JPH11337819A - Photographing optical system of front diaphragm - Google Patents
Photographing optical system of front diaphragmInfo
- Publication number
- JPH11337819A JPH11337819A JP10155430A JP15543098A JPH11337819A JP H11337819 A JPH11337819 A JP H11337819A JP 10155430 A JP10155430 A JP 10155430A JP 15543098 A JP15543098 A JP 15543098A JP H11337819 A JPH11337819 A JP H11337819A
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- Prior art keywords
- optical system
- lens
- photographing optical
- lens group
- positive
- Prior art date
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Abstract
Description
【0001】[0001]
【発明の属する技術分野】本発明は、ビデオカメラや電
子スチルカメラに使用されるレンズ系の前方に絞りを設
けた撮影光学系に関するものである。又本発明は、前記
撮影光学系を備えた撮影装置に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photographic optical system provided with an aperture in front of a lens system used for a video camera or an electronic still camera. The present invention also relates to a photographing device provided with the photographing optical system.
【0002】[0002]
【従来の技術】通常、撮影光学系は、絞りがその内部に
配置されており、入射瞳、射出瞳共に光学系の内部に位
置するように構成されている。しかし、撮影装置によっ
ては、機構上あるいは装置を廉価にするために、絞りや
シャッター等を光学系の前に配置する必要性が生ずる。
特に双眼鏡や、スチルカメラやビデオカメラに備えられ
たファインダーのような観察光学系の接眼部に配置して
撮影を行なう撮影装置の場合、観察光学系の接眼レンズ
の射出瞳が絞り位置になるため、撮影装置に用いられる
撮影光学系は、例えば特開昭49−53423号公報に
記載されているような前置絞りの光学系が一般的であ
る。2. Description of the Related Art Usually, a photographing optical system has a stop disposed therein, and both an entrance pupil and an exit pupil are located inside the optical system. However, depending on the photographing apparatus, it may be necessary to arrange an aperture, a shutter, and the like in front of the optical system in order to reduce the cost of the mechanism or the apparatus.
In particular, in the case of a photographing apparatus that arranges in an eyepiece part of an observation optical system such as a binocular or a viewfinder provided in a still camera or a video camera and performs photographing, the exit pupil of the eyepiece of the observation optical system is at the aperture position. For this reason, as a photographing optical system used in a photographing apparatus, for example, an optical system of a front stop as described in Japanese Patent Application Laid-Open No. 49-53423 is generally used.
【0003】また、ビデオカメラや電子スチルカメラ
は、撮影光学系により結像された被写体像を固体撮像素
子を用いて撮像するように構成されている。この固体撮
像素子は、その撮像面上に微小レンズを形成し、それに
より受光量を増大させるようにしている。そのため、固
体撮像素子の撮像面に入射する光束は、その入射角が小
になるようにすることが好ましく、言い換えれば、撮影
光学系の射出瞳が撮像面から十分遠くに位置するように
することが望ましい。[0005] Video cameras and electronic still cameras are configured to capture a subject image formed by a photographic optical system using a solid-state image sensor. In this solid-state imaging device, a micro lens is formed on the imaging surface, thereby increasing the amount of received light. Therefore, it is preferable that the light beam incident on the imaging surface of the solid-state imaging device has a small incident angle. In other words, the exit pupil of the imaging optical system is located sufficiently far from the imaging surface. Is desirable.
【0004】また撮影光学系と固体撮像素子との間に
は、モアレを防ぐためのローパスフィルターや赤外光を
カットするための赤外カットフィルター等を配置する必
要があり、撮影光学系のバックフォーカスを十分長くす
る必要がある。Further, it is necessary to dispose a low-pass filter for preventing moire, an infrared cut filter for cutting infrared light, and the like between the photographing optical system and the solid-state image pickup device. The focus needs to be long enough.
【0005】[0005]
【発明が解決しようとする課題】絞りを光学系の前に配
置すると、光学系が絞りに対して対称性の悪い構成にな
り、歪曲収差が発生し、また軸上収差と軸外収差のバラ
ンスがとりにくく、周辺におけるコマ収差の発生が大に
なり結像性能が劣化する。When the stop is arranged in front of the optical system, the optical system has a structure with poor symmetry with respect to the stop, distortion occurs, and a balance between on-axis aberration and off-axis aberration is obtained. And the occurrence of coma in the periphery becomes large, and the imaging performance deteriorates.
【0006】又、双眼鏡や、カメラ等に備えられたファ
インダーのような観察光学系の接眼部に撮影光学系を取
り付けて撮影を行なう場合、観察光学系の射出瞳径と撮
影光学系の入射瞳径とを等しくするか、またはそれより
大きくすることが望まれる。この場合、周知のようにフ
ロント絞りタイプの光学系は、入射瞳径が絞り径に相当
する。また観察光学系は、射出瞳径が人間が観察するこ
とを考慮して設計されている。そのために、撮影装置に
用いられる撮影光学系の入射瞳径は、撮影光学系の光学
的仕様にかかわらず、人間の眼の瞳径に相当する3mm
〜8mm程度が望まれる。When photographing is performed by attaching a photographing optical system to an eyepiece of an observation optical system such as a binocular or a viewfinder provided in a camera or the like, the exit pupil diameter of the observation optical system and the incident light of the photographing optical system. It is desired to make the pupil diameter equal or larger. In this case, as is well known, in the front stop type optical system, the entrance pupil diameter corresponds to the stop diameter. The observation optical system is designed in consideration of the fact that the exit pupil diameter is observed by a human. Therefore, the entrance pupil diameter of the photographing optical system used in the photographing apparatus is 3 mm corresponding to the pupil diameter of the human eye regardless of the optical specifications of the photographing optical system.
