JPH0416087B2 - - Google Patents
Info
- Publication number
- JPH0416087B2 JPH0416087B2 JP59161052A JP16105284A JPH0416087B2 JP H0416087 B2 JPH0416087 B2 JP H0416087B2 JP 59161052 A JP59161052 A JP 59161052A JP 16105284 A JP16105284 A JP 16105284A JP H0416087 B2 JPH0416087 B2 JP H0416087B2
- Authority
- JP
- Japan
- Prior art keywords
- lens group
- lens
- refractive power
- focusing
- moving
- 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.)
- Expired
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
- G02B15/144—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 four groups only
- G02B15/1441—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 four groups only the first group being positive
- G02B15/144105—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 four groups only the first group being positive arranged +-+-
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Lenses (AREA)
Description
本発明は屈折系と反射系を有した反射屈折式ズ
ームレンズに関し、特に反射系と屈折系との間に
配置した一部のレンズ群を移動させてフオーカシ
ングを行つた高性能な反射屈折式ズームレンズに
関するものである。
従来より反射系と屈折系を有した反射屈折式ズ
ームレンズは長焦点用のズームレンズに適してお
り各種の撮影レンズに用いられている。例えば特
公昭48−42509号公報では焦点距離500から2000ま
での望遠用の反射屈折式ズームレンズが提案され
ている。前記のズームレンズは変倍を物体側から
光の進行方向順に数えて第５番目と第６番目の２
つのレンズ群を移動させて行つている。又フオー
カシングを副鏡とズームレンズ系の前方のレンズ
群の一方若しくは双方を移動させて行つている。
しかしながら反射屈折式ズームレンズにおいて副
鏡を移動させてフオーカシングを行う方法は一般
に副鏡を移動させる為の移動機構が複雑化及び大
型化する傾向があり又前方のレンズ群を移動させ
てフオーカシングを行う方法はフオーカシングに
よる収差変動が大きくなり特に球面収差の変動が
大きくなり、全体的に収差補正を良好に行うのが
困難であつた。
本発明はフオーカシングによる収差変動の少な
い機構的に簡単でしかも高性能な反射屈折式ズー
ムレンズの提供を目的とする。
本発明の目的を達成する為の反射屈折式ズーム
レンズの主たる特徴は光の進行方向より順に屈折
系と反射系より成る正の屈折力の第１レンズ群、
前記第１レンズの屈折系と反射系との間に位置し
た負の屈折力の第２レンズ群、正の屈折力の第３
レンズ群そして第４レンズ群の４つのレンズ群を
有し、前記第３レンズ群と前記第４レンズ群を移
動させて変倍を行い前記第２レンズ群は共に負の
屈折力の第2Aレンズ群と第2Bレンズ群の２つの
レンズ群を有しており、前記第2Aレンズ群若し
くは前記第2Bレンズ群のうち少なくとも一方を
移動させてフオーカシングを行つたことである。
このように本発明においてはフオーカシングを
屈折系と反射系の中間に位置した小型の負の屈折
力の第２レンズ群を２つの負の屈折力のレンズ群
に分割し、そのうち少なくとも一方のレンズ群を
移動させて行うことにより機構的な簡素化を図り
更に、フオーカシングの際の収差変動を少なくし
ている。又第１レンズ群と第２レンズ群により望
遠型のレンズ構成とし、焦点距離を容易に長くす
ると共に後続する第３、第４レンズ群を移動させ
て変倍を行うことにより第３、第４レンズ群のレ
ンズ径を縮少しつつズームレンズ全体のコンパク
ト化を図つている。
特に本発明においてフオーカシングによる収差
変動をより少なくし、広い物体距離範囲にわたり
良好なる収差補正を達成する為には前記第１レン
ズ群、前記第2Aレンズ群そして前記第2Bレンズ
群の焦点距離を各々f〓，f〓A，f〓Bとしたとき
0.1＜｜f〓A｜／f〓＜0.4 ……(1)
0.4＜f〓A／f〓B＜2.3 ……(2)
なる条件を満足することが好ましい。
条件(1)は第１レンズ群に対する第2Aレンズ群
の屈折力を制限するものであり、第１レンズ群よ
り収束されてくる光束を無理なく屈折させ収差発
生量を少なくして第2Bレンズ群へ射出させる為
のものである。
