JPH07159687A - Optical system of amphibious camera - Google Patents
Optical system of amphibious cameraInfo
- Publication number
- JPH07159687A JPH07159687A JP5302842A JP30284293A JPH07159687A JP H07159687 A JPH07159687 A JP H07159687A JP 5302842 A JP5302842 A JP 5302842A JP 30284293 A JP30284293 A JP 30284293A JP H07159687 A JPH07159687 A JP H07159687A
- Authority
- JP
- Japan
- Prior art keywords
- optical system
- air
- lens
- photographing
- group
- 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.)
- Granted
Links
Landscapes
- Lenses (AREA)
- Structure And Mechanism Of Cameras (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、防水機構を施された空
気中或いは水中の何れにおいても撮影可能な水陸両用カ
メラの光学系に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical system for an amphibious camera which is waterproof and is capable of taking a picture in either the air or the water.
【０００２】[0002]
【従来の技術】水中での撮影は光の吸収，散乱等のた
め、近距離撮影が行われる場合が多く、従来の水陸両用
カメラの光学系には比較的広画角の単焦点レンズが用い
られてきた。又、従来の水陸両用カメラは空気中で使用
されているカメラを水中用ハウジング内に収容して使用
するもの、或いは、カメラ自体に防水機構を施したもの
が使用されてきた。このような従来の水陸両用カメラ
は、物体空間が空気で収差補正された撮影レンズ系の前
方に平板ガラスの防水窓を備えていた。この防水窓は，
前記撮影レンズ系に対する空気中での収差性能を損なわ
ないため、前記撮影レンズ系には空気中において収差性
能が保証されたレンズ系を用いることが可能であった。2. Description of the Related Art When shooting underwater, short-range shooting is often performed due to absorption and scattering of light, and a conventional single-lens lens with a relatively wide angle of view is used for the optical system of an amphibious camera. Has been. Further, as the conventional amphibious camera, a camera which is used in the air and is housed in an underwater housing, or a camera which is provided with a waterproof mechanism has been used. Such a conventional amphibious camera has a waterproof window made of flat glass in front of the taking lens system in which the object space is aberration-corrected by air. This waterproof window is
Since the aberration performance of the taking lens system in the air is not impaired, it is possible to use a lens system having a guaranteed aberration performance in the air for the taking lens system.
【０００３】しかしながら、水中における前記撮影レン
ズ系は、物体空間の屈折率の差によって、そのレンズ入
射面で種々の収差、特に倍率色収差及び歪曲収差が発生
し、水中での結像性能が低下してしまうという欠点を有
していた。又、物体空間が水である状況下で収差補正さ
れたレンズ系を空気中で使用した場合にも、レンズ入射
面で種々の収差が発生するため、逆に空気中での結像性
能が低下してしまうという問題があった。However, in the underwater photographing lens system, various aberrations, especially lateral chromatic aberration and distortion aberration occur on the entrance surface of the lens due to the difference in the refractive index of the object space, and the image forming performance underwater deteriorates. It had the drawback that it would end up. Also, when a lens system whose aberrations have been corrected is used in air when the object space is water, various aberrations occur on the lens entrance surface, which in turn reduces the imaging performance in air. There was a problem of doing.