About 8 mm is desired.
【0007】このような要求に対して、3枚構成のトリ
プレットタイプや4枚構成のテッサータイプ等の少ない
枚数のレンズにて構成された低コストのフロント絞り光
学系が提案されている。しかし、近年、ビデオカメラや
電子スチルカメラの小型化や高画質化への要求により、
固体撮像素子も小型化、高画質化が図られている。それ
に伴って、撮影光学系は、第1に固体撮像素子の高画素
化による高周波性能の向上、第2に固体撮像素子の小型
化による短焦点距離化が求められ、又入射瞳を人間の瞳
の瞳径に対応させるために縮小し得ないことから、大口
径比が求められ、そのために、前記タイプの光学系では
前述の要求を満たすことは困難である。[0007] In response to such a demand, a low-cost front stop optical system composed of a small number of lenses, such as a triplet-type triplet type and a four-element Tessar type, has been proposed. However, in recent years, due to the demand for miniaturization and high image quality of video cameras and electronic still cameras,
Solid-state imaging devices have also been reduced in size and improved in image quality. Accordingly, the photographing optical system is required to firstly improve the high frequency performance by increasing the number of pixels of the solid-state imaging device, and secondly to shorten the focal length by reducing the size of the solid-state imaging device. Since the size cannot be reduced in order to correspond to the pupil diameter, a large aperture ratio is required. Therefore, it is difficult for the above-mentioned type of optical system to satisfy the above requirements.
【0008】そのため、撮影光学系のレンズ枚数を増や
すことにより、前述の要求を満足するようにした光学系
として、特開昭52−32323号公報や特開平8−2
78443号公報等に記載された光学系が知られてい
る。For this reason, an optical system which satisfies the above-mentioned requirements by increasing the number of lenses of the photographing optical system is disclosed in Japanese Patent Laid-Open Publication No.
An optical system described in, for example, Japanese Patent No. 78443 is known.
【0009】これら従来例のうち、特開昭52−323
23号公報に記載された光学系は、5群7枚構成のフロ
ント絞りで、入射瞳径が7mm程度、Fナンバーが約
1.2の明るい撮影光学系である。しかし、バックフォ
ーカスが短く、ローパスフィルターや赤外カットフィル
ター等の光学フィルターを配置するスペースがなくこれ
らフィルターを配置できないためにモアレが発生した
り、赤外光によるフレアーによりコントラストが低下す
る欠点がある。Among these conventional examples, Japanese Patent Application Laid-Open No. 52-323
The optical system described in Japanese Patent Publication No. 23 is a bright photographing optical system having a front stop having five elements in seven groups, an entrance pupil diameter of about 7 mm, and an F-number of about 1.2. However, the back focus is short, and there is no space for disposing an optical filter such as a low-pass filter or an infrared cut filter. These filters cannot be disposed, so that moire occurs or the contrast is reduced due to flare by infrared light. .
【0010】又、特開平8−278443号公報に記載
された光学系は、4群5枚構成のフロント絞りの小型な
撮影光学系であるが、Fナンバーが3.4程度で暗く、
絞り径が2.2mm程度であって小さい。そのために、
この光学系を観察光学系の接眼部に配置して使用する場
合、観察光学系の射出瞳径を撮影光学系の絞りによって
人間の眼の瞳径よりも小さく絞ることになり、撮影光学
系により形成される像は、人間が観察する状態に対し暗
くなり、又観察視野がけられやすく、被写界深度が深く
なる等の相違が生じ、用途として好ましくない。The optical system described in Japanese Patent Application Laid-Open No. 8-278443 is a small photographing optical system having a four-group, five-panel front aperture, but has an F number of about 3.4 and is dark.
The aperture diameter is as small as about 2.2 mm. for that reason,
When this optical system is used by placing it on the eyepiece of the observation optical system, the exit pupil diameter of the observation optical system is reduced to be smaller than the pupil diameter of the human eye by the aperture of the imaging optical system. The image formed by the method is darker than the state observed by a human, and the observation field of view tends to be blurred, and the depth of field becomes deep.
【0011】本発明は、ビデオカメラや電子スチルカメ
ラの使用に適した、バックフォーカスが十分に確保され
たフロント絞りの光学系で、観察光学系の接眼部に配置
して観察光学系の視野を観察記録するために好適なをフ
ロント絞りの撮影光学系を提供するものである。The present invention is directed to an optical system of a front diaphragm, which is suitable for use in a video camera or an electronic still camera and has a sufficient back focus, and which is disposed at an eyepiece of the observation optical system to provide a visual field of the observation optical system. The present invention is to provide a photographing optical system having a front aperture suitable for observing and recording the image.