条件(1)の下限値を越えると第2Aレンズ群の屈
折力が強くなりすぎ第2Aレンズ群若しくは第2B
レンズ群のいずれのレンズ群を移動させてフオー
カシングを行つても収差変動が大きくなるので好
ましくない。又上限値を越えると第2Aレンズ群
の屈折力が弱くなりすぎフオーカシングの際の収
差変動は少なくなるがレンズ群の移動量が多くな
りレンズ全長が長くなり又第2Aレンズ群以降の
レンズ群のレンズ外径が大きくなりズームレンズ
全体のコンパクト化を図るのが困難となる。
条件(2)は第2Aレンズ群と第2Bレンズ群の屈折
力比に関するものであり両レンズ群の屈折力を適
切に設定することによりフオーカシングの際の収
差変動、特に軸外収差の変動を良好に補正する為
のものである。
条件(2)の上限値を越えると第2Bレンズ群の屈
折力が強くなりすぎフオーカシングの際高次の収
差の発生量が多くなり特に非点収差が多く発生し
てくる。又下限値を越えて第2Bレンズ群の屈折
力が第2Aレンズ群より弱くなりすぎると第2Aレ
ンズ群からの光束が発散しすぎ画面全体にわたり
高次の収差の発生量が多くなり又第2Bレンズ群
を移動させてフオーカシングを行う場合、移動量
が多くなりすぎレンズ全長の短縮化を図るのが困
難となる。
尚本発明において第2Bレンズ群を移動させて
フオーカシングを行う場合は第2Aレンズ群を射
出する光束を略アフオーカルとするのがフオーカ
シングによる収差変動、特に球面収差の変動が少
なくなるので好ましい。
又第2Bレンズ群を負と正の屈折力のレンズを
貼り合わせた貼り合わせレンズで構成するのがフ
オーカシングの際の色収差の変動を少なくするの
に好ましい。
本発明における変倍用の第３レンズ群を物体側
より順に両レンズ面が凸面の２つの両凸レンズ、
物体側に凹面を向けた負の屈折力のメニスカス状
のレンズ、両レンズ面が凸面の両凸レンズ、両レ
ンズ面が凹面の両凹レンズそして負と正の屈折力
のレンズを貼り合わせた貼り合わせレンズで構成
し、第４レンズ群を負と正の屈折力のレンズを貼
り合わせ像画側に凸面を向け全体として負の屈折
力のメニスカス状のレンズで構成するのが変倍に
よる収差変動を少なくし、特に画面全体にわたり
コマ収差、非点収差を良好に補正するのに好まし
い。又第１レンズ群を後述する数値実施例の如く
光の進行方向より順に両レンズ面が凸面の両凸レ
ンズ、像面側に凸面を向けた裏面反射を利用した
メニスカス状の主鏡、正と負の屈折力のレンズを
貼り合わせた貼り合わせレンズそして表面反射を
利用した副鏡で構成するのが長焦点距離において
球面収差を良好に補正するのに好ましい。
以上のように本発明によればフオーカシングに
よる収差変動の少ない機構的に簡単な高性能を反
射屈折式ズームレンズを達成することができる。
次に本発明の数値実施例を示す。数値実施例に
おいてRiは物体側より光の進行順に第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
ツベ数である。
尚Diは光の進行方向左方より右方に測つた長
さを正として示してある。
フオーカシングは数値実施例１、２では第2B
レンズ群を物体側へ移動させ数値実施例３では第
2Aレンズ群を像側へ移動させて行つている。数
値実施例１、２、３において無限遠物体からフイ
ルム面より30ｍの物体までフオーカシングを行う
ときのレンズ群の移動量は各々17.199、17.482、
8.693である。
参考の為に各数値実施例の諸数値を表−１に示
す。
The present invention relates to a catadioptric zoom lens having a refractive system and a reflective system, and more particularly to a high-performance catadioptric zoom lens that performs focusing by moving some lens groups arranged between the reflective system and the refractive system. It's about lenses. Conventionally, catadioptric zoom lenses having a reflective system and a refractive system are suitable for long focal length zoom lenses and are used in various photographic lenses. For example, Japanese Patent Publication No. 48-42509 proposes a catadioptric zoom lens for telephoto use with a focal length of 500 to 2000. The above-mentioned zoom lens has two magnification changes, the fifth and sixth, counting from the object side in the order of the light traveling direction.