【０００４】このような欠点を克服した従来例として
は、特開昭５６−１４２１１号公報に記載された光学系
が知られている。この光学系は、レンズ入射面の曲率中
心をレンズ全系の入射位置にほぼ一致させて軸外光線を
入射面にほぼ垂直に入射させることによって、物体空間
と像空間との屈折作用の変化を小さくし、発生する収差
を小さくすることを可能にしたものである。しかし、こ
の従来例にしても、物体平面がレンズの方向に凹面を向
けた球面状の虚像となるため、水中でプラスの像面湾曲
が大きく発生し、これを補正するのが困難であった。そ
のため、レンズ系中にその伸縮により像面特性が主とし
て変化し、他の収差には大きな変動が生じない少なくと
も一つの可変空間隔を設定することで、前記像面湾曲を
補正することを可能にしたものであった。An optical system described in Japanese Patent Laid-Open No. 56-14211 is known as a conventional example which overcomes such a drawback. This optical system changes the refraction effect between the object space and the image space by causing the center of curvature of the lens entrance surface to substantially coincide with the entrance position of the entire lens system and allowing off-axis rays to enter the entrance surface substantially perpendicularly. It is possible to reduce the aberrations that occur by reducing the aberration. However, even in this conventional example, since the object plane becomes a spherical virtual image with the concave surface facing the lens, a large positive field curvature occurs in water, which is difficult to correct. . Therefore, it is possible to correct the field curvature by setting at least one variable air gap in the lens system, which causes the image plane characteristics to change mainly due to the expansion and contraction thereof and does not cause a large change in other aberrations. It was something that was done.
【０００５】[0005]
【発明が解決しようとする課題】水中での撮影は近距離
撮影が行われる場合が多いため、殆どの水陸両用カメラ
の光学系には広角レンズが用いられてきた。しかし、陸
上での様々な撮影に応じて、広角の焦点距離域から望遠
の焦点距離域までの撮影に対応し得る高倍率なズームレ
ンズが撮影者に望まれる場面が多く、広角の焦点距離域
を使用した水陸両用カメラの光学系では、陸上での撮影
場面が極端に限定されてしまうという問題があった。
又、上記特開昭５６−１４２１１号公報に記載の光学系
のように、撮影レンズ入射面の曲率中心をレンズ全系の
入射瞳位置にほぼ一致させると、レンズ入射面が物体側
に曲率の強い凸面となり、広画角なレンズ程物体側のレ
ンズ径が大きくなってしまうため、当該光学系の小型化
には不利であるという問題もあった。A wide-angle lens has been used in the optical system of most amphibious cameras, since short-distance photography is often performed in underwater photography. However, there are many situations in which the photographer desires a high-power zoom lens that can be used for shooting from a wide-angle focal length range to a telephoto focal length range according to various shooting on land, and the wide-angle focal length range is wide. With the optical system of an amphibious camera using, there was a problem that the shooting scene on land was extremely limited.
Further, when the center of curvature of the entrance surface of the photographing lens is made to substantially coincide with the entrance pupil position of the entire lens system as in the optical system described in JP-A-56-14211, the entrance surface of the lens has a curvature toward the object side. Since the lens has a strong convex surface and the lens having a wider angle of view has a larger lens diameter on the object side, there is also a problem that it is disadvantageous for downsizing the optical system.
【０００６】そこで、本発明は、上記のような従来技術
の有する問題点に鑑み、高い結像性能を有し空気中，水
中を問わず撮影が可能であり、空気中では高倍率なズー
ムレンズ、一方、水中では比較的広画角なレンズを構成
し、且つ、前記レンズが大型化することがなく、簡単な
機構で空気中と水中との撮影状態を相互に切り換えるこ
とができる水陸両用カメラの光学系を提供することを目
的としている。In view of the above-mentioned problems of the prior art, the present invention has a high image forming performance and is capable of photographing in both air and water, and has a high magnification in the air. On the other hand, an amphibious camera that constitutes a lens with a relatively wide angle of view underwater, and that does not increase in size of the lens, and that can switch between shooting states in air and underwater with a simple mechanism. It is intended to provide the optical system of.