【0012】[0012]
【課題を解決するための手段】本発明のフロント絞りの
撮影光学系は、物体側から順に、正レンズよりなる第1
レンズ群と物体側に強い凹面を向けた負レンズよりなる
第2レンズ群と物体側に強い凹面を向けたメニスカスレ
ンズの第3レンズ群と像側に強い凸面を向けた正レンズ
の第4レンズ群と正の屈折力の接合レンズよりなる第5
レンズ群よりなり、下記条件(1)を満足することを特
徴とする。 (1) 0.7f<fB<1.1f ただしfは撮影光学系全系の焦点距離、fBは撮影光学
系のバックフォーカスである。The photographing optical system of the front diaphragm according to the present invention comprises, in order from the object side, a first lens comprising a positive lens.
A second lens group consisting of a lens group and a negative lens having a strong concave surface facing the object side, a third lens group of a meniscus lens having a strong concave surface facing the object side, and a fourth lens being a positive lens having a strong convex surface facing the image side Fifth lens consisting of a group and a cemented lens having a positive refractive power
The zoom lens is composed of a lens group and satisfies the following condition (1). (1) 0.7f <f B <1.1f where f is the focal length of the entire photographing optical system, and f B is the back focus of the photographing optical system.
【0013】本発明の撮影光学系は、5群6枚構成で、
第1レンズ群から第4レンズ群まででほぼレトロフォー
カスタイプのレンズ構成にして光学系のバックフォーカ
スを確保するようにしてある。又第5レンズ群を接合レ
ンズにして色収差特に倍率の色収差を補正するようにし
ている。The photographing optical system according to the present invention comprises six elements in five groups.
The first lens group to the fourth lens group have a substantially retrofocus type lens configuration to ensure the back focus of the optical system. The fifth lens group is a cemented lens to correct chromatic aberration, particularly chromatic aberration of magnification.
【0014】周知のようにレトロフォーカスタイプの光
学系は、物体側に負の屈折力を有する光学要素と、像側
に正の屈折力を有する光学要素とを配置した構成であ
る。As is well known, a retrofocus type optical system has a configuration in which an optical element having a negative refractive power is arranged on the object side and an optical element having a positive refractive power is arranged on the image side.
【0015】本発明の光学系の第1レンズ群から第4レ
ンズ群においてこのような構成にするために、第2レン
ズ群を物体側に強い負のパワーを有する負レンズに又第
3レンズ群を物体側に強い負のパワーを有するメニスカ
スレンズにし、又第4レンズ群を像側に強い正のパワー
を有する正レンズにした。このようにして第3レンズ群
の物体側の面までを負の屈折力を有する光学要素とし又
第3レンズ群の像側の面以降を正の屈折力を有する光学
要素としてほぼレトロフィーカスタイプに構成した。ま
た、第1レンズ群に正レンズを配置して光学系の球面収
差とコマ収差を補正するようにしている。第3レンズ群
をメニスカスレンズにして第3レンズ群の物体側の面と
像側の面で互いにペッツバール和を打ち消すようにし、
これにより、各レンズ面のパワーが比較的強いにも拘ら
ず第3レンズ群の偏芯による性能の変化を少なくでき
る。In order to make such a configuration in the first to fourth lens units of the optical system according to the present invention, the second lens unit is replaced by a negative lens having strong negative power on the object side and the third lens unit. Is a meniscus lens having strong negative power on the object side, and the fourth lens group is a positive lens having strong positive power on the image side. In this manner, the third lens group is substantially an optical element having a negative refractive power up to the object-side surface and the optical element having a positive refractive power after the image-side surface of the third lens group. Configured. Further, a positive lens is arranged in the first lens group to correct spherical aberration and coma of the optical system. Making the third lens group a meniscus lens so that the object side surface and the image side surface of the third lens group cancel out Petzval sum each other;
Thus, the change in performance due to the eccentricity of the third lens group can be reduced despite the relatively strong power of each lens surface.
【0016】また、第5レンズ群を正のパワーにするこ
とにより、撮影光学系の射出瞳位置が像面から遠くなる
ようにし、光学系をテレセントリックに近い状態にして
フォーカシングによる像の大きさが変化しないか変化が
少ない光学系にしている。これにより、観察光学系の接
眼部に配置して撮影を行なう撮影装置の光学系として使
用するのに有効である。Further, by setting the fifth lens group to have a positive power, the exit pupil position of the photographing optical system is made far from the image plane, and the optical system is made close to telecentric so that the size of the image by focusing is reduced. The optical system does not change or changes little. This is effective for use as an optical system of a photographing apparatus that performs photographing by arranging it on the eyepiece of the observation optical system.
【0017】又、本発明の撮影光学系は、前記条件
(1)を満足するようにしている。この条件(1)にお
いて、下限の0.7fを下回るとローパスフィルターや
赤外カットフィルター等の光学フィルターを撮影光学系
と撮像面との間に配置することができなくなり、用途が
限定されるため好ましくない。また条件(1)において
上限の1.1fを超えると後群(像側のレンズ群)の径
が大になるとともに軸外収差の発生が著しくなる。また
光学系の全長を短くしようとすると第2レンズ群のパワ
ーが強くなりそれに伴い収差の発生量が大になり特に球
面収差とペッツバール和の補正が困難になる。The photographing optical system according to the present invention satisfies the above condition (1). In the condition (1), if the lower limit of 0.7f is not reached, an optical filter such as a low-pass filter or an infrared cut filter cannot be disposed between the photographing optical system and the imaging surface, and the use is limited. Not preferred. When the value exceeds the upper limit of 1.1f in the condition (1), the diameter of the rear unit (the lens unit on the image side) becomes large, and off-axis aberrations are remarkably generated. If the total length of the optical system is to be shortened, the power of the second lens group is increased, and accordingly, the amount of generated aberration is increased, and it is particularly difficult to correct spherical aberration and Petzval sum.
