satisfactorily corrects fluctuations in .

（問題点を解決するための手段） 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、そして正の屈折力の第３群の３つのレンズ群を有し
、前記第１群は少なくとも物体側に凸面を向けた負のメ
ニスカス状の第１１レンズと正の第１２レンズを有し、
前記第３群は負の第３１レンズと正の第３２レンズとを
貼り合わせ、このとき接合レンズ面が物体側に凸面を向
けるような形状となるような接合レンズを有し、前記第
２群を光軸上移動させることによりフォーカスを行うと
共に、前記第１群の焦点距離をｆｉ、全系の焦点距離な
ｆ、前記第３群の接合レンズの接合レンズ面の屈折力を
φ３Ｂ、前記第３群の接合レンズの物体側と像面側のレ
ンズ面の曲率半径を各々Ｒ３Ａ、Ｒ３Ｃとしたとき ３．０＜１ｆｌｌ／ｆ＜１８　　　−−−−−（１）１
、０＜　　ｆ２／ｆ　　＜１．５　　−−−−−（２）
０．０３５＜Ｉφ３Ｂｌ・ｆ＜０．０９５・・（３）ｌ
Ｒ３ｃ／Ｒ３Ａｌ　　＜２．０　　−−−−（４）なる
条件を満足することである。(Means for solving the problem) From the object side, the first group has negative refractive power, and the second group has positive refractive power.
and a third group with positive refractive power, the first group having at least a negative meniscus eleventh lens with a convex surface facing the object side and a positive twelfth lens. ,
The third group has a cemented lens in which a negative 31st lens and a positive 32nd lens are bonded together, and the cemented lens surface has a shape with a convex surface facing the object side. Focusing is performed by moving the lens on the optical axis, and the focal length of the first group is fi, the focal length of the entire system is f, the refractive power of the cemented lens surface of the cemented lens of the third group is φ3B, and the lens When the radius of curvature of the object-side and image-side lens surfaces of the cemented lens of the third group is R3A and R3C, respectively, 3.0<1fll/f<18 ----(1)1
, 0< f2/f <1.5 -------(2)
0.035<Iφ3Bl・f<0.095...(3)l
R3c/R3Al<2.0---(4) is to be satisfied.

（実施例） 第１図、第２図は各々本発明の数値実施例１゜２のレン
ズ断面図、第３図、第４図は各々本発明の数値実施例１
．２の諸収差図である。収差図において（Ａ）は無限遠
物体、（Ｂ）は至近距離（３０ｃｍ）における収差であ
る。数値実施例１は焦点距１１１２４１ＩＩＩＩｌ、Ｆ
ナンバー１．４であり、数値実施例２は焦点距離２４ｍ
ｍ、Ｆナンバー２．８である。(Example) Figures 1 and 2 are cross-sectional views of lenses of Numerical Example 1゜2 of the present invention, and Figures 3 and 4 are lens cross-sectional views of Numerical Example 1 of the present invention.
．． FIG. 2 is a diagram showing various aberrations of No. 2. In the aberration diagram, (A) shows the aberration at an object at infinity, and (B) shows the aberration at a close distance (30 cm). Numerical Example 1 has a focal length of 111241IIIl, F
The number is 1.4, and the numerical example 2 has a focal length of 24 m.
m, F number is 2.8.

第１図、第２図に３いて工は負の屈折力の第′１群、■
は正の屈折力の第２群で矢印の方向へ移動させることに
より無限遠物体から近距離物体へのフォーカスを行って
いる。■は正の屈折力の第３群である。In Figures 1 and 2, 3 indicates the '1st group with negative refractive power, ■
focuses from an object at infinity to an object at a short distance by moving the second group with positive refractive power in the direction of the arrow. (2) is the third group with positive refractive power.

