JPH0436714A - Retrofocus type photographic lens - Google Patents
Retrofocus type photographic lensInfo
- Publication number
- JPH0436714A JPH0436714A JP2141340A JP14134090A JPH0436714A JP H0436714 A JPH0436714 A JP H0436714A JP 2141340 A JP2141340 A JP 2141340A JP 14134090 A JP14134090 A JP 14134090A JP H0436714 A JPH0436714 A JP H0436714A
- Authority
- JP
- Japan
- Prior art keywords
- lens
- lenses
- positive
- retrofocus type
- back focus
- 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.)
- Pending
Links
- 230000005499 meniscus Effects 0.000 claims abstract description 3
- 230000004075 alteration Effects 0.000 abstract description 13
- 210000001747 pupil Anatomy 0.000 description 7
- 238000003384 imaging method Methods 0.000 description 5
- 230000003287 optical effect Effects 0.000 description 4
- 239000011521 glass Substances 0.000 description 3
- 206010010071 Coma Diseases 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- 201000009310 astigmatism Diseases 0.000 description 1
- 239000006059 cover glass Substances 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 230000011514 reflex Effects 0.000 description 1
Landscapes
- Lenses (AREA)
Abstract
Description
【発明の詳細な説明】
（産業上の利用分野）
この発明は、バックフォーカスが長い撮影レンズ、特に
ビデオカメラ、スチルビデオカメラ用として好適な撮影
レンズに関する。DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a photographic lens with a long back focus, particularly to a photographic lens suitable for use in video cameras and still video cameras.
（従来技術）
一般に、ビデオカメラ、スチルビデオカメラにおいては
、レンズ系と撮像素子の間に、光の高周波成分をカット
するためのローパスフィルターや、色分解系の光学部材
を配置することが多く、そのための空間を確保するため
に、撮影レンズは長いバックフォーカスを必要とする。(Prior Art) Generally, in video cameras and still video cameras, a low-pass filter for cutting high frequency components of light and color separation optical members are often placed between the lens system and the image sensor. In order to secure the space for this purpose, the photographic lens requires a long back focus.
また、撮像素子の前方に色分解系としてストライプフィ
ルターあるいは、モザイクフィルター等を配置する場合
には、撮影レンズ系の最終面から射出され上記フィルタ
ーに入射する光束の主光線と、レンズ系の光軸とのなす
角度が、像高に依存せずになる式く小さいこと、すなわ
ち、テレセントリック性が良好であることが色にじみを
防ぐ上で重要である。In addition, when placing a stripe filter or mosaic filter as a color separation system in front of the image sensor, the principal ray of the light beam emitted from the final surface of the photographic lens system and incident on the filter, and the optical axis of the lens system In order to prevent color fringing, it is important that the angle formed between the two images is small enough to be independent of the image height, that is, the telecentricity is good.
負、正、負、正、正の５枚のレンズで構成され、バック
フォーカスが十分に長い撮影レンズ系は、例えば、特開
平１−２２１７１４号公報、特開昭６４−６１７１４号
公報、特開昭６０−２６９１９号公報等に見られる。Photographic lens systems that are composed of five lenses (negative, positive, negative, positive, and positive) and have a sufficiently long back focus are disclosed in, for example, Japanese Patent Application Laid-Open No. 1-221714, Japanese Patent Application Laid-open No. 64-61714, and Japanese Patent Application Laid-Open No. 64-61714. This can be found in Publication No. 60-26919, etc.
しかし、特開平１−２２１７１４号公報記載のもの、及
び特開昭６０−２６９１９号公報記載のものは、撮影画
角（２ω）が３９°〜４０’程度と狭く、本発明の撮影
レンズと同様の目的には使用することが８米ない。However, the lenses described in JP-A-1-221714 and JP-A-60-26919 have a narrow shooting angle of view (2ω) of about 39° to 40', similar to the shooting lens of the present invention. There is no use for this purpose.
また、特開昭６４−６１７１４号公報記載のものは、−
眼レフ式スチルビデオカメラ用の撮影レンズであり、全
系の焦点距離の２〜２．５倍という非常に長いバックフ
ォーカスを得るために、レンズ全系も長いタイプとなり
、コンパクト性に欠けるものである。Moreover, the one described in JP-A No. 64-61714 is -
This is a photographic lens for an eye reflex still video camera, and in order to obtain a very long back focus of 2 to 2.5 times the focal length of the entire lens system, the entire lens system is also long, making it less compact. be.