This is done by moving two lens groups. Focusing is also performed by moving one or both of the secondary mirror and the front lens group of the zoom lens system.
However, in the method of focusing by moving the secondary mirror in a catadioptric zoom lens, the movement mechanism for moving the secondary mirror tends to become complicated and large, and focusing is performed by moving the front lens group. With this method, aberration fluctuations due to focusing become large, especially spherical aberration fluctuations, and it is difficult to perform good aberration correction overall. SUMMARY OF THE INVENTION An object of the present invention is to provide a mechanically simple and high-performance catadioptric zoom lens with little variation in aberrations due to focusing. The main features of the catadioptric zoom lens for achieving the object of the present invention are: a first lens group with positive refractive power consisting of a refractive system and a reflective system in order from the direction of propagation of light;
A second lens group with negative refractive power located between the refractive system and the reflective system of the first lens, and a third lens group with positive refractive power.
It has four lens groups, a lens group and a fourth lens group, and the third lens group and the fourth lens group are moved to change the magnification, and the second lens group both includes a 2A lens having a negative refractive power. It has two lens groups, a lens group and a 2B lens group, and focusing is performed by moving at least one of the 2A lens group or the 2B lens group. In this way, in the present invention, focusing is performed by dividing the small second lens group with negative refractive power located between the refractive system and the reflective system into two lens groups with negative refractive power, and at least one of the lens groups By moving the lens, the mechanism is simplified, and aberration fluctuations during focusing are reduced. In addition, the first lens group and the second lens group form a telephoto lens structure, and the focal length can be easily increased, and the following third and fourth lens groups can be moved to change the magnification. The aim is to make the entire zoom lens more compact by reducing the lens diameter of the lens group. In particular, in the present invention, in order to further reduce aberration fluctuations due to focusing and achieve good aberration correction over a wide object distance range, the focal lengths of the first lens group, the 2A lens group, and the 2B lens group must be adjusted. When f〓, f〓 A , f〓 B , 0.1＜｜f〓 A ｜／f〓＜0.4 ...(1) 0.4＜f〓 A /f〓 B ＜2.3 ...(2) Satisfies the following conditions It is preferable to do so. Condition (1) limits the refractive power of the 2A lens group with respect to the 1st lens group, and allows the light beam converged from the 1st lens group to be refracted without difficulty, reducing the amount of aberration generated, and refracting the 2B lens group. It is for ejecting to. If the lower limit of condition (1) is exceeded, the refractive power of the 2A lens group becomes too strong and the 2A lens group or the 2B lens group becomes too strong.