【0018】本発明の撮影光学系において、下記条件
(2)を満足すれば望ましい。 (2) −0.3<R2F/R2R<0.3 ただし、R2F、R2Rは夫々第2レンズ群の物体側の面お
よび像側の面の曲率半径である。In the photographing optical system of the present invention, it is desirable that the following condition (2) is satisfied. (2) −0.3 <R 2F / R 2R <0.3 where R 2F and R 2R are the radii of curvature of the object-side surface and the image-side surface of the second lens unit, respectively.
【0019】条件(2)は、第2レンズ群のベンディン
グに関する条件である。物体側に強い凹面を向けた負レ
ンズである第2レンズ群が、上記条件(2)において上
限の0.3を上回るとこのレンズ群の屈折力が弱くなり
光学系をレトロフィーカスタイプの構成になし得なくな
りバックフォーカスを確保できなくなるか夫々の面の屈
折力が極端に強くなり収差の発生量が大になり補正が困
難になる。又下限の−0.3を下回ると第2レンズ群の
夫々の面でコマ収差が発生し、偏芯した時の周辺性能の
劣化が大になる。Condition (2) is a condition relating to bending of the second lens group. When the second lens group, which is a negative lens having a strong concave surface facing the object side, exceeds the upper limit of 0.3 in the above condition (2), the refractive power of this lens group becomes weak, and the optical system is configured as a retrophy-type. Or the back focus cannot be secured, or the refractive power of each surface becomes extremely strong, and the amount of aberrations increases, making correction difficult. If the lower limit of -0.3 is not reached, coma is generated on each surface of the second lens unit, and the peripheral performance is greatly deteriorated when decentered.
【0020】又、本発明の撮影光学系において、下記条
件(3)を満足することができる。 (3) 10<ν1−ν2<25 ただし、ν1,ν2は夫々第1レンズ群および第2レンズ
群のアッベ数である。In the photographing optical system according to the present invention, the following condition (3) can be satisfied. (3) 10 <ν 1 −ν 2 <25 where, ν 1 and ν 2 are Abbe numbers of the first lens unit and the second lens unit, respectively.
【0021】この条件(3)は、第1レンズ群と第2レ
ンズ群とのアッベ数を規定するもので、これによって光
学系の軸上色収差を良好に補正し得る。The condition (3) defines the Abbe number of the first lens unit and the second lens unit, whereby the axial chromatic aberration of the optical system can be corrected well.
【0022】この条件(3)において、下限の10を下
回ると軸上色収差が補正不足になり、上限の25を上回
ると軸上色収差が補正過剰に成る。In condition (3), if the value is below the lower limit of 10, axial chromatic aberration will be undercorrected, and if the value exceeds the upper limit of 25, axial chromatic aberration will be overcorrected.
【0023】本発明の撮影光学系において、下記条件
(4)を満足すれば望ましい。 (4) 1.57<nd2<1.75 ただし、nd2は第2レンズ群の屈折力である。In the photographing optical system of the present invention, it is desirable that the following condition (4) is satisfied. (4) 1.57 < nd2 <1.75 where nd2 is the refractive power of the second lens group.
【0024】条件(4)は、第2レンズ群の屈折力を規
定するもので、この条件(4)において上限の1.75
を上回るとベッツバール和が補正不足に成り、下限の
1.57を下回ると第2レンズ群の面の曲率半径を小さ
くせざるを得なくなり、球面収差が発生し収差補正が困
難になる。The condition (4) defines the refractive power of the second lens unit, and the upper limit of the condition (4) is 1.75.
Exceeds the lower limit of 1.57, the radius of curvature of the surface of the second lens unit must be reduced, and spherical aberration occurs, making it difficult to correct the aberration.
【0025】前記の条件(2)乃至条件(4)はいずれ
か一つを満足すればよいが、そのすべてを満足すれば特
に好ましい。又、条件(2)乃至条件(4)のうちのい
ずれか二つの条件を満足するようにしてもよい。Any one of the above conditions (2) to (4) may be satisfied, but it is particularly preferable that all of them are satisfied. Further, any two of the conditions (2) to (4) may be satisfied.
【0026】又、本発明の撮影光学系は、前記条件
(1)乃至条件(4)の代りに下記条件(1−1)、
(2−1)、(3−1)、(4−1)を満足すればより
望ましい。 (1−1) 0.8f<fB<1.0f (2−1) −0.3<R2F/R2R<−0.1 (3−1) 15<ν1−ν2<25 (4−1) 1.60<nd2<1.70The photographing optical system according to the present invention has the following conditions (1-1) instead of conditions (1) to (4).