【０００７】[0007]
【課題を解決するための手段及び作用】上記目的を達成
するため、本発明による水陸両用カメラの光学系は、物
体空間が空気で収差補正された複数のレンズ群を有する
撮影光学系において、撮影時の物体空間が空気である場
合には前記複数のレンズ群の移動よって焦点距離可変の
変倍光学系を構成し、又、撮影時の物体空間が水である
場合には前記変倍光学系に発生する諸収差を補正し得る
ように前記複数のレンズ群を移動してある特定の焦点距
離に切り換えることにより水中撮影可能な光学系を構成
するようしたことを特徴としている。又、本発明の光学
系は、この光学系を物体空間が空気である場合の撮影状
態から物体空間が水である場合の撮影状態に切り換える
際、一度空気中での撮影が可能な広角端を構成した後に
水中での撮影が可能な焦点距離へと切り換わるようにし
たことを特徴としている。In order to achieve the above object, an optical system of an amphibious camera according to the present invention uses a photographing optical system having a plurality of lens groups in which an object space is aberration-corrected by air. When the object space at the time is air, a variable-magnification optical system having a variable focal length is constructed by the movement of the plurality of lens groups, and when the object space at the time of photographing is water, the variable-magnification optical system. It is characterized in that an optical system capable of underwater photography is configured by moving the plurality of lens groups to switch to a specific focal length so as to be able to correct various aberrations occurring in 1. Further, the optical system of the present invention is such that when the optical system is switched from a shooting state when the object space is air to a shooting state when the object space is water, a wide-angle end capable of shooting in air once is set. The feature is that after the configuration, it is switched to a focal length that enables shooting underwater.
【０００８】このように本発明の水陸両用カメラの光学
系は、物体空間が空気で収差補正された複数のレンズ群
から成り、当該レンズ群を移動させることによって焦点
距離可変のズームレンズを構成している。しかしなが
ら、物体空間が空気で収差補正されているレンズ系をそ
のまま水中で使用すると、レンズ入射面で倍率色収差及
び歪曲収差が発生することは前述の通りである。又、上
記従来例のように、レンズ入射面の曲率中心をレンズ系
の入射瞳位置に一致させると、レンズ入射面の曲率半径
が小さくなるため、比較的広画角な撮影レンズの場合、
最も物体側に配置されているレンズの径が大型化し、カ
メラの小型化には不利になっていた。As described above, the optical system of the amphibious camera of the present invention comprises a plurality of lens groups whose object space is aberration-corrected by air, and by moving the lens groups, a zoom lens having a variable focal length is constructed. ing. However, as described above, when the lens system in which the object space is corrected for aberration by air is used as it is in water, lateral chromatic aberration and distortion occur at the lens entrance surface. When the center of curvature of the lens entrance surface is made to coincide with the entrance pupil position of the lens system as in the above-mentioned conventional example, the radius of curvature of the lens entrance surface becomes smaller, so in the case of a relatively wide field angle photographing lens,
The lens disposed closest to the object side has a large diameter, which is disadvantageous for downsizing the camera.
【０００９】そこで、本発明は、比較的広画角な撮影レ
ンズを使用する場合でもカメラの小型化が達成できるよ
うにするため、レンズ入射面の曲率半径を小さくせずに
水中での倍率色収差及び歪曲収差を補正できるようにし
たものである。そのため、前記レンズ群において、変倍
には寄与せず、特に倍率色収差及び像面湾曲の特性が変
化し、他の収差の変動が少ないレンズ群を移動させるこ
とで、倍率色収差及び歪曲収差の特性をコントロール
し、物体空間の屈折率が変化しても良好な結像性能を維
持することができる。Therefore, according to the present invention, in order to make it possible to reduce the size of the camera even when using a taking lens having a relatively wide angle of view, the chromatic aberration of magnification in water can be achieved without reducing the radius of curvature of the lens entrance surface. And the distortion aberration can be corrected. Therefore, in the lens group, the characteristics of the chromatic aberration of magnification and the distortion aberration do not contribute to the zooming, and particularly the characteristics of the chromatic aberration of magnification and the field curvature are changed, and the other chromatic aberration is moved by moving the lens group. It is possible to maintain good imaging performance even if the refractive index of the object space changes.