本実施例では第１群を少なくとも物体側に凸面を向けた
負のメニスカス状の第１１レンズと正の第１２レンズが
レンズ系中に有するように構成し、又、第３群を負の第
３１レンズと正の第３２レンズとを貼り合わせ、このと
き貼り合わせレンズ面が物体側に凸面を向けるような形
状となるような接合レンズを有するように構成すると共
に、各レンズ群のレンズ構成を前述の条件式（１）〜（
４）を満足させることにより第２群を移動させてフォー
カスを行ったときの収差変動を良好に補正し、物体距離
全般にわたり高い光学性能を有した逆望遠型撮影レンズ
を構成している。In this embodiment, the first group is configured such that the lens system includes at least a negative meniscus-shaped eleventh lens with a convex surface facing the object side and a positive twelfth lens, and the third group is configured such that the lens system includes a negative meniscus-shaped eleventh lens with a convex surface facing the object side and a positive twelfth lens. 31 lens and a positive 32nd lens are bonded together, and at this time, the bonded lens surface is configured to have a cemented lens with a convex surface facing the object side, and the lens configuration of each lens group is Conditional expressions (1) to (
By satisfying 4), aberration fluctuations when focusing is performed by moving the second group can be well corrected, and an inverted telephoto photographing lens having high optical performance over the entire object distance is constructed.

一般に逆望遠型の撮影レンズに右いては無限遠１１影時
に比べて近距離撮影時には球面収差は補正不足、非点収
差は補正過剰、そして歪曲収差及び外向性コマ収差は増
大し、光学性能を大きく低下させる原因となっている。In general, with a reverse telephoto lens, when shooting at close range, spherical aberration is under-corrected, astigmatism is over-corrected, and distortion and extroverted coma aberration increase when shooting at close distances, compared to when shooting at infinity. This is the cause of a significant decrease.

負の屈折力の前方レンズ群を固定とし、正の屈折力の後
方レンズ群のみでフォーカスを行うリヤーフォーカス式
の逆望遠型撮影レンズにおいては、これらの各収差を補
正するために前方レンズ群から射出する光束な略アフォ
ーカルとなるように各レンズの屈折力を設定してフォー
カスを行っている。In a rear-focus type reverse telephoto photographic lens, in which the front lens group with negative refractive power is fixed and focusing is performed only with the rear lens group with positive refractive power, there is a Focusing is performed by setting the refractive power of each lens so that the emitted light beam is approximately afocal.

しかしながら、このフォーカス方式では近距離撮影にな
ると球面収差は僅かに正の方向に変位し、又、非点収差
は僅かに負の方向に変位するだけであり、コマ収差や歪
曲収差は補正不足となってくる。However, with this focusing method, when shooting at close range, spherical aberration is slightly displaced in the positive direction, astigmatism is only slightly displaced in the negative direction, and coma and distortion are under-corrected. It's coming.

この為、本実施例では特にコマ収差の変動を補正するた
めに無限遠物体の状態で、まずコマ収差を良好に補正す
る為に第１群、第２群、そして第３群の屈折力をバラン
ス良く設定して近距離物体側で大きく外向変位する第２
群までにおけるコマ収差を第３群において、前述の如く
レンズ構成を特定することにより内向方向に変位させる
ことにより相殺し、全体的にコマ収差の変動を良好に補
正している。For this reason, in this embodiment, in order to correct the fluctuation of coma aberration, first, in the state of an object at infinity, the refractive powers of the first, second, and third groups are adjusted to properly correct the coma aberration. The second set has a well-balanced setting and has a large outward displacement on the near object side.
The coma aberration in the groups up to the third group is offset by displacement in the inward direction by specifying the lens configuration as described above, and overall fluctuations in coma aberration are well corrected.

即ち、数値実施例１においては第１群で外向変位し、第
２群で僅かに内向変位し、結果的に第２群までに外向変
位したコマ収差を第３群で内向変位させたコマ収差によ
り相殺し、全体的にコマ収差の変動量を少なく抑えてい
る。That is, in Numerical Example 1, the first group is outwardly displaced, the second group is slightly inwardly displaced, and as a result, the coma aberration that has been outwardly displaced by the second group is inwardly displaced in the third group. This offsets the amount of variation in coma aberration overall.