It is more desirable to satisfy (2-1), (3-1), and (4-1). (1-1) 0.8f <f B < 1.0f (2-1) -0.3 <R 2F / R 2R <-0.1 (3-1) 15 <ν 1 -ν 2 <25 ( 4-1) 1.60 < nd2 <1.70
【0027】これら条件は、その一つ又は一部を満足す
るようにしてもよい。These conditions may satisfy one or a part of them.
【0028】又、条件(3)又は条件(3−1)の代わ
りに下記条件(3−2)を満足すればより望ましい。 (3−2) 18<ν1−ν2<23It is more preferable that the following condition (3-2) is satisfied instead of the condition (3) or the condition (3-1). (3-2) 18 <ν 1 −ν 2 <23
【0029】[0029]
【発明の実施の形態】次に本発明の撮影光学系の実施の
形態を下記実施例をもとに述べる。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the photographing optical system of the present invention will be described based on the following examples.
【0030】 実施例1 f=11.588,F/2.318 r1=∞(絞り) d1=1.000 r2=-18.987 d2=1.616 n1=1.640 ν1=60.07 r3= -8.320 d3=2.643 r4= -4.312 d4=0.936 n2=1.581 ν2=40.75 r5=-15.234 d5=1.419 r6= -7.241 d6=3.945 n3=1.816 ν3=46.62 r7= -7.171 d7=0.200 r8=-97.887 d8=2.154 n4=1.816 ν4=46.62 r9=-18.640 d9=0.200 r10= 24.836 d10=4.641 n5=1.741 ν5=52.64 r11= -9.897 d11=0.988 n6=1.847 ν6=23.78 r12=-88.212 d12=7.210 r13=∞ d13=4.500 n7=1.516 ν7=64.14 r14=∞ d14=2.375 fB/f=1.083,r2F/r2R=0.283,ν1−ν2=19.32 nd2=1.581Example 1 f = 11.588, F / 2.318 r 1 = ∞ (aperture) d 1 = 1.000 r 2 = -18.987 d 2 = 1.616 n 1 = 1.640 ν 1 = 60.07 r 3 = -8.320 d 3 = 2.643 r 4 = -4.312 d 4 = 0.936 n 2 = 1.581 ν 2 = 40.75 r 5 = -15.234 d 5 = 1.419 r 6 = -7.241 d 6 = 3.945 n 3 = 1.816 ν 3 = 46.62 r 7 = -7.171 d 7 = 0.200 r 8 = -97.887 d 8 = 2.154 n 4 = 1.816 ν 4 = 46.62 r 9 = -18.640 d 9 = 0.200 r 10 = 24.836 d 10 = 4.641 n 5 = 1.741 ν 5 = 52.64 r 11 = -9.897 d 11 = 0.988 n 6 = 1.847 ν 6 = 23.78 r 12 = -88.212 d 12 = 7.210 r 13 = ∞ d 13 = 4.500 n 7 = 1.516 ν 7 = 64.14 r 14 = ∞ d 14 = 2.375 f B /f=1.083 , r 2F / r 2R = 0.283 , ν 1 -ν 2 = 19.32 n d2 = 1.581
【0031】 実施例2 f=11.596,F/1.611 r1=∞(絞り) d1=1.000 r2= 23.067 d2=2.319 n1=1.755 ν1=52.32 r3=-15.169 d3=1.882 r4= -6.600 d4=0.842 n2=1.689 ν2=31.07 r5= 22.490 d5=2.156 r6= -6.380 d6=3.443 n3=1.834 ν3=37.16 r7= -7.551 d7=0.200 r8= 45.820 d8=3.511 n4=1.816 ν4=46.62 r9=-14.726 d9=0.200 r10=13.804 d10=4.736 n5=1.603 ν5=65.44 r11=-12.411 d11=0.986 n6=1.847 ν6=23.78 r12=44.835 d12=3.060 r13=∞ d13=4.500 n7=1.516 ν7=64.14 r14=∞ d14=2.375 fB/f=0.725,r2F/r2R=−0.293,ν1−ν2=21.25 nd2=1.689Example 2 f = 11.596, F / 1.611 r 1 = ∞ (aperture) d 1 = 1.000 r 2 = 23.067 d 2 = 2.319 n 1 = 1.755 ν 1 = 52.32 r 3 = -15.169 d 3 = 1.882 r 4 = -6.600 d 4 = 0.842 n 2 = 1.689 ν 2 = 31.07 r 5 = 22.490 d 5 = 2.156 r 6 = -6.380 d 6 = 3.443 n 3 = 1.834 ν 3 = 37.16 r 7 = -7.551 d 7 = 0.200 r 8 = 45.820 d 8 = 3.511 n 4 = 1.816 ν 4 = 46.62 r 9 = -14.726 d 9 = 0.200 r 10 = 13.804 d 10 = 4.736 n 5 = 1.603 ν 5 = 65.44 r 11 = -12.411 d 11 = 0.986 n 6 = 1.847 ν 6 = 23.78 r 12 = 44.835 d 12 = 3.060 r 13 = ∞ d 13 = 4.500 n 7 = 1.516 ν 7 = 64.14 r 14 = ∞ d 14 = 2.375 f B /f=0.725,r 2F / r 2R = -0.293, ν 1 -ν 2 = 21.25 n d2 = 1.689
