JPH0387803A - Real image type variable power finder - Google Patents
Real image type variable power finderInfo
- Publication number
- JPH0387803A JPH0387803A JP1225565A JP22556589A JPH0387803A JP H0387803 A JPH0387803 A JP H0387803A JP 1225565 A JP1225565 A JP 1225565A JP 22556589 A JP22556589 A JP 22556589A JP H0387803 A JPH0387803 A JP H0387803A
- Authority
- JP
- Japan
- Prior art keywords
- lens group
- lens
- finder
- focal length
- positive
- 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
- 230000008859 change Effects 0.000 claims description 10
- 230000003287 optical effect Effects 0.000 claims description 8
- 230000014509 gene expression Effects 0.000 description 15
- 238000003384 imaging method Methods 0.000 description 13
- 230000004075 alteration Effects 0.000 description 12
- 238000010586 diagram Methods 0.000 description 4
- 206010010071 Coma Diseases 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
- 125000001475 halogen functional group Chemical group 0.000 description 2
- 230000001681 protective effect Effects 0.000 description 2
- 230000008901 benefit Effects 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 239000000428 dust Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000004907 flux Effects 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- JTJMJGYZQZDUJJ-UHFFFAOYSA-N phencyclidine Chemical compound C1CCCCN1C1(C=2C=CC=CC=2)CCCCC1 JTJMJGYZQZDUJJ-UHFFFAOYSA-N 0.000 description 1
- 210000001747 pupil Anatomy 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
- G02B15/144—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
- G02B15/144113—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)
- Viewfinders (AREA)
- Telescopes (AREA)
- Lenses (AREA)
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は変倍ファインダー、特に写真用カメラ、ビデオ
カメラ、電子スチルカメラ等に好適な高変倍、高倍率の
変倍ファインダーに関するものである。[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a variable magnification finder, particularly a variable magnification finder with a high magnification and high magnification suitable for photographic cameras, video cameras, electronic still cameras, etc. .
従来より、撮影系とファインダー系が別体に構成されて
いるカメラでは、撮影系が、変倍系の時は、撮影系の変
倍に伴ないファインダーの視野倍率も変化させることが
望ましく、また、ファインダー系の構成として所望の変
倍比が容易に得られるものが好ましい。Conventionally, in cameras where the photographing system and finder system are configured separately, when the photographing system is a variable magnification system, it is desirable to change the field of view magnification of the finder as the photographing system changes the magnification. It is preferable that the finder system has a structure that allows a desired variable power ratio to be easily obtained.
例えば、特開昭５３−６３０１４号公報では、物体側よ
り順に、負の屈折力の対物レンズと、正の屈折力の接眼
レンズより成る逆ガリレオ式ファインダーにお・いて、
対物レンズを正と負の屈折力の２つのレンズ群に分割し
、この内、負の屈折力のレンズ群を接眼レンズ側に移動
させて変倍を行なった変倍ファインダーを提案している
。しかしながら一般に逆ガリレオ式ファインンダーは、
対物レンズで形成された虚像のファインダー像を観察す
る構造であるために、ファインダー視野が眼の位置によ
って変化したり、またファインダー視野の輪郭が不明瞭
となる等の欠点がある。For example, in Japanese Patent Application Laid-Open No. 53-63014, in an inverted Galilean finder consisting of, in order from the object