【００１０】しかしながら、前記レンズ群を移動させる
ことで、倍率色と歪曲以外の収差が発生してしまう場合
がある。又、レンズ入射面が物体側に凸面を向けた曲率
である場合には、プラスの像面湾曲が大きく発生してし
まう。そこで、本発明の光学系は、これらの収差特性に
寄与しているレンズ群をも同時に移動させることで前記
諸収差をコントロールし、物体空間の屈折率が変化して
も良好な結像性能を維持できるようにすると共に、バッ
クフォーカスの変化による像面位置のズレを適切に保て
るように前記レンズ群を移動させている。従って、本発
明の光学系は、少なくとも一つ以上のレンズ群を移動で
きるように構成されることが好ましい。又、本発明の光
学系では、水中撮影時には焦点距離を固定するようにな
っている。これは、水中撮影時にレンズ系の全長を一定
に保持することで当該光学系の防水性を高めるためであ
る。この時、水中での当該光学系の焦点距離は、空気中
撮影時の広角端、或いは使用頻度の高い広角域の焦点距
離と等しくなっていることが好ましい。However, when the lens group is moved, aberrations other than the magnification color and distortion may occur. If the lens entrance surface has a curvature with a convex surface facing the object side, a large positive field curvature will occur. Therefore, the optical system of the present invention controls the various aberrations by moving the lens groups that contribute to these aberration characteristics at the same time, and provides good imaging performance even if the refractive index of the object space changes. The lens group is moved so as to be able to maintain it and to appropriately keep the shift of the image plane position due to the change of the back focus. Therefore, the optical system of the present invention is preferably configured so that at least one lens group can be moved. Further, in the optical system of the present invention, the focal length is fixed during underwater photography. This is to increase the waterproofness of the optical system by keeping the entire length of the lens system constant during underwater photography. At this time, it is preferable that the focal length of the optical system in water be equal to the focal length of the wide-angle end at the time of photographing in air or the wide-angle range that is frequently used.
【００１１】更に、光学系の小型化を達成し、且つ、水
中での良好な結像性能を維持するためには、撮影光学系
の広角端のレンズ入射面から入射瞳までの距離に対する
レンズ入射面の曲率半径は、以下の条件式を満足するよ
うに規定されることが好ましい。 ２．０＜｜ＲF ／Ａ｜ ・・・・（１） 但し、ＲF はレンズ入射面の曲率半径、Ａは撮影光学系
の水中撮影時におけるレンズ入射面から入射瞳までの距
離である。尚、上記条件式（１）の値は、その取り得る
値の範囲の下限を下回ると、水中撮影時にレンズ入射面
で発生する像面湾曲が変倍レンズ群の移動だけでは補正
しきれず、結像性能を良好に維持することが困難にな
る。Further, in order to achieve the downsizing of the optical system and to maintain the good imaging performance in water, the lens incidence with respect to the distance from the lens incidence surface at the wide-angle end of the photographing optical system to the entrance pupil. The radius of curvature of the surface is preferably defined so as to satisfy the following conditional expression. 2.0 <| R F / A | (1) where R F is the radius of curvature of the lens entrance surface, and A is the distance from the lens entrance surface to the entrance pupil during underwater imaging of the imaging optical system. . If the value of the conditional expression (1) is below the lower limit of the range of possible values, the field curvature generated on the lens entrance surface during underwater photography cannot be completely corrected by the movement of the variable power lens group. It becomes difficult to maintain good image performance.
【００１２】更に、本発明の光学系は、空気中での撮影
状態を構成したときのズームカム（回転レンズ環に設け
られた移動レンズ群の案内溝）の広角端の延長上に、水
中撮影時用のカムが設けられているため、水中での撮影
状態から空気中での撮影状態への切り換えがレンズ環の
回転のみによって行うことが可能になり、切り換えのた
めの特別な機構を設ける必要がない。従って、レンズ鏡
筒が大型化せず水中撮影状態への切り換えが簡単に行え
るようになっている。Further, the optical system of the present invention is used for underwater photography on the extension of the wide-angle end of the zoom cam (guide groove of the moving lens group provided on the rotary lens ring) when the photography state in air is configured. Since a cam for the camera is provided, it is possible to switch from the shooting state in water to the shooting state in air only by rotating the lens ring, and it is necessary to provide a special mechanism for switching. Absent. Therefore, the size of the lens barrel does not increase, and it is possible to easily switch to the underwater photographing state.