【0032】 実施例3 f=11.593,F/2.321 r1=∞(絞り) d1=1.000 r2=105.876 d2=2.200 n1=1.757 ν1=47.82 r3= -9.777 d3=1.500 r4= -5.005 d4=1.000 n2=1.620 ν2=36.26 r5= 47.216 d5=1.700 r6= -6.680 d6=3.067 n3=1.834 ν3=37.16 r7= -7.270 d7=0.200 r8=-412.744 d8=3.021 n4=1.772 ν4=49.60 r9=-11.261 d9=0.200 r10=16.022 d10=3.879 n5=1.603 ν5=65.44 r11=-12.229 d11=1.000 n6=1.847 ν6=23.78 r12=103.295 d12=4.980 r13=∞ d13=4.500 n7=1.516 ν7=64.14 r14=∞ d14=2.375 fB/f=0.890,r2F/r2R=−0.106,ν1−ν2=11.56 nd2=1.620 ただし、r1,r2,・・・は各レンズ面の曲率半径、d
1,d2,・・・は各レンズの肉厚および空気間隔、
n1,n2,・・・は各レンズのd線に対する屈折率、ν
1,ν2,・・・は各レンズのアッベ数である。[0032] Example 3 f = 11.593, F / 2.321 r 1 = ∞ ( stop) d 1 = 1.000 r 2 = 105.876 d 2 = 2.200 n 1 = 1.757 ν 1 = 47.82 r 3 = -9.777 d 3 = 1.500 r 4 = -5.005 d 4 = 1.000 n 2 = 1.620 ν 2 = 36.26 r 5 = 47.216 d 5 = 1.700 r 6 = -6.680 d 6 = 3.067 n 3 = 1.834 ν 3 = 37.16 r 7 = -7.270 d 7 = 0.200 r 8 = -412.744 d 8 = 3.021 n 4 = 1.772 ν 4 = 49.60 r 9 = -11.261 d 9 = 0.200 r 10 = 16.022 d 10 = 3.879 n 5 = 1.603 ν 5 = 65.44 r 11 = -12.229 d 11 = 1.000 n 6 = 1.847 ν 6 = 23.78 r 12 = 103.295 d 12 = 4.980 r 13 = ∞ d 13 = 4.500 n 7 = 1.516 ν 7 = 64.14 r 14 = ∞ d 14 = 2.375 f B /f=0.890,r 2F / r 2R = -0.106, ν 1 -ν 2 = 11.56 n d2 = 1.620 However, r 1, r 2, ··· is the radius of curvature of each lens surface, d
1 , d 2 ,... Are the thickness of each lens and the air gap,
, n 1 , n 2 ,.
1 , ν 2 ,... Are Abbe numbers of the respective lenses.
【0033】実施例1は、図1に示す通りの構成で、物
体側より順に、絞りSと、正のメニスカスレンズの第1
レンズ群L1と、物体側に強い凹面を向けた負のメニス
カスレンズの第2レンズ群L2と、物体側に強い凹面を
向けた正のメニスカスレンズの第3レンズ群L3と、像
側に強い凸面を向けた正のメニスカスレンズの第4レン
ズ群L4と、両凸レンズと負のメニスカスレンズとを接
合した正の屈折力の接合レンズの第5レンズ群L5より
なり、その像側にローパスフィルター又は赤外カットフ
ィルターの光学素子L6を配置している。In the first embodiment, the stop S and the first meniscus lens of the positive meniscus lens are arranged in order from the object side with the configuration shown in FIG.
A lens unit L1, a second lens unit L2 of a negative meniscus lens having a strong concave surface facing the object side, a third lens unit L3 of a positive meniscus lens having a strong concave surface facing the object side, and a strong convex surface facing the image side And a fifth lens unit L5 of a cemented lens having a positive refractive power in which a biconvex lens and a negative meniscus lens are cemented. A low-pass filter or red The optical element L6 of the outer cut filter is arranged.
【0034】実施例2は、図2に示す構成の光学系で、
物体側より順に、絞りSと、両凸レンズの第1レンズ群
L1と、物体側に強い凹面を向けた両凹レンズの第2レ
ンズ群L2と、物体側に強い凹面を向けた正のメニスカ
スレンズの第3レンズ群L3と、像側に強い凸面を向け
た両凸レンズの第4レンズ群L4と、両凸レンズと両凹
レンズとを接合した正の屈折力の接合レンズの第5レン
ズ群L5よりなり、第5レンズ群L5と像面との間に光
学素子L6を配置している。Embodiment 2 is an optical system having the structure shown in FIG.
In order from the object side, a stop S, a first lens unit L1 of a biconvex lens, a second lens unit L2 of a biconcave lens with a strong concave surface facing the object side, and a positive meniscus lens with a strong concave surface facing the object side A third lens unit L3, a fourth lens unit L4 of a biconvex lens having a strong convex surface facing the image side, and a fifth lens unit L5 of a cemented lens having a positive refractive power in which the biconvex lens and the biconcave lens are joined. An optical element L6 is arranged between the fifth lens unit L5 and the image plane.
