JPH0358088B2 - - Google Patents
Info
- Publication number
- JPH0358088B2 JPH0358088B2 JP57018901A JP1890182A JPH0358088B2 JP H0358088 B2 JPH0358088 B2 JP H0358088B2 JP 57018901 A JP57018901 A JP 57018901A JP 1890182 A JP1890182 A JP 1890182A JP H0358088 B2 JPH0358088 B2 JP H0358088B2
- Authority
- JP
- Japan
- Prior art keywords
- lens group
- lens
- focal length
- distance
- zoom
- 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
- 230000003287 optical effect Effects 0.000 claims description 2
- 230000004075 alteration Effects 0.000 description 7
- 238000010586 diagram Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 2
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000011514 reflex Effects 0.000 description 1
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
-
- 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
- G02B15/143—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 three groups only
- G02B15/1431—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 three groups only the first group being positive
- G02B15/143103—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 three groups only the first group being positive arranged ++-
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Nonlinear Science (AREA)
- Lenses (AREA)
Description
本発明は、特にレンジフアインダカメラのよう
に携帯性が問題となるカメラに適した小型のズー
ムレンズに関する。
レンジフアインダカメラの普及に伴つて、ズー
ムレンズを装着したレンジフアインダカメラへの
要望が高まつてきている。しかし、レンジフアイ
ンダカメラは携帯性が問題であり、従来の１眼レ
フカメラ用のズームレンズはコンパクト性に問題
があつた。
すなわち、従来のズームレンズにおいては、正
レンズ群と負レンズ群の組合せで変倍を行うもの
が多いが、ズームレンズ系に変倍のための負のレ
ンズ群を含むことはレンズ系の全長を短かくする
のには不利であつた。
本発明は、２つの正の焦点距離を有するレンズ
群の間隔を変化させて変倍を行うことにより、レ
ンズ系の像側主点を第１レンズ群近傍に維持し、
第１レンズ群から像画までの距離を、レンズ全系
の焦点距離に近い長さとすることが出来、小型の
ズームレンズを得ることが出来た。
すなわち、ズームレンズは３レンズ群によつて
構成されるものとし、第１レンズ群の焦点距離を
f1、第２レンズ群の焦点距離をf2、第３レンズ群
の焦点距離をf3とし、第１レンズ群と第２レンズ
群の主点間距離をt1、第２レンズ群と第３レンズ
群の主点間距離をt2、第３レンズ群の像側点主か
ら像画までの距離をfBとすると、全系の合成焦点
距離ｆは
ｆ＝f1×f2／f1＋f2−t1・f3−fB／f3
またt2は
t2＝（f1−t1）・f2／f1＋f2−t1−f3・fB／f3
−fB
で与えられる。
変倍は２つの正レンズ群の間隔を変化させるこ
とによつて行なわれ、このズームレンズ系の変倍
比をＭとすると
Ｍf1＋f2／f2
でほぼ近似できる。
すなわち、第２レンズ群の焦点距離f2を小さく
する程度倍比を大きくすることが可能になる。
しかし、本発明の実施例のように、広角端の画
角が57度に及び、変倍比を1.5倍程度とろうとす
れば、第２レンズ群の焦点距離f2をかなり小さく
とらざるを得なくなる。したがつて、第２レンズ
群の移動による収差の変動、特に望遠側での像面
湾曲のアンダー化が顕著となる。これを補正する
ために、第２レンズ群とほぼ同程度の焦点距離を
持つ負の第３レンズ群を像面近傍に固定配置し
た。
上記のように、本発明のズームレンズは、物体
側から順に正の焦点距離を有する第１レンズ群、
同じく正の焦点距離を有する第２レンズ群、及び
負の焦点距離を有する第３レンズ群の３群によつ
て構成され、変倍時、前記第１レンズ群は変倍に
よる焦点移動の補正のために、また、第２レンズ
群は変倍のために、第１レンズと第２レンズ群の
間隔及び第２レンズ群と第３レンズ群の間隔がそ
れぞれ変化するようにそれぞれ独立に光軸方向に
移動する一方、第３レンズ群は像面近傍に固定さ
れている。
そして、次の条件を満すことが望ましい。
−3f2＜f3＜１／３f2 ……(1)
１／３f1＜f2＜3f1 ……(2)
Ｕ＜fB＜１／２f1 ……(3)
条件(1)は、負の第３レンズ群の持つ前記の像面
湾曲の補正効果を得るための条件で、上限を越え
ると像画が補正過剰となり、下限を越えると像画
の補正作用が不足する。
条件(2)は変倍による収差変動を抑えるための条
件である。変倍は第１レンズ群と第２レンズ群を
移動させることによつて行なうが、収差補正は第
１レンズ群が主に分担しており、第１レンズ群に
比べ第２レンズ群の焦点距離が短くなりすぎる
と、変倍による収差変動が補正し切れなくなる。
条件(2)の上限を越えると（）式から明らかなよ
うに充分な変倍比を得ることが困難になる。また
下限を越えると第２レンズ群の発生する収差を第
１レンズ群で補正することが困難になる。
条件(3)は第３レンズ群の位置に関する条件であ
り、バツクフオーカスfBが零より大きいことは、
実像をフイルム面上に作るための必要条件であ
る。上限を越えると、第２レンズ群が変倍のため
に移動できる範囲が制限され、充分な変倍比をと
ることが困難となる。
以下、本発明のズームレンズの実施例を示す。
レンズ各群の移動径路を第１図に、実施例１のレ
ンズ断面を第２図に、実施例２のレンズ断面を第
３図に示す。第４図、第５図はそれぞれの実施例
の収差図である。
実施例 １
The present invention relates to a compact zoom lens particularly suitable for cameras where portability is an issue, such as rangefinder cameras. With the spread of rangefinder cameras, the demand for rangefinder cameras equipped with zoom lenses has increased. However, rangefinder cameras have problems with portability, and conventional zoom lenses for single-lens reflex cameras have problems with compactness. In other words, in many conventional zoom lenses, zooming is performed by a combination of a positive lens group and a negative lens group, but including a negative lens group for zooming in a zoom lens system reduces the overall length of the lens system. It was disadvantageous to make it shorter. The present invention maintains the image-side principal point of the lens system near the first lens group by changing the distance between two lens groups having positive focal lengths to change the magnification.