数値実施例２においては第１群で外向変位し、同じく第
２群で外向変位し、結果的に第２群までに外向変位した
コマ収差を第３群で内向変位させたコマ収差により相殺
し、全体的にコマ収差の変動量を少なく抑えている。In Numerical Example 2, the first group is displaced outward, and the second group is also displaced outward, and as a result, the coma aberration displaced outward by the second group is offset by the coma aberration displaced inward in the third group. , the amount of variation in coma aberration is kept to a low level overall.

又、第３群中に設けられた物体側に凸面を向けた接合レ
ンズ面により近距離物体になるに従い、負の方向に変位
する歪曲収差を良好に補正している。In addition, the cemented lens surface provided in the third group and having a convex surface facing the object side satisfactorily corrects distortion that shifts in the negative direction as the distance becomes closer to the object.

次に前述の各条件式の技術的意味について説明する。Next, the technical meaning of each of the above conditional expressions will be explained.

条件式（１）は第１群の屈折力に関するものであり、上
限値を越えて負の屈折力が弱まると内向性コマ収差が大
きくなり近距離物体ヘフォーカスする際、第２群を繰り
出したときの外向性コマ収差の発生は小さくなるが、無
限遠物体では補正不足となる。下限値を越えて負の屈折
力が強くなると球面収差が補正過剰となり、又、非点収
差が悪化し、そして外向性コマ収差の外向変位が大きく
なり全体的にこれらの各収差をバランス良く補正するの
が難しくなる。Conditional expression (1) relates to the refractive power of the first group; if the negative refractive power weakens beyond the upper limit, inward coma aberration increases and the second group is extended when focusing on a short-distance object. The occurrence of extroverted coma aberration is reduced when using this lens, but it is insufficiently corrected for objects at infinity. If the lower limit is exceeded and the negative refractive power becomes strong, spherical aberration will be overcorrected, astigmatism will worsen, and the outward displacement of extroverted comatic aberration will increase, making it possible to correct each of these aberrations in a well-balanced manner overall. becomes difficult to do.

条件式（２）は第２群の屈折力に関するものであり、上
限値を越えて正の屈折力が弱まると近距離物体へ繰り出
したときの移動量が大きくなって、第１群との移動スペ
ースを充分に確保しておく必要があり、レンズ全長を実
用的な大きさに抑えることが難しくなってくる。下限値
を越えて正の屈折力が強くなると、近距離物体へ繰り出
したときの諸収差の変動が大きくなる。特に球面収差が
大きく負の方向に変位する。Conditional expression (2) relates to the refractive power of the second group, and if the positive refractive power weakens beyond the upper limit, the amount of movement when extending toward a short-distance object increases, and the movement with the first group increases. It is necessary to secure sufficient space, which makes it difficult to keep the total length of the lens to a practical size. If the lower limit is exceeded and the positive refractive power becomes strong, fluctuations in various aberrations will increase when the lens is extended toward a close object. In particular, the spherical aberration is large and is displaced in the negative direction.

条件式（３）及び条件式（４）は条件式（１）及び条件
式（２）を満足した上で、さらに諸収差を良好に補正す
るためのものであり、条件式（３）は第３群中の接合レ
ンズ面の屈折力に関するものであり、上限値を越えて屈
折力が強くなると色収差、特に倍率色収差が悪化する。Conditional expressions (3) and (4) are for satisfying conditional expressions (1) and (2) and further correcting various aberrations, and conditional expression (3) satisfies conditional expressions (1) and (2). This relates to the refractive power of the cemented lens surface in the third group, and if the refractive power becomes strong beyond the upper limit, chromatic aberration, especially chromatic aberration of magnification, worsens.