【0035】実施例3は、図3の通りの構成で、絞りS
と、両凸レンズの第1レンズ群L1と、物体側に強い凹
面を向けた両凹レンズの第2レンズ群L2と、物体側に
強い凹面を向けた正のメニスカスレンズの第3レンズ群
L3と、像側に強い凸面を向けた正のメニスカスレンズ
の第4レンズ群L4と、両凸レンズと両凹レンズとを接
合した正の屈折力を有する接合レンズの第5レンズ群L
5よりなり、第5レンズ群L5と像面との間に光学素子
L6を配置した構成である。The third embodiment has a configuration as shown in FIG.
A first lens unit L1 of a biconvex lens, a second lens unit L2 of a biconcave lens having a strong concave surface facing the object side, and a third lens unit L3 of a positive meniscus lens having a strong concave surface facing the object side. A fourth lens unit L4 of a positive meniscus lens having a strong convex surface facing the image side, and a fifth lens unit L of a cemented lens having a positive refracting power obtained by cementing a biconvex lens and a biconcave lens
5, and an optical element L6 is arranged between the fifth lens unit L5 and the image plane.
【0036】実施例1,2,3の収差状況は、夫々図
4,5,6に示す通りで、図中IHは像高である。The aberrations in the first, second, and third embodiments are as shown in FIGS. 4, 5, and 6, respectively, where IH is the image height.
【0037】以上述べた撮影光学系において、特許請求
の範囲に記載する光学系のほかに次の各項に記載する構
成の光学系も本発明の目的を達成し得るものである。In the photographing optical system described above, an optical system having the configuration described in each of the following items in addition to the optical system described in the claims can also achieve the object of the present invention.
【0038】(1) 特許請求の範囲の請求項1、2又
は3に記載する光学系で、下記条件(4)を満足するこ
とを特徴とする撮影光学系。 (4) 1.57<nd2<1.75(1) An optical system according to claim 1, 2 or 3, which satisfies the following condition (4): (4) 1.57 < nd2 <1.75
【0039】(2) 特許請求の範囲の請求項1、2又
は3あるいは前記の(1)の項に記載する光学系で、条
件(1)の代りに下記条件(1−1)を満足することを
特徴とする撮影光学系。 (1−1) 0.8f<fB<1.0f(2) The optical system according to claim 1, 2, or 3, or the above item (1), wherein the following condition (1-1) is satisfied instead of the condition (1). An imaging optical system characterized in that: (1-1) 0.8f <f B < 1.0f
【0040】(3) 特許請求の範囲の請求項2又は3
あるいは前記の(1)又は(2)の項に記載する光学系
で、条件(2)の代りに下記条件(2−1)を満足する
ことを特徴とする撮影光学系。 (2−1) −0.3<R2F/R2R<−0.1(3) Claim 2 or 3 of the claims
Alternatively, the optical system described in the above item (1) or (2), wherein the following condition (2-1) is satisfied instead of the condition (2). (2-1) −0.3 <R 2F / R 2R <−0.1
【0041】(4) 特許請求の範囲の請求項3あるい
は前記の(1)、(2)又は(3)の項に記載する光学
系で、条件(3)の代りに下記条件(3−1)を満足す
ることを特徴とする撮影光学系。 (3−1) 15<ν1−ν2<25(4) In the optical system described in claim 3 or (1), (2) or (3), the following condition (3-1) is used instead of condition (3). An imaging optical system characterized by satisfying (1). (3-1) 15 <ν 1 −ν 2 <25
【0042】(5) 前記の(4)の項に記載する光学
系で、条件(3−1)の代りに下記条件(3−2)を満
足することを特徴とする撮影光学系。 (3−2) 18<ν1−ν2<23(5) The optical system described in the above item (4), wherein the following condition (3-2) is satisfied instead of the condition (3-1). (3-2) 18 <ν 1 −ν 2 <23
【0043】(6) 前記の(1)、(2)、(3)、
(4)又は(5)の項に記載する光学系で、条件(4)
の代りに下記条件(4−1)を満足することを特徴とす
る撮影光学系。 (4) 1.60<nd2<1.70(6) The above (1), (2), (3),
In the optical system described in the item (4) or (5), the condition (4) is satisfied.
A photographing optical system satisfying the following condition (4-1) instead of (4) 1.60 < nd2 <1.70
【0044】(7) 特許請求の範囲の請求項1、2又
は3あるいは前記の(1)、(2)、(3)、(4)、
(5)又は(6)の項に記載する光学系を備えた撮影装
置で、前記光学系を他の光学系である射出瞳が最終レン
ズ面よりも後方にあるアフォーカル光学系に装着して観
察又は撮影するようにしたことを特徴とする撮影装置。(7) Claims 1, 2 or 3 of the claims or the above (1), (2), (3), (4),
(5) or a photographing apparatus provided with the optical system described in (6), wherein the optical system is mounted on an afocal optical system in which an exit pupil, which is another optical system, is located behind the final lens surface. An imaging device characterized in that observation or imaging is performed.
【0045】[0045]
【発明の効果】本発明のフロント絞り撮影光学系は、バ
ックフォーカスが長くビデオカメラや電子スチルカメラ
に適しており又観察光学装置の接眼部に取り付けての観
察や撮影に適している。The front aperture photographing optical system of the present invention has a long back focus and is suitable for a video camera or an electronic still camera, and is also suitable for observation and photographing by being attached to an eyepiece of an observation optical device.