（この発明が解決しようとする問題点）この発明は、Ｆ
ナンバー２．８、撮影画角（２ω）が４５°〜４８°程
度であり、バックフォーカスが十分に長く、しかも、各
射出光束の主光線と光軸とのなす角度が小さい、収差補
正の良好になされたレンズ系を実現しようとするもので
ある。(Problem to be solved by this invention) This invention is based on F.
Number 2.8, the shooting angle of view (2ω) is approximately 45° to 48°, the back focus is sufficiently long, and the angle between the principal ray of each emitted light beam and the optical axis is small, and aberration correction is good. This is an attempt to realize a lens system that was previously developed.
（問題を解決するための手段）
この発明のレンズ系は、物体側より順に、第１レンズは
物体側に凸面を向けた負メニスカスレンズ、第２レンズ
は両凸レンズ、第３レンズは両凹レンズ、第４レンズは
像側に強い凸面を向けた正レンズ、第５レンズは正レン
ズの５枚レンズより構成され、絞りが第１レンズの前方
に配置されたレトロフォーカス型の撮影レンズであり、
次の各条件を満足する。(Means for Solving the Problem) The lens system of the present invention includes, in order from the object side, the first lens is a negative meniscus lens with a convex surface facing the object side, the second lens is a biconvex lens, the third lens is a biconcave lens, The fourth lens is a positive lens with a strongly convex surface facing the image side, and the fifth lens is a retrofocus type photographic lens consisting of five lenses, with the aperture located in front of the first lens.
Satisfy each of the following conditions.
（１） ２．２ ＜｜ｆ１／ｆ２｜＜３．８（２）
０．０８＜ｄ２／ｌ ｆ、ｌ＜０．１８ただし、
ｆｌ：第１レンズの焦点距離
ｆ２：第２レンズの焦点距離
ｄ２：第１レンズと第２レンズの間の空気間隔を示す。(1) 2.2 <|f1/f2|<3.8(2)
0.08<d2/l f, l<0.18 However, fl: Focal length of the first lens f2: Focal length of the second lens d2: Indicates the air gap between the first lens and the second lens.
更に副次的には、 （３） ｎ２＞ １．７５ （４） ｄ、 ＜ ｄ。Furthermore, secondarily, (3) n2> 1.75 (4) d, < d.
（５） ν１ 〉 ５０ を満たすことが望ましい。(5) ν1 50 It is desirable to satisfy the following.
ただし、
ｎ２：第２レンズの屈折率
ｄ６：第３レンズと第４レンズの間の空気間隔ｄ７：第
４レンズの軸上厚
ｙ□：第１レンズのアツベ数
を示す。However, n2: refractive index of the second lens d6: air distance between the third lens and the fourth lens d7: axial thickness of the fourth lens y□: represents the Atsube number of the first lens.
（作用）
この発明のレンズ系では、第１レンズを負レンズとし、
正のパワーをもつ第４レンズを像側に強い凸面を向けた
レンズとすることにより、バックフォーカスの長いレン
ズ系を実現している。(Function) In the lens system of the present invention, the first lens is a negative lens,
By using the fourth lens with positive power as a lens with a strongly convex surface facing the image side, a lens system with a long back focus is realized.
また、絞りを第１レンズの前方に配置することにより、
結像面から射出瞳までの距離が長くとれることになり、
結果的にレンズ系の最終面から射出する各光束の主光線
と光軸とのなす角度が小さくなり、ビデオカメラやスチ
ルビデオカメラに好適となると同時に、製造時には、５
枚のレンズを順次、レンズ枠に落とし込んでいけばよい
ので、コストダウンにもつながる。Also, by placing the aperture in front of the first lens,
This allows for a longer distance from the imaging plane to the exit pupil,
As a result, the angle between the principal ray of each light beam emerging from the final surface of the lens system and the optical axis becomes smaller, making it suitable for video cameras and still video cameras.
Since all the lenses need to be placed one after another into the lens frame, it also leads to cost reductions.
以下、各条件式について説明する。Each conditional expression will be explained below.