下限値を越えて屈折力が弱くなると近距離物体になるに
、つれて負の方向に変位する歪曲収差の変動を抑えるこ
とが難しくなってくる。When the refractive power becomes weaker by exceeding the lower limit value, it becomes difficult to suppress fluctuations in distortion aberration, which displaces in the negative direction, as the object becomes closer.

条件式（４）は第３群の物体側と像面側のレンズ面の曲
率半径の比を規定するものであり、条件式をはずれた場
合、Ｒ３Ａの曲率がきつく、Ｒ３Ｃの曲率がゆるくなり
球面収差が補正過剰となり、又、非点収差やコマ収差も
悪化してくる。Conditional expression (4) defines the ratio of the radius of curvature of the object-side and image-side lens surfaces of the third group, and if the conditional expression is violated, the curvature of R3A becomes tight and the curvature of R3C becomes loose. Spherical aberration becomes overcorrected, and astigmatism and coma aberration also worsen.

又、本実施例においては特にフォーカスの際の収差変動
を良好に補正する為に、第２群のレンズ構成を次の如く
設定している。Further, in this embodiment, the lens configuration of the second group is set as follows in order to particularly correct aberration fluctuations during focusing.

即ち、物体側より順に数値実施例１においては正レンズ
と像面側に強い凹面を向けた負レンズを貼り合わせた接
合レンズ、強い凸面を持った両凸レンズ、負レンズ、物
体側へ強い凹面を向けた負レンズと像面側のレンズ面が
光軸から離れるに従い正の屈折力が弱まる形状の非球面
を有した正レンズとを貼り合わせた接合レンズ、像面側
へ強い凸面を向けた正のメニスカスレンズ、そして同じ
く像面側へ凸面を向けた正のメニスカスレンズより構成
している。That is, in order from the object side, Numerical Example 1 includes a cemented lens consisting of a positive lens and a negative lens with a strongly concave surface facing the image plane, a biconvex lens with a strongly convex surface, a negative lens, and a negative lens with a strongly concave surface facing the object side. A cemented lens consisting of a negative lens that faces towards the image plane and a positive lens that has an aspherical surface whose positive refractive power weakens as the lens surface on the image side moves away from the optical axis. It consists of a meniscus lens, and a positive meniscus lens with its convex surface facing toward the image plane.

又、数値実施例２においては物体側へ凸面を向けた負の
メニスカスレンズ、正レンズ、正レンズ、両凸レンズ、
物体側へ強い凹面を向けた負レンズ、像面側へ凸面を向
けた正のメニスカスレンズ、そして同じく像面側へ凸面
を向けた正のメニスカスレンズより構成している。In addition, in Numerical Example 2, a negative meniscus lens with a convex surface facing the object side, a positive lens, a positive lens, a biconvex lens,
It consists of a negative lens with a strongly concave surface facing the object side, a positive meniscus lens with a convex surface facing the image side, and a positive meniscus lens with a convex surface facing the image side.

尚、本実施例においては第３群の物体側の負の第３１レ
ンズに低分散、像面側の正の第３°２レンズに高分散の
硝種な用いることによって色収差、特に倍率色収差を良
好に補正している。In this example, chromatic aberration, especially chromatic aberration of magnification, can be reduced by using a low-dispersion glass type for the negative 31st lens on the object side of the third group and a high-dispersion glass type for the positive 3°2 lens on the image plane side. It has been corrected.

数値実施例２においては第１群を物体側へ凸面を向けた
正のメニスカスレンズ、物体側へ凸面を向けた負のメニ
スカスレンズ、そして正レンズより構成し、諸収差をバ
ランス良く補正している。In Numerical Example 2, the first group is composed of a positive meniscus lens with a convex surface facing the object side, a negative meniscus lens with a convex surface facing the object side, and a positive lens, and various aberrations are corrected in a well-balanced manner. .