The distance from the first lens group to the image could be made close to the focal length of the entire lens system, and a compact zoom lens could be obtained. In other words, the zoom lens is composed of three lens groups, and the focal length of the first lens group is
f 1 , the focal length of the second lens group is f 2 , the focal length of the third lens group is f 3 , the distance between the principal points of the first lens group and the second lens group is t 1 , the distance between the principal points of the second lens group and the If the distance between the principal points of the three lens groups is t 2 and the distance from the image side point principal of the third lens group to the image is f B , the combined focal length f of the entire system is f = f 1 × f 2 /f 1 +f 2 −t 1・f 3 −f B ／f 3 and t 2 is t 2 = (f 1 − t 1 )・f 2 /f 1 +f 2 −t 1 −f 3・f B ／f 3
−f is given by B. The magnification is changed by changing the distance between two positive lens groups, and if the magnification ratio of this zoom lens system is M, it can be approximately approximated by Mf 1 +f 2 /f 2 . That is, it becomes possible to increase the magnification ratio by decreasing the focal length f 2 of the second lens group. However, as in the embodiment of the present invention, if the angle of view at the wide-angle end is 57 degrees and the variable power ratio is about 1.5 times, the focal length f2 of the second lens group must be made quite small. It disappears. Therefore, fluctuations in aberrations due to movement of the second lens group, especially under-curvature of field on the telephoto side, become noticeable. In order to correct this, a negative third lens group having approximately the same focal length as the second lens group is fixedly arranged near the image plane. As described above, the zoom lens of the present invention includes, in order from the object side, a first lens group having a positive focal length,
It is also composed of three lens groups: a second lens group having a positive focal length and a third lens group having a negative focal length. In order to change the magnification, the second lens group is adjusted in the optical axis direction independently so that the distance between the first lens group and the second lens group and the distance between the second lens group and the third lens group change respectively. , while the third lens group is fixed near the image plane. It is desirable that the following conditions be satisfied. −3f 2 <f 3 <1/3f 2 ...(1) 1/3f 1 <f 2 <3f 1 ...(2) U<f B <1/2f 1 ...(3) Condition (1) is , is a condition for obtaining the above-mentioned field curvature correction effect of the negative third lens group, and if the upper limit is exceeded, the image will be over-corrected, and if the lower limit is exceeded, the image will not have an insufficient correction effect. Condition (2) is a condition for suppressing aberration fluctuations due to zooming. Zooming is performed by moving the first and second lens groups, but aberration correction is mainly done by the first lens group, and the focal length of the second lens group is smaller than that of the first lens group. If becomes too short, aberration fluctuations due to zooming cannot be corrected completely.
If the upper limit of condition (2) is exceeded, it becomes difficult to obtain a sufficient zoom ratio, as is clear from equation (). If the lower limit is exceeded, it becomes difficult for the first lens group to correct the aberrations generated by the second lens group. Condition (3) is a condition regarding the position of the third lens group, and the fact that the back focus f B is greater than zero means that
This is a necessary condition for creating a real image on the film surface. If the upper limit is exceeded, the range in which the second lens group can move for zooming is limited, making it difficult to obtain a sufficient zoom ratio. Examples of the zoom lens of the present invention will be shown below.