十分なバックフォーカスを得るためには、第１レンズの
負の屈折力を強くしなければならず、そのためには、条
件式（１）の上限を越えないようにしなければならない
。逆に条件式（１）の下限を越えると、第１レンズで発
生した正の球面収差を第２レンズで補正することができ
なくなり、球面収差が補正過剰となる。In order to obtain sufficient back focus, the negative refractive power of the first lens must be made strong, and for this purpose, the upper limit of conditional expression (1) must not be exceeded. Conversely, if the lower limit of conditional expression (1) is exceeded, the positive spherical aberration generated by the first lens cannot be corrected by the second lens, and the spherical aberration becomes overcorrected.
条件式（２）の下限を越えると、バックフォーカスが不
足し、逆に上限を越えると、バックフォーカスは十分と
なるが、第２レンズの径が大きくなり、また、コマ収差
の補正が困難になる。If the lower limit of conditional expression (2) is exceeded, the back focus will be insufficient; if the upper limit is exceeded, the back focus will be sufficient, but the diameter of the second lens will become large, and it will be difficult to correct coma aberration. Become.
また、第２レンズは、前述のように、球面収差を良好に
補正するために比較的強い屈折力を有することが必要で
あるが、条件式（３）の下限を越えて、第２レンズの屈
折率が小さくなると、第２レンズの曲率がきつくなり、
コマ収差を良好に保つことが困難になる。Furthermore, as mentioned above, the second lens needs to have a relatively strong refractive power in order to satisfactorily correct spherical aberration, but if the lower limit of conditional expression (3) is exceeded, the second lens As the refractive index decreases, the curvature of the second lens becomes tighter,
It becomes difficult to maintain good coma aberration.
条件式（４）は非点収差の補正のためのものであり、強
度の発散作用を受ける第３レンズと第４レンズの間の空
気間隔ｄ、を第４レンズの軸上厚ｄ７より小さくするこ
とにより、良好な補正がなされるものである。Conditional expression (4) is for correcting astigmatism, and the air distance d between the third lens and the fourth lens, which is subject to a strong diverging effect, is made smaller than the axial thickness d7 of the fourth lens. This allows for good correction.
条件式（５）は第１レンズでの色収差の発生を抑えるも
のであり、この条件を越えた場合には。Conditional expression (5) suppresses the occurrence of chromatic aberration in the first lens, and if this condition is exceeded.
特に、軸上の色収差がオーバーとなる。In particular, axial chromatic aberration becomes excessive.
（実施例） 以下にこの発明の撮影レンズの実施例を示す。(Example) Examples of the photographic lens of the present invention will be shown below.
ここでｆは全系の焦点距離、ｒはレンズ各面の曲率半径
、ｄはレンズ厚またはレンズ間隔、ｎは屈折率、γ、は
アツベ数、２ωは画角、ＦはＦナンバーを示す。また、
レンズ系の像側にカバーガラスを装着しており、これを
共に示す。Here, f is the focal length of the entire system, r is the radius of curvature of each lens surface, d is the lens thickness or lens spacing, n is the refractive index, γ is the Abbe number, 2ω is the angle of view, and F is the F number. Also,
A cover glass is attached to the image side of the lens system, which is also shown.
実施例１
ｆ＝１０ ２０＝４７６４２’ Ｆ＝２．８ｒ
ｄ ｎ Ｖｄ
ｌ １３．０６６ ０．７０ １．．５１．
６３３ ６４．１２４゜８８４ ２．００
３ ６．６６２ ３．３０ １．８３４００
３７．２４ −６．７５９ ０．５
０５ −５．１０２ ０．７０ １．８
４６６６ ２３．８６ ９．０６３
１．００７ −３０．２１１ ３．００
１．７７２５０ ４９．６８ −６
．６５０ ０．２０９ ５７．３４１
２．２０ １．６９６８０ ５５．５１．０
−２１．８５８ ２．００１１ カバー
（Ｘ） ４．８４ １．５１６３３ ６４．１１
２ ガラス ω
ｆ工／Ｌｌ＝３．４４ ｄ２／１ｆ１１＝０．１３結
像面から射出瞳までの距Ｉｔ ： ＋８７１．９ａｎ
（結像面から見て、射出瞳は物体と反対の方向にある。Example 1 f=10 20=47642' F=2.8r
d n Vd l 13.066 0.70 1. ．． 51.