次に本発明の数値実施例を示す。数値実施例においてＲ
ｉは物体側より順に第ｉ番目のレンズ面の曲率半径、Ｄ
ｉは物体側より第ｉ番目のレンズ数値実施例１ 厚及び空気間隔、Ｎｉとυｉ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ツベ数である。Next, numerical examples of the present invention will be shown. In numerical examples R
i is the radius of curvature of the i-th lens surface in order from the object side, D
i is the i-th lens value from the object side Example 1 Thickness and air spacing, Ni and υi are the i-th lens values from the object side
These are the refractive index and Atsube number of the glass of the th lens.

又、前述の各条件式と数値実施例における語数値との関
係を表−１に示す。Furthermore, Table 1 shows the relationship between each of the above-mentioned conditional expressions and the word values in the numerical examples.

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、Ａ、Ｂ、Ｃ，
Ｄ、Ｅを各々非球面係数としたとき ＋　ＤＩ（８＋　　Ｅｌｌ” なる式で表わしている。The aspherical shape has an X axis in the optical axis direction, an H axis in a direction perpendicular to the optical axis,
The traveling direction of the light is positive, R is the paraxial radius of curvature, A, B, C,
When D and E are each aspherical coefficients, it is expressed by the formula +DI(8+Ell).

Ｒ２０−７８，５６０２０−５，ＯＮ＋２−１．７７２
５０ν１２−４９．６Ｆ　　・２４．５　　　　　ＦＮ
Ｏ−１：１．４５　　　　　２（ＩＪ−８２，９゜Ｒｌ
−７４，８２Ｄ　　Ｉ−２，０Ｎ　　ト弓、６０３１１
　　ｖ　　１−６０．７Ｉｔ　　２−　　３２．０８　
　　　Ｄ　　２廊１３．ＯＲ３＝　　１４７．３９　　
　Ｄ　　３−　５．５　　　　Ｎ　　２−１．６０３１
１　　ｖ　　２−６０．７Ｒ４諺−２０９，４６０４暉
可変 ＩＩ　　５−　９３．７２　　　Ｄ　　５−　４．０　
　　　Ｎ　　３ｓ１．８０５１８　　ｖ　　３−２５．
４Ｒ６−６４４，３，：Ｉ　　　　Ｄ　　６−　１．５
　　　　　Ｎ　　４−１．４９８３１　　ν　４０６５
．０Ｉｔ　　７−　　１９．４９　　　０　７−１９．
０４Ｒ８−３１，００Ｄ　　８蓼　７．５　　　　Ｎ　
　５−１．６４２５０　　ν　５−５８．４Ｒ９諺　−
４９，３９Ｄ　　９−　０．２１ｔｌＯ−１３５，３３
０１０−１，５Ｎ　　６−１．５７０９９　　ν　６−
５０．８Ｒ１１−３５，７０Ｄｌｌ−１２，９２ＲＩ２
−　−１７．５１　　　０１２−　１．６５　　　Ｎ　
　７−１．８０５１８　　ν　７−２５．４Ｒ１３−６
５，２３０１３−６，０Ｎ　　８冒１．７７２５０　　
ν　８曽４９．６Ｒ１４−非球面　０１４−０．１５ Ｒ１５−３７７，８５０１５麿　６．８　　　　　Ｎ　