【００１３】[0013]
【実施例】以下、図示した実施例に基づき、本発明を詳
細に説明する。図１は本発明による光学系のレンズ構成
を示す断面図であり、（ａ）は空気中撮影時，（ｂ）は
水中撮影時の状態を夫々示した図である。図２は本発明
の光学系による空気中での広角端撮影時の収差曲線図、
図３は本発明の光学系による空気中での中間倍率撮影時
の収差曲線図、図５は本発明の光学系による空気中での
望遠端撮影時の収差曲線図である。図５は、本発明の光
学系による水中撮影時の収差曲線図である。図６は、本
発明の光学系の各レンズ群の移動する軌跡を示した図で
ある。図中、Ｇ1 〜Ｇ6 は夫々変倍時の可動群を示して
いる。The present invention will be described in detail below with reference to the illustrated embodiments. 1A and 1B are cross-sectional views showing a lens configuration of an optical system according to the present invention, wherein FIG. 1A is a diagram showing a state when photographing in air, and FIG. 1B is a diagram showing a state when photographing underwater. FIG. 2 is an aberration curve diagram at the time of wide-angle end photography in air by the optical system of the present invention,
FIG. 3 is an aberration curve diagram at the time of intermediate magnification photographing in air by the optical system of the present invention, and FIG. 5 is an aberration curve diagram at the telephoto end photographing in air by the optical system of the present invention. FIG. 5 is an aberration curve diagram during underwater photography by the optical system of the present invention. FIG. 6 is a diagram showing a locus of movement of each lens group of the optical system of the present invention. In the figure, G 1 to G 6 each represent a movable group during zooming.
【００１４】本発明による光学系は、図１に示したよう
に、物体側より順に、負のパワーを有する第一群
（Ｇ1 ）と、負のパワーを有する第二群（Ｇ2 ）と、正
のパワーを有する第三群（Ｇ3 ，Ｇ4 ，Ｇ5 及びＧ6 ）
とが配置されて構成されている。本発明の光学系は、物
体空間が空気である場合の広角端より望遠端への変倍に
際しては、図１（ａ）に示したように、第一群（Ｇ1 ）
が始め像方向（図の右側）へ移動し途中からは物体側
（図の左側）へ移動し、更に第三群（Ｇ3 ，Ｇ4 ，Ｇ5
及びＧ6 ）中のレンズ群がその焦点距離を減少させるよ
うに移動し、而も第三群全体の前側主点位置を物体側に
向かうように移動させて空気中での撮影が可能になる。
一方、物体空間が水である場合には、本発明の光学系
は、上記空気中での撮影状態における広角端の焦点距離
を維持しながら、レンズ入射面で発生する諸収差の補正
を行えるように各レンズ群を移動させて水中での撮影が
可能になる。尚、レンズ群Ｇ2 は主に像面湾曲，Ｇ3 は
主に倍率色収差，Ｇ6 は像面収差及び像面湾曲の補正に
寄与している。As shown in FIG. 1, the optical system according to the present invention comprises, in order from the object side, a first group (G 1 ) having negative power and a second group (G 2 ) having negative power. , A third group with positive power (G 3 , G 4 , G 5 and G 6 )
And are arranged. When the object space is air, the optical system of the present invention, when zooming from the wide-angle end to the telephoto end, as shown in FIG. 1A, the first group (G 1 )
First moves in the image direction (right side of the figure), and from the middle to the object side (left side of the figure), and further moves to the third group (G 3 , G 4 , G 5
And the lens group in G 6 ) is moved so as to reduce its focal length, and the front principal point position of the entire third group is moved toward the object side to enable photographing in air. .
On the other hand, when the object space is water, the optical system of the present invention can correct various aberrations occurring on the lens entrance surface while maintaining the focal length at the wide-angle end in the shooting state in the air. It is possible to shoot underwater by moving each lens group. The lens group G 2 mainly contributes to the field curvature, G 3 mainly contributes to the chromatic aberration of magnification, and G 6 contributes to the correction of the field aberration and the field curvature.