633 64.124°884 2.00 3 6.662 3.30 1.83400
37.24 -6.759 0.5
05 -5.102 0.70 1.8
4666 23.86 9.063
1.007 -30.211 3.00
1.77250 49.68 -6
．． 650 0.209 57.341
2.20 1.69680 55.51.0
-21.858 2.0011 Cover
(X) 4.84 1.51633 64.11
2 Glass ω f/Ll=3.44 d2/1f11=0.13 Distance It from image plane to exit pupil: +871.9an
(Seen from the imaging plane, the exit pupil is in the opposite direction from the object.
）絞りは第１面より物体側に１．５ａｅの位置実施例２
ｆ＝］ｏ ２ω＝４８６
１、 １５．６９６
２ ５．２０８
３ ７．６８０
４ −１０，２３６
２４’ Ｆ＝２．８
ｄ ｎ ｖａ
Ｏ，７０１，５１６３３６４，１
２，５０
３，００１，８３４００３７，２
０，５０
５−７，２１６０，７０１，８４６６６２３，８６１０
，００２１，００
７−４６，９６５３，００１，７７２５０４９，６８−
７，１０７０，２０
９５０，４３７２，５０１，，６９６８０５５，５１０
−２４，０４４２，００
１１カバー （−） ４．８４ １．５１６３
３ ６４．１１２ ガラス ω
ｆ１／ｆ２１＝２゜７１ ｄ２／ｌ ｆ１１＝０．
１６結像面から射出瞳までの距ＩＩ ： ＋１８６．６
ｍｍ （結像面から見て、射出瞳は物体と反対の方向に
ある。）絞りは第１面より物体側に１．５ｍｍの位置実
施例３
ｆ＝１０ ２ω＝４５″′
８．６４２
４．４５５
６．６０５
−３５．９５６
〜１２．３３８
１４’ Ｆ＝２．８
ｄ ｎ ヤｄ
Ｏ，５９１，５６８８３５６，３
２，５０
１，６７１，８３４００３７，２
０，５０
０，５９１，８４６６５２３，８
６７，８９２０，７０
７１６６５，５６９２，７６１，７７２５０４’３．６
８ −７．１４９ ０．２０９
−２２６２．７３０ ２．５０ １．５１６
３３ ６４．１１０ −１．２．０５９
２．００１１ カバー ω ４．８４ １
．５１６３３ ６４．１１２ ガラス ψ
ｆ、／ ｆ、Ｉ＝２．５０ ｄ２／Ｉｆ１１＝０．
１５結像面から射出瞳までの距離： −２７０，４ｍｍ
（結像面から見て、射出瞳は物体と同じ方向にある。)The aperture is located 1.5ae closer to the object than the first surface.Example 2 f=]o 2ω=486 1, 15.696 2 5.208 3 7.680 4 -10,236 24' F=2.8 d n va O, 701, 5163364, 1 2, 50 3,001, 8340037, 2 0, 50 5-7, 2160, 701, 8466623, 8610
,0021,00 7-46,9653,001,7725049,68-
7,1070,20 950,4372,501,,6968055,510
-24,0442,00 11 cover (-) 4.84 1.5163
3 64.112 Glass ω f1/f21=2°71 d2/l f11=0.
16 Distance II from imaging plane to exit pupil: +186.6
mm (Viewed from the image plane, the exit pupil is in the opposite direction to the object.) The diaphragm is located 1.5 mm closer to the object than the first surface. Example 3 f=10 2ω=45″' 8.642 4 .455 6.605 -35.956 ~12.338 14' F=2.8 d n Yad O,591,5688356,3 2,50 1,671,8340037,2 0,50 0,591,8466523, 8 67,8920,70 71665,5692,761,772504'3.6
8 -7.149 0.209
-2262.730 2.50 1.516
33 64.110 -1.2.059
2.0011 Cover ω 4.84 1
．． 51633 64.112 Glass ψ f, / f, I=2.50 d2/If11=0.
15 Distance from imaging plane to exit pupil: -270.4mm
(Seen from the imaging plane, the exit pupil is in the same direction as the object.