　９−１．７７２５０　　ν　９−４９．６ＲＩ６−−
２９．４４　　　　ＤＩ６−０．１５ＲＩ７−　−５２
．１８　　　０１７−　５．５　　　　Ｎｌ０−１．７
７２５０　　ｖ　１０−４９．６１８−−：１２．３０
　　ＤＩ８−可変ＲＩ９１−２０５．２４　　　０１９
−１．３　　　　　Ｎ１１−１．４８７４９　　ν　１
１露７０．２Ｒ２１■−３７８，０４ 非球面係数　　Ｒ１４ Ｒ−−３７，３８３１＾−０ ［１−１，３５５ｘ　１０−’　　Ｃ−２，８２５ｘ　
１０−’Ｄ　−−５，５３２ｘｌＰ”　　Ｅ　−５，４
８２ｘｌＯ−”数値実施例２ Ｆ　＝２］、９６　　　ＦＮｏ−１：２．８６　　　２
ω−８４，１’Ｉｔ　　ｌ−９４，３７Ｄ　　Ｉ−３，
：ｌ　　　　Ｎ　　Ｉ−１，６２２９９ν　ｌ−５８，
２Ｒ２−４０４，０４０２−０，１ Ｒ３−５１，６８０３＝　１．３　　　Ｎ　２＝１．６
９３５０　ｖ　２−５３．２Ｒ４−１８，２９０４−４
，１３ Ｒ５−３９，５２０５＝　　２．４６　　　　Ｎ　　３
−１．６４３２８　　ｖ　　３−４７．９８６−　７６
．３９　０６−可変 Ｒ７霧　　２０．４３　　　　Ｄ　　７−　０．９　　
　　　Ｎ　　４−１．６９６８０　　ν　４−５５．５
゜Ｒ８冒　　１０．３８　　　０　８−　３．７８Ｉ′
＋　９−　４９．７７　　　Ｄ　　９−　２．４４　　
　Ｎ　　５−１．８０５１８　　ν　５−２５．４ＲＩ
Ｇ−６２４，５６０ＩＧ−１，２５Ｒ１１−２１８，５
０ＤＩ＋−９，０３Ｎ　　６謬１．７５５２０　　ν　
６露２７．５１１１２■−１１１，２３０１２識　２．
６０旧３−１０１．６５　０１３−５．１５　　Ｎ　７
−１．８０４００シアー４６．６１１１４−−１９．：
１６　０１４−２．１５１１１５−−２２．０３　０１
５−３．５０　　Ｎ　８−１．８０５１８ν８−２５．
４１１１６−　４５．２２　　０１６−１．３２ＲＩ７
−−４８．７２　０１７−２．３５　　Ｎ　９−１．７
１３００シ９−５３．８１１１８−−１９．１８　　　
Ｄ１８−０．１５Ｒ１９−１０２０，：１２　　　Ｄ１
９冒　２．７　　　　　ＮＩＯ露１．７１３００　　シ
ｌＯ雪５３．８ｎ２０−−４２．２５　　Ｄ２０−可変
１１２１−４０１４．０４　　０２１冨　１．３　　　
旧ｌ■１．４８７４９　　シ１１露７０．２１１２２−
　１２８．８９　　０２２−　２．２　　　　Ｎ１２−
１．６９６８０　　ｖ　１２−５５．５１１２３−４２
８．６８ 表−１ （発明の効果） 本発明によれば所定の屈折力及びレンズ構成を有した第
１．第２．第３群のうち第２群を移動させてフォーカス
を行うインナーフォーカス方式の利点を採用しつつ無限
遠物体から近距離物体に至る物体距離全般にわたり収差
変動の少ない、特にコマ収差や非点収差の変動を良好に
補正した高い光学性能を有した逆望遠型撮影レンズを達
成することができる。R20-78, 56020-5, ON+2-1.772
50ν12-49.6F ・24.5FN
O-1: 1.45 2 (IJ-82, 9°Rl
-74,82D I-2,0N Bow, 60311
v 1-60.7 It 2- 32.08
D 2 corridor 13. OR3=147.39
D 3-5.5 N 2-1.6031
1 v 2-60.7R4 Proverbs-209,4604 暉variable II 5-93.72 D 5-4.0
N 3s1.80518 v 3-25.
4R6-644,3,:I D 6- 1.5
N 4-1.49831 ν 4065
．． 0It 7- 19.49 0 7-19.
04R8-31,00D 8 feet 7.5 N
5-1.64250 ν 5-58.4R9 proverb -
49,39D 9- 0.21tlO-135,33
010-1,5N 6-1.57099 ν 6-
50.8R11-35, 70Dll-12, 92RI2
- -17.51 012- 1.65 N
7-1.80518 ν 7-25.4R13-6