【００１５】更に、本発明の光学系は、図６に示したよ
うに、水中での撮影状態を構成したレンズ群は空気中で
の広角端の撮影状態を構成したレンズ群の移動の軌跡の
延長上にあるため、共通のズームカム上で簡単に前記二
状態の相互切り換えを行うことができる。Further, in the optical system according to the present invention, as shown in FIG. 6, the lens group constituting the photographing state in water is the locus of movement of the lens group constituting the photographing state at the wide angle end in the air. Because of the extension, the two states can be easily switched over on a common zoom cam.
【００１６】以下、本実施例の数値データを示す。 The numerical data of this embodiment are shown below.
【００１７】ｒ1 ＝134.7423 ｄ1 ＝2.200 ｎ1 ＝1.74320 ν1 ＝49.31 ｒ2 ＝27.0821 ｄ2 ＝7.000 ｒ3 ＝-435.7754 ｄ3 ＝1.900 ｎ3 ＝1.75700 ν3 ＝47.87 ｒ4 ＝48.3279 ｄ4 ＝0.150 ｒ5 ＝36.7495 ｄ5 ＝4.500 ｎ5 ＝1.84666 ν5 ＝23.78R 1 = 134.7423 d 1 = 2.200 n 1 = 1.74320 ν 1 = 49.31 r 2 = 27.0821 d 2 = 7.000 r 3 = -435.7754 d 3 = 1.900 n 3 = 1.75700 ν 3 = 47.87 r 4 = 48.3279 d 4 = 0.150 r 5 = 36.7495 d 5 = 4.500 n 5 = 1.84666 ν 5 = 23.78
【００１８】ｒ6 ＝131.8168 ｄ6 ＝12.5000(広角) ，5.0000 (中間) ，1.3000 (望
遠) ，0.4259 (水中) ｒ7 ＝62.2161 ｄ7 ＝2.000 ｎ7 ＝1.48749 ν7 ＝70.20 ｒ8 ＝44.1464 ｄ8 ＝36.8939(広角) ，13.3636(中間) ，1.4650 (望
遠) ，48.8530(水中) ｒ9 ＝45.5286 ｄ9 ＝1.500 ｎ9 ＝1.84666 ν9 ＝23.78 ｒ10＝21.5496 ｄ10＝6.500 ｎ10＝1.71300 ν10＝53.84R 6 = 131.8168 d 6 = 12.5000 (wide angle), 5.0000 (middle), 1.3000 (telephoto), 0.4259 (in water) r 7 = 62.2161 d 7 = 2.000 n 7 = 1.48749 ν 7 = 70.20 r 8 = 44.1464 d 8 = 36.8939 (wide angle), 13.3636 (intermediate), 1.4650 (telephoto), 48.8530 (in water) r 9 = 45.5286 d 9 = 1.500 n 9 = 1.84666 ν 9 = 23.78 r 10 = 21.5496 d 10 = 6.500 n 10 = 1.71300 ν 10 = 53.84
【００１９】ｒ11＝-97.3091 ｄ11＝0.1500 (広角) ，0.1500 (中間) ，0.1500 (望
遠) ，14.8945(水中) ｒ12＝25.2128 ｄ12＝4.850 ｎ12＝1.48749 ν12＝70.20 ｒ13＝∞ ｄ13＝2.8000 (広角) ，6.7678 (中間) ，12.2407(望
遠) ，1.8000 (水中) ｒ14＝∞ (絞り) ｄ14＝1.000 ｒ15＝-95.6768 ｄ15＝3.500 ｎ15＝1.80518 ν15＝25.43R 11 = -97.3091 d 11 = 0.1500 (wide angle), 0.1500 (middle), 0.1500 (telephoto), 14.8945 (in water) r 12 = 25.2128 d 12 = 4.850 n 12 = 1.48749 ν 12 = 70.20 r 13 = ∞ d 13 = 2.8000 (wide angle), 6.7678 (middle), 12.2407 (telephoto), 1.8000 (in water) r 14 = ∞ (aperture) d 14 = 1.000 r 15 = -95.6768 d 15 = 3.500 n 15 = 1.80518 ν 15 = 25.43
【００２０】ｒ16＝-17.3663 ｄ16＝1.400 ｎ16＝1.76200 ν16＝40.10 ｒ17＝39.8484 ｄ17＝16.8866(広角) ，9.6571 (中間) ，1.8000 (望