【図1】 本発明の実施例1の断面図FIG. 1 is a sectional view of a first embodiment of the present invention.
【図2】 本発明の実施例2の断面図FIG. 2 is a sectional view of a second embodiment of the present invention.
【図3】 本発明の実施例3の断面図FIG. 3 is a sectional view of a third embodiment of the present invention.
【図4】 本発明の実施例1の収差曲線図FIG. 4 is an aberration curve diagram according to the first embodiment of the present invention.
【図5】 本発明の実施例2の収差曲線図FIG. 5 is an aberration curve diagram according to the second embodiment of the present invention.
【図6】 本発明の実施例3の収差曲線図FIG. 6 is an aberration curve diagram according to a third embodiment of the present invention.
Claims (3)
1レンズ群と物体側に強い凹面を向けた負レンズよりな
る第2レンズ群と物体側に強い凹面を向けたメニスカス
レンズの第3レンズ群と像側に強い凸面を向けた正レン
ズの第4レンズ群と正の屈折力の接合レンズよりなる第
5レンズ群よりなり、下記条件(1)を満足するフロン
ト絞りの撮影光学系。 (1) 0.7f<fB<1.1f ただしfは撮影光学系全系の焦点距離、fBは撮影光学
系のバックフォーカスである。1. A first lens group consisting of a positive lens, a second lens group consisting of a negative lens having a strong concave surface facing the object side, and a third lens of a meniscus lens having a strong concave surface facing the object side in order from the object side. A photographing optical system of a front stop, which includes a fourth lens unit of a positive lens having a strong convex surface facing the group and the image side and a fifth lens unit of a cemented lens having a positive refractive power, and satisfies the following condition (1). (1) 0.7f <f B <1.1f where f is the focal length of the entire photographing optical system, and f B is the back focus of the photographing optical system.
撮影光学系。 (2) −0.3<R2F/R2R<0.3 ただし、R2F、R2Rは夫々第2レンズ群の物体側および
像側の面の曲率半径である。2. The photographing optical system according to claim 1, wherein the following condition (2) is satisfied. (2) -0.3 < R2F / R2R <0.3 where R2F and R2R are the radii of curvature of the object-side and image-side surfaces of the second lens unit, respectively.
は請求項2の撮影光学系。 (3) 10<ν1−ν2<25 ただし、ν1,ν2は夫々第1レンズ群および第2レンズ
群のアッベ数である。3. The photographing optical system according to claim 1, wherein the following condition (3) is satisfied. (3) 10 <ν 1 −ν 2 <25 where, ν 1 and ν 2 are Abbe numbers of the first lens unit and the second lens unit, respectively.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP10155430A JPH11337819A (en) | 1998-05-21 | 1998-05-21 | Photographing optical system of front diaphragm |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP10155430A JPH11337819A (en) | 1998-05-21 | 1998-05-21 | Photographing optical system of front diaphragm |
Publications (1)
Publication Number | Publication Date |
---|---|
JPH11337819A true JPH11337819A (en) | 1999-12-10 |
Family
ID=15605856
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP10155430A Withdrawn JPH11337819A (en) | 1998-05-21 | 1998-05-21 | Photographing optical system of front diaphragm |
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JP (1) | JPH11337819A (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2002131631A (en) * | 2000-10-23 | 2002-05-09 | Fuji Photo Optical Co Ltd | Single focus lens |
WO2019187874A1 (en) * | 2018-03-28 | 2019-10-03 | ソニー株式会社 | Optical system for rigid scope, imaging device, and endoscopic system |
US10520704B2 (en) | 2017-01-19 | 2019-12-31 | Largan Precision Co., Ltd. | Optical image assembly, image capturing apparatus and electronic device |
-
1998
- 1998-05-21 JP JP10155430A patent/JPH11337819A/en not_active Withdrawn
Cited By (10)
Publication number | Priority date | Publication date | Assignee | Title |
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JP2002131631A (en) * | 2000-10-23 | 2002-05-09 | Fuji Photo Optical Co Ltd | Single focus lens |
JP4628537B2 (en) * | 2000-10-23 | 2011-02-09 | 富士フイルム株式会社 | Single focus lens |
US10520704B2 (en) | 2017-01-19 | 2019-12-31 | Largan Precision Co., Ltd. | Optical image assembly, image capturing apparatus and electronic device |
WO2019187874A1 (en) * | 2018-03-28 | 2019-10-03 | ソニー株式会社 | Optical system for rigid scope, imaging device, and endoscopic system |
CN111971604A (en) * | 2018-03-28 | 2020-11-20 | 索尼公司 | Rigid mirror optical system, imaging device, and endoscope system |
US20210030263A1 (en) * | 2018-03-28 | 2021-02-04 | Sony Corporation | Rigid-scope optical system, imaging apparatus, and endoscope system |
EP3751325A4 (en) * | 2018-03-28 | 2021-04-07 | Sony Corporation | Optical system for rigid scope, imaging device, and endoscopic system |
JPWO2019187874A1 (en) * | 2018-03-28 | 2021-05-20 | ソニーグループ株式会社 | Optical system for rigid mirrors, imaging devices and endoscopic systems |
US11675204B2 (en) | 2018-03-28 | 2023-06-13 | Sony Corporation | Scope optical system, imaging apparatus, and endoscope system |
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