It is not preferable to move any of the lens groups to perform focusing because the aberration fluctuations will increase. If the upper limit is exceeded, the refractive power of the 2A lens group will become too weak, and aberration fluctuations during focusing will be reduced, but the amount of movement of the lens group will increase, resulting in a longer lens overall length. The outer diameter of the lens increases, making it difficult to make the entire zoom lens compact. Condition (2) concerns the refractive power ratio of the 2A lens group and the 2B lens group, and by appropriately setting the refractive powers of both lens groups, aberration fluctuations during focusing, especially off-axis aberration fluctuations, can be suppressed. This is to correct for. If the upper limit of condition (2) is exceeded, the refractive power of the 2B lens group becomes too strong, resulting in a large amount of higher-order aberrations occurring during focusing, and in particular, a large amount of astigmatism. If the lower limit is exceeded and the refractive power of the 2B lens group becomes too weak than that of the 2A lens group, the luminous flux from the 2A lens group will diverge too much and a large amount of higher-order aberrations will occur over the entire screen. When focusing is performed by moving the lens group, the amount of movement becomes too large, making it difficult to shorten the overall length of the lens. In the present invention, when focusing is performed by moving the 2B lens group, it is preferable to make the light beam exiting the 2A lens group approximately afocal, since this reduces aberration fluctuations, especially spherical aberration fluctuations, due to focusing. Further, it is preferable to configure the second B lens group with a composite lens in which lenses with negative and positive refractive powers are bonded together, in order to reduce fluctuations in chromatic aberration during focusing. The third lens group for variable magnification in the present invention includes, in order from the object side, two biconvex lenses whose both lens surfaces are convex,
A meniscus lens with negative refractive power with the concave surface facing the object, a biconvex lens with convex surfaces on both surfaces, a biconcave lens with concave surfaces on both surfaces, and a composite lens with negative and positive refractive powers bonded together. The fourth lens group is composed of a meniscus-shaped lens with a negative refractive power and a convex surface facing the image side, which is a combination of lenses with negative and positive refractive powers, which reduces aberration fluctuations due to zooming. However, it is particularly preferable for correcting coma aberration and astigmatism well over the entire screen. In addition, as shown in the numerical examples described below, the first lens group includes a biconvex lens in which both lens surfaces are convex in order from the direction of light propagation, a meniscus-shaped primary mirror that uses back reflection with the convex surface facing the image plane, and positive and negative lenses. In order to satisfactorily correct spherical aberration at a long focal length, it is preferable to construct the lens with a bonded lens made of lenses having a refractive power of As described above, according to the present invention, it is possible to achieve a mechanically simple, high-performance catadioptric zoom lens with little variation in aberrations due to focusing. 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 from the object side in the order of propagation of light, Di is the i-th lens thickness and air distance from the object side, and Ni and νi are the i-th lens surfaces in order from the object side. are the refractive index and Atsube number of the lens glass. Note that Di indicates the length measured from the left to the right in the direction of light propagation as positive. Focusing is 2B in numerical examples 1 and 2.
In Numerical Example 3, the lens group is moved to the object side.
This is done by moving the 2A lens group towards the image side. In Numerical Examples 1, 2, and 3, the amount of movement of the lens group when focusing from an object at infinity to an object 30 m from the film surface is 17.199, 17.482, respectively.
It is 8.693. For reference, various numerical values of each numerical example are shown in Table-1.
【表】
〓 〓
[Table] 〓 〓
【表】【table】
【表】
〓 〓
[Table] 〓 〓
【表】【table】
【表】
〓 〓
[Table] 〓 〓
【表】【table】
第１、第２、第３図は各々本発明の数値実施例
１〜３のレンズ断面図、第４−Ａ，Ｂ図、第６−
Ａ，Ｂ図、第８−Ａ，Ｂ図は各々本発明の数値実
施例１〜３の無限遠物体のときの諸収差図、第５
−Ａ，Ｂ図、第７−Ａ，Ｂ図、第９−Ａ，Ｂ図は
各々本発明の数値実施例１〜３の物体距離30ｍ
（フイルム面より）のときの諸収差図である。図
中Ａは広角端、Ｂは望遠端での諸収差図、Ｙは像
高、ｄはｄ線、S.Cは正弦条件、Ｓはサジタル像
面、Ｍはメリデイオナル像面、，，Ａ，
Ｂ，，は各々第１、第２、第2A、第2B、第
３、第４レンズ群である。
Figures 1, 2, and 3 are lens sectional views of numerical examples 1 to 3 of the present invention, Figures 4-A and B, and 6-
Figures A, B and 8-A and B are various aberration diagrams for an object at infinity in numerical embodiments 1 to 3 of the present invention, and Figure 5
Figures -A and B, Figures 7-A and B, and Figures 9-A and B are for numerical examples 1 to 3 of the present invention at an object distance of 30 m.