遠) ，15.3771(水中) ｒ18＝88.5160 ｄ18＝4.000 ｎ18＝1.53996 ν18＝59.57 ｒ19＝-39.4021 (非球面) ｄ19＝0.150 ｒ20＝-97.5417 ｄ20＝1.600 ｎ20＝1.80518 ν20＝25.43 ｒ21＝215.6004R 16 = -17.3663 d 16 = 1.400 n 16 = 1.76200 ν 16 = 40.10 r 17 = 39.8484 d 17 = 16.8866 (wide angle), 9.6571 (middle), 1.8000 (telephoto), 15.3771 (underwater) r 18 = 88.5160 d 18 = 4.000 n 18 = 1.53996 ν 18 = 59.57 r 19 = -39.4021 (aspherical surface) d 19 = 0.150 r 20 -97.5417 d 20 = 1.600 n 20 = 1.80518 ν 20 = 25.43 r 21 = 215.6004
【００２１】非球面係数 第１９面 Ｐ＝1.0000 Ｅ＝0.18670 ×10-4 ，Ｆ＝0.99813 ×10-8 Ｇ＝0.58878 ×10-9 ，Ｈ＝-0.35096×10-11 Ｉ＝0.15481 ×10-15 Aspherical surface coefficient 19th surface P = 1.0000 E = 0.186670 × 10 -4 , F = 0.99813 × 10 -8 G = 0.58878 × 10 -9 , H = -0.35096 × 10 -11 I = 0.15481 × 10 -15
【００２２】但し、本実施例において、ｒ1 ，ｒ2 ，・
・・・は各レンズ面の曲率半径、ｄ 1 ，ｄ2 ，・・・・
は各レンズの肉厚又は間隔、ｎ1 ，ｎ2 ，・・・・はｄ
線の屈折率、ν1 ，ν2 ・・・・はｄ線のアッベ数であ
る。尚、本実施例における非球面形状は、光軸方向の非
球面量をｘ，光軸からの高さをｈとしたとき、次式によ
って示される。 但し、ｒは近軸曲率半径、Ｅ，Ｆ，Ｇ，Ｈ，Ｉは夫々非
球面係数である。又、本実施例における上記条件式
（１）の値は、 ｜ＲF ／Ａ｜＝４．３ である。However, in this embodiment, r1, R2・ ・ ・
... is the radius of curvature of each lens surface, d 1, D2・ ・ ・ ・ ・ ・
Is the thickness or spacing of each lens, n1, N2, ... is d
Refractive index of line, ν1, Ν2... is the Abbe number of d line
It In addition, the aspherical surface shape in the present embodiment has a non-spherical shape in the optical axis direction.
Assuming that the spherical amount is x and the height from the optical axis is h,
Is shown.However, r is the paraxial radius of curvature, and E, F, G, H, and I are not
It is a spherical coefficient. In addition, the above conditional expression in the present embodiment
The value of (1) is | RF/A|=4.3.
【００２３】[0023]
【発明の効果】上述のように、本発明による水陸両用カ
メラの光学系は、空気中では高倍率なズームレンズ，一
方水中では比較的広画角の単焦点レンズとして高い結像
性能を維持しつつ、小型で且つ空気中での撮影状態と水
中での撮影状態との相互切り換えが簡単に行えるという
実用上重要な利点を有している。As described above, the optical system of the amphibious camera according to the present invention maintains a high image forming performance as a zoom lens having a high magnification in the air and a single focus lens having a relatively wide angle of view in the water. On the other hand, it has a practically important advantage that it is small and can easily switch between the shooting state in the air and the shooting state in the water.