）絞りは第１面より物体側に１．５ｍの位置（発明の効
果）
この発明の撮影レンズは、レトロフォーカス型で十分な
バックフォーカスを有するだけでなく、テレセントリッ
ク性にも優れ、各実施例の収差図にも見るように、各収
差がバランスよく補正され、しかもコンパクトなレンズ
系を実現し、特にビデオカメラ、スチルビデオカメラ用
として好適である。) The aperture is located 1.5 m closer to the object than the first surface (effects of the invention) The photographic lens of this invention is not only a retrofocus type and has sufficient back focus, but also has excellent telecentricity, and each of the examples As shown in the aberration diagram, each aberration is corrected in a well-balanced manner, and a compact lens system is realized, making it particularly suitable for use in video cameras and still video cameras.
第１図、 第２図、 第３図は、 それぞれこの発明 の撮影レンズの実施例１、 実施例２、 実施例３の レンズ断面図、 第４図、 第５図、 第６図はそれぞ れ、 実施例１、 実施例２、 実施例３の収差図であ る。 Figure 1, Figure 2, Figure 3 shows This invention respectively Example 1 of the photographic lens of Example 2, Example 3 Lens cross section, Figure 4, Figure 5, Figure 6 shows each Re, Example 1, Example 2, This is an aberration diagram of Example 3. Ru.
Claims (1)
メニスカスレンズ、第２レンズは両凸レンズ、第３レン
ズは両凹レンズ、第４レンズは像側に強い凸面を向けた
正レンズ、第５レンズは正レンズの５枚レンズより構成
され、絞りが第１レンズの前方に配置され、次の各条件
を満足することを特徴とするレトロフォーカスタイプの
撮影レンズ ２．２＜｜ｆ＿１／ｆ＿２｜＜３．８ ０．０８＜ｄ＿２／｜ｆ＿１｜＜０．１８ ただし、 ｆ＿１：第１レンズの焦点距離 ｆ＿２：第２レンズの焦点距離 ｄ＿２：第１レンズと第２レンズの間の空気間隔 を示す。[Claims] In order from the object side, the first lens is a negative meniscus lens with a convex surface facing the object side, the second lens is a biconvex lens, the third lens is a biconcave lens, and the fourth lens has a strongly convex surface facing the image side. 2. A retrofocus type photographing lens characterized in that the positive lens and the fifth lens are composed of five positive lenses, the aperture is arranged in front of the first lens, and the following conditions are satisfied. 2<|f_1/f_2|<3.8 0.08<d_2/|f_1|<0.18 However, f_1: Focal length of the first lens f_2: Focal length of the second lens d_2: First lens and second lens Indicates air spacing between lenses.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2141340A JPH0436714A (en) | 1990-06-01 | 1990-06-01 | Retrofocus type photographic lens |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2141340A JPH0436714A (en) | 1990-06-01 | 1990-06-01 | Retrofocus type photographic lens |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0436714A true JPH0436714A (en) | 1992-02-06 |
Family
ID=15289684
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2141340A Pending JPH0436714A (en) | 1990-06-01 | 1990-06-01 | Retrofocus type photographic lens |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0436714A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100463329B1 (en) * | 1997-07-11 | 2005-05-03 | 삼성테크윈 주식회사 | Color Charge Coupled Imaging Optical System |
| CN108802979A (en) * | 2017-08-29 | 2018-11-13 | 成都理想境界科技有限公司 | A kind of short focus projection objective and optical fiber scanning projection device |
| CN111025545A (en) * | 2019-12-23 | 2020-04-17 | 瑞声通讯科技(常州)有限公司 | Image pickup optical lens |
| WO2021127874A1 (en) * | 2019-12-23 | 2021-07-01 | 诚瑞光学(常州)股份有限公司 | Image pickup optical camera |
-
1990
- 1990-06-01 JP JP2141340A patent/JPH0436714A/en active Pending
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100463329B1 (en) * | 1997-07-11 | 2005-05-03 | 삼성테크윈 주식회사 | Color Charge Coupled Imaging Optical System |
| CN108802979A (en) * | 2017-08-29 | 2018-11-13 | 成都理想境界科技有限公司 | A kind of short focus projection objective and optical fiber scanning projection device |
| CN111025545A (en) * | 2019-12-23 | 2020-04-17 | 瑞声通讯科技(常州)有限公司 | Image pickup optical lens |
| WO2021127874A1 (en) * | 2019-12-23 | 2021-07-01 | 诚瑞光学(常州)股份有限公司 | Image pickup optical camera |
| CN111025545B (en) * | 2019-12-23 | 2022-04-15 | 诚瑞光学(常州)股份有限公司 | Image pickup optical lens |
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