(From the film surface) Various aberration diagrams. In the figure, A is a diagram of various aberrations at the wide-angle end, B is a diagram of various aberrations at the telephoto end, Y is the image height, d is the d-line, SC is the sine condition, S is the sagittal image plane, M is the meridional image plane, ,,A,
B, , are the first, second, 2A, 2B, third, and fourth lens groups, respectively.
Claims (1)
る正の屈折力の第１レンズ群、前記第１レンズの
屈折系と反射系との間に位置した負の屈折力の第
２レンズ群、正の屈折力の第３レンズ群そして第
４レンズ群の４つのレンズ群を有し、前記第３レ
ンズ群と前記第４レンズ群を移動させて変倍を行
い前記第２レンズ群は共に負の屈折力の第2Aレ
ンズ群と第2Bレンズ群の２つのレンズ群を有し
ており、前記第2Aレンズ群若しくは前記第2Bレ
ンズ群のうち少なくとも一方を移動させてフオー
カシングを行い、そして前記第１レンズ群、前記
第2Aレンズ群そして前記第2Bレンズ群の焦点距
離を各々f〓，f〓A，f〓Bとしたとき 0.1＜｜f〓A｜／f〓＜0.4 0.4＜f〓A／f〓B＜2.3 なる条件を満足することを特徴とする反射屈折式
ズームレンズ。[Claims] 1. A first lens group with positive refractive power consisting of a refractive system and a reflective system in order from the direction of travel of light, and a negative refractive power located between the refractive system and the reflective system of the first lens. It has four lens groups: a second lens group with positive refractive power, a third lens group with positive refractive power, and a fourth lens group, and the third lens group and the fourth lens group are moved to change the magnification. The second lens group has two lens groups, a 2A lens group and a 2B lens group, both of which have negative refractive power, and focusing is performed by moving at least one of the 2A lens group or the 2B lens group. and when the focal lengths of the first lens group, the second A lens group, and the second B lens group are f〓, f〓 A , f〓 B , respectively, 0.1<|f〓 A |/f〓< A catadioptric zoom lens characterized by satisfying the following condition: 0.4 0.4<f〓 A /f〓 B <2.3.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP16105284A JPS6139015A (en) | 1984-07-31 | 1984-07-31 | Reflecting/refracting type zoom lens |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP16105284A JPS6139015A (en) | 1984-07-31 | 1984-07-31 | Reflecting/refracting type zoom lens |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6139015A JPS6139015A (en) | 1986-02-25 |
| JPH0416087B2 true JPH0416087B2 (en) | 1992-03-23 |
Family
ID=15727691
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP16105284A Granted JPS6139015A (en) | 1984-07-31 | 1984-07-31 | Reflecting/refracting type zoom lens |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6139015A (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5331467A (en) * | 1991-02-25 | 1994-07-19 | Nikon Corporation | Reflex lens system having the antivibration function |
| JP4753615B2 (en) * | 2005-04-28 | 2011-08-24 | 花王株式会社 | Mascara makeup tools |
| JP4775960B2 (en) * | 2006-09-20 | 2011-09-21 | 株式会社新和製作所 | Cosmetic applicator |
| KR101362767B1 (en) * | 2007-11-02 | 2014-02-13 | 삼성전자주식회사 | Telephoto lens system |
| JP2013218022A (en) | 2012-04-05 | 2013-10-24 | Olympus Imaging Corp | Reflection telephoto optical system, optical unit, and imaging apparatus having the same |
| JP7026933B2 (en) * | 2017-11-14 | 2022-03-01 | 株式会社nittoh | Imaging optical system and imaging device |
-
1984
- 1984-07-31 JP JP16105284A patent/JPS6139015A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6139015A (en) | 1986-02-25 |
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