【図１】本発明による光学系のレンズ構成を示す断面図
であり、（ａ）は空気中撮影時，（ｂ）は水中撮影時の
状態を夫々示した図である。FIG. 1 is a cross-sectional view showing a lens configuration of an optical system according to the present invention, FIG. 1 (a) is a diagram showing a state during photographing in air, and FIG. 1 (b) is a diagram showing a state during photographing underwater.
【図２】本発明の光学系による空気中での広角端撮影時
の収差曲線図である。FIG. 2 is an aberration curve diagram at the time of wide-angle end photography in air by the optical system of the present invention.
【図３】本発明の光学系による空気中での中間倍率撮影
時の収差曲線図である。FIG. 3 is an aberration curve diagram during intermediate magnification photographing in air by the optical system of the present invention.
【図４】本発明の光学系による空気中での望遠端撮影時
の収差曲線図である。FIG. 4 is an aberration curve diagram at the time of telephoto end photography in air by the optical system of the present invention.
【図５】本発明の光学系による水中撮影時の収差曲線図
である。FIG. 5 is an aberration curve diagram during underwater photography by the optical system of the present invention.
【図６】本発明の光学系の各レンズ群の移動の軌跡を示
した図である。FIG. 6 is a diagram showing a locus of movement of each lens group of the optical system of the present invention.
Ｇ1 第一群を構成しているレンズ群 Ｇ2 第二群を構成しているレンズ群 Ｇ3 ，Ｇ4 ，Ｇ5 ，Ｇ6 第三群を構成しているレンズ
群G 1 A lens group forming the first group G 2 A lens group forming the second group G 3 , G 4 , G 5 , G 6 A lens group forming the third group
Claims (2)
レンズ群を有する撮影光学系において、 撮影時の物体空間が空気である場合には前記複数のレン
ズ群の移動によって焦点距離可変の変倍光学系を構成
し、又、撮影時の物体空間が水である場合には前記変倍
光学系に発生する諸収差を補正し得るように前記複数の
レンズ群を移動してある特定の焦点距離に切り換えるこ
とにより水中撮影可能な光学系を構成するようにしたこ
とを特徴とする水陸両用カメラの光学系。1. A photographing optical system having a plurality of lens groups in which an object space is air and aberration correction is performed. When the object space at the time of photographing is air, the focal length is changed by movement of the plurality of lens groups. A specific focal point which constitutes a magnification optical system and which moves the plurality of lens groups so as to correct various aberrations generated in the variable power optical system when the object space at the time of photographing is water. An optical system for an amphibious camera characterized in that an optical system capable of underwater photography is configured by switching to a distance.
の撮影状態から物体空間が水である場合の撮影状態に切
り換える際、一度空気中での撮影が可能な広角端を構成
した後に水中での撮影が可能な焦点距離へと切り換わる
ようにしたことを特徴とする請求項１に記載の水陸両用
カメラの光学系。2. When the optical system is switched from a shooting state when the object space is air to a shooting state when the object space is water, a wide-angle end capable of shooting in air is once constructed and then the underwater is set. The optical system for an amphibious camera according to claim 1, wherein the optical system is adapted to switch to a focal length capable of shooting in the field.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP30284293A JP3431968B2 (en) | 1993-12-02 | 1993-12-02 | Optical system of amphibious camera |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP30284293A JP3431968B2 (en) | 1993-12-02 | 1993-12-02 | Optical system of amphibious camera |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH07159687A true JPH07159687A (en) | 1995-06-23 |
| JP3431968B2 JP3431968B2 (en) | 2003-07-28 |
Family
ID=17913757
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP30284293A Expired - Lifetime JP3431968B2 (en) | 1993-12-02 | 1993-12-02 | Optical system of amphibious camera |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3431968B2 (en) |
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| JP2001235679A (en) * | 2000-02-23 | 2001-08-31 | Canon Inc | Optical system, optical equipment having it, picture projector and image pickup unit |
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