5,23013-6,0N 8-1.77250
ν 8 49.6 R14-Aspheric 014-0.15 R15-377, 85015 6.8 N
9-1.77250 ν 9-49.6RI6--
29.44 DI6-0.15RI7--52
．． 18 017-5.5 Nl0-1.7
7250 v 10-49.618--:12.30
DI8-Variable RI91-205.24 019
-1.3 N11-1.48749 ν 1
1 dew 70.2R21■-378,04 Aspheric coefficient R14 R--37,3831^-0 [1-1,355x 10-' C-2,825x
10-'D--5,532xlP"E-5,4
82xlO-” Numerical Example 2 F = 2], 96 FNo-1: 2.86 2
ω-84, 1'It l-94, 37D I-3,
:l N I-1,62299ν l-58,
2R2-404,0402-0,1 R3-51,6803=1.3 N2=1.6
9350 v 2-53.2R4-18, 2904-4
,13 R5-39,5205= 2.46 N 3
-1.64328 v 3-47.986- 76
．． 39 06-Variable R7 Fog 20.43 D 7- 0.9
N 4-1.69680 ν 4-55.5
゜R8 10.38 0 8- 3.78I'
+ 9- 49.77 D 9- 2.44
N 5-1.80518 ν 5-25.4RI
G-624,560IG-1,25R11-218,5
0DI+-9,03N 6 error 1.75520 ν
6 dew 27.51112 -111,23012 2.
60 old 3-101.65 013-5.15 N 7
-1.80400 sear 46.61114--19. :
16 014-2.151115--22.03 01
5-3.50 N 8-1.80518ν8-25.
41116- 45.22 016-1.32RI7
--48.72 017-2.35 N 9-1.7
1300shi9-53.81118--19.18
D18-0.15R19-1020,:12 D1
9 2.7 NIO Dew 1.71300 SilO Snow 53.8n20--42.25 D20-Variable 1121-4014.04 021 Tomi 1.3
Old l ■ 1.48749 Shi 11 Dew 70.21122-
128.89 022- 2.2 N12-
1.69680 v 12-55.51123-42
8.68 Table 1 (Effects of the Invention) According to the present invention, the first lens having a predetermined refractive power and lens configuration. Second. Adopting the advantages of the inner focusing method in which focusing is performed by moving the second group of the third group, it has little aberration variation over the entire object distance from infinity to close objects, and is particularly effective for coma and astigmatism. It is possible to achieve an inverted telephoto photographic lens that has high optical performance and that satisfactorily corrects fluctuations.