FIG. 1 shows the movement path of each lens group, FIG. 2 shows a cross section of the lens of Example 1, and FIG. 3 shows a cross section of the lens of Example 2. FIGS. 4 and 5 are aberration diagrams of each example. Example 1
【表】【table】
【表】 実施例 ２【table】 Example 2
第１図は本発明のズームレンズの各レンズ群の
移動径路図、第２図、第３図はそれぞれ実施例
１、実施例２のレンズ断面図、第４図、第５図は
それぞれの実施例の収差曲線図である。
FIG. 1 is a movement path diagram of each lens group of the zoom lens of the present invention, FIGS. 2 and 3 are cross-sectional views of lenses of Example 1 and Example 2, respectively, and FIGS. 4 and 5 are illustrations of respective implementations. FIG. 3 is an example aberration curve diagram.
Claims (1)
レンズ群、正の焦点距離を有する第２レンズ群及
び負の焦点距離を有する第３レンズ群によつて構
成され、変倍時、第１レンズ群と第２レンズ群の
間隔及び第２レンズ群と第３レンズ群の間隔がそ
れぞれ変化するように、前記第１レンズ群及び第
２レンズ群はそれぞれ独立に光軸方向に移動し、
その間、第３レンズ群は像面に対して固定されて
いることを特徴とする小型ズームレンズ。1. In order from the object side, the first
It is composed of a lens group, a second lens group having a positive focal length, and a third lens group having a negative focal length, and when changing magnification, the distance between the first lens group and the second lens group and the second lens group The first lens group and the second lens group each independently move in the optical axis direction so that the distance between the first lens group and the third lens group changes,
A small zoom lens characterized in that the third lens group is fixed with respect to the image plane.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP57018901A JPS58137813A (en) | 1982-02-10 | 1982-02-10 | Small-sized zoom lens |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP57018901A JPS58137813A (en) | 1982-02-10 | 1982-02-10 | Small-sized zoom lens |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS58137813A JPS58137813A (en) | 1983-08-16 |
| JPH0358088B2 true JPH0358088B2 (en) | 1991-09-04 |
Family
ID=11984481
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP57018901A Granted JPS58137813A (en) | 1982-02-10 | 1982-02-10 | Small-sized zoom lens |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS58137813A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20220011545A1 (en) * | 2020-07-13 | 2022-01-13 | Aac Optics (Changzhou) Co., Ltd. | Camera optical lens |
Families Citing this family (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4701033A (en) * | 1983-09-09 | 1987-10-20 | Minolta Camera Kabushiki Kaisha | Variable focal length lens system |
| US4822152A (en) * | 1986-08-11 | 1989-04-18 | Olympus Optical Co., Ltd. | Compact high-vari-focal ratio zoom lens system |
| JPH083580B2 (en) * | 1986-12-18 | 1996-01-17 | オリンパス光学工業株式会社 | Compact high-magnification zoom lens |
| JP2619632B2 (en) * | 1986-12-25 | 1997-06-11 | オリンパス光学工業株式会社 | Compact high-magnification zoom lens |
| US4854682A (en) * | 1987-11-13 | 1989-08-08 | Olympus Optical Co., Ltd. | Compact high vari-focal ratio zoom lens system |
| JP2798090B2 (en) * | 1988-02-10 | 1998-09-17 | オリンパス光学工業株式会社 | Focusing method of zoom lens |
| US4818082A (en) * | 1988-05-27 | 1989-04-04 | Eastman Kodak Company | Compact wide-angle close-focus SLR zoom lens |
| US5327290A (en) * | 1989-10-13 | 1994-07-05 | Minolta Camera Kabushiki Kaisha | Compact size zoom lens system |
| US5283693A (en) * | 1990-06-13 | 1994-02-01 | Minolta Camera Kabushiki Kaisha | Compact zoom lens system |
| US5424870A (en) * | 1990-07-20 | 1995-06-13 | Minolta Camera Kabushiki Kaisha | Compact zoom lens system |
| JP3260798B2 (en) * | 1991-03-04 | 2002-02-25 | オリンパス光学工業株式会社 | Wide-angle zoom lens |
| JP5975386B2 (en) * | 2012-08-17 | 2016-08-23 | 株式会社オプトロジック | Imaging lens |
| JP6341442B2 (en) * | 2014-01-28 | 2018-06-20 | 株式会社リコー | Image reading lens, image reading apparatus, and image forming apparatus |
| TWI507723B (en) | 2014-08-01 | 2015-11-11 | Largan Precision Co Ltd | Imaging optical lens group, image capturing device and electronic device |
| JP7289711B2 (en) * | 2019-04-25 | 2023-06-12 | キヤノン株式会社 | Optical system and imaging device having the same |
-
1982
- 1982-02-10 JP JP57018901A patent/JPS58137813A/en active Granted
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20220011545A1 (en) * | 2020-07-13 | 2022-01-13 | Aac Optics (Changzhou) Co., Ltd. | Camera optical lens |
| US11892596B2 (en) * | 2020-07-13 | 2024-02-06 | Aac Optics (Changzhou) Co., Ltd. | Camera optical lens |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS58137813A (en) | 1983-08-16 |
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