【図面の簡単な説明】[Brief explanation of the drawing]

第１図、第２図は各々本発明の数値実施例１゜２のレン
ズ断面図、第３図、第４図は各々本発明の数値実施例１
．２の諸収差図である。収差図において（Ａ）は無限遠
物体、（Ｂ）は至近距離物体（３０ｃｍ）での収差図で
ある。 図中、Ｉ、ｎ、ｍは各々第１．第２．第３群、ΔＳはサ
ジタル像面、ΔＭはメリディオナル像面である。 第　　　　１　　　　図 １　　　　　　　　　Ｉ［１ 弔　　　　２　　　　　ロ ４−コ ニ　　　　　　　　　　　　　　　　　　　　■■ ＤＩ　　０３　　　Ｄ５ 第　　　３　　　口（Ａ） ＦＮｏ／１４５　　　　　　ω＝４１．４５”　　　　
　ω＝４１．４５″０．４０−０．４０　　　　　　　
０．４０−３＋００　　　　　　　３．００−０°４０
輝面収芙　　　ψｌ収ｔ　　　歪曲ｕｙ、％ｃｙａ）第
　　　３　　　図　（Ｂ） ＦＮＯ／１．４５　　　　　ｂａ　＝４１，４５６　　
　　ｔＪ＝４１，４５０第　４　　図（Ａ） ＦＮＯ／２．８６　　　　　ｔａ　＝４２．０５０　　
　　Ｗ　＝　４２．０５゜−０，４０、Ｏ０！０−０．
４０　　　　　　０．４０−３．００　　　　　　３．
ｏ。 錦面収憲　　　非廊収瓜　　　歪曲択蔑□□□）ＦＮＯ
／２．８６ −Ｑ、４Ｑ　　　　　　　　　Ｑ、４０−　Ｃ工中’Ｆ
ＩＪＭヌ〉Ｅ ４　　　　図（（３）FIGS. 1 and 2 are cross-sectional views of lenses of Numerical Example 1゜2 of the present invention, and FIGS. 3 and 4 are lens cross-sectional views of Numerical Example 1 of the present invention, respectively.
．． FIG. 2 is a diagram showing various aberrations of No. 2. In the aberration diagrams, (A) is an aberration diagram for an object at infinity, and (B) is an aberration diagram for a close object (30 cm). In the figure, I, n, and m are respectively 1st. Second. In the third group, ΔS is a sagittal image plane, and ΔM is a meridional image plane. 1st Figure 1 I [1 Condolence 2 Ro4-Koni ■■ DI 03 D5 3rd mouth (A) FNo/145 ω=41.45”
ω=41.45″0.40-0.40
0.40-3+00 3.00-0°40
Bright surface convergence ψl convergence t distortion uy, %cya) Figure 3 (B) FNO/1.45 ba = 41,456
tJ = 41,450 Fig. 4 (A) FNO/2.86 ta = 42.050
W = 42.05°-0,40, O0!0-0.
40 0.40-3.00 3.
o. Nishikimen Shuken Heirou Shuurin Distortion Selection Disdain □□□) FNO
/2.86 -Q, 4Q Q, 40- C under construction'F
IJMnu〉E 4 Figure ((3)

Claims (1)

【特許請求の範囲】 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、そして正の屈折力の第３群の３つのレンズ群を有し
、前記第１群は少なくとも物体側に凸面を向けた負のメ
ニスカス状の第１１レンズと正の第１２レンズを有し、
前記第３群は負の第３１レンズと正の第３２レンズとを
貼り合わせ、このとき接合レンズ面が物体側に凸面を向
けるような形状となるような接合レンズを有し、前記第
２群を光軸上移動させることによりフォーカスを行うと
共に、前記第ｉ群の焦点距離をｆｉ、全系の焦点距離を
ｆ、前記第３群の接合レンズの接合レンズ面の屈折力を
φ３Ｂ、前記第３群の接合レンズの物体側と像面側のレ
ンズ面の曲率半径を各々Ｒ３Ａ、Ｒ３Ｃとしたとき ３．０＜｜ｆ１｜／ｆ＜１６ １．０＜ｆ２／ｆ＜１．５ ０．０３５＜｜φ３Ｂ｜・ｆ＜０．０９５ ｜Ｒ３Ｃ／Ｒ３Ａ｜＜２．０ なる条件を満足することを特徴とする逆望遠型撮影レン
ズ。[Claims] In order from the object side, the first group has negative refractive power, and the second group has positive refractive power.
and a third group with positive refractive power, the first group having at least a negative meniscus eleventh lens with a convex surface facing the object side and a positive twelfth lens. ,
The third group has a cemented lens in which a negative 31st lens and a positive 32nd lens are bonded together, and the cemented lens surface has a shape with a convex surface facing the object side. Focusing is performed by moving on the optical axis, and the focal length of the i-th group is fi, the focal length of the entire system is f, the refractive power of the cemented lens surface of the cemented lens of the third group is φ3B, and the When the radius of curvature of the object-side and image-side lens surfaces of the cemented lens of the third group is R3A and R3C, respectively, 3.0<|f1|/f<16 1.0<f2/f<1.5 0. 035<|φ3B|・f<0.095 |R3C/R3A|<2.0 A reverse telephoto photographing lens characterized by satisfying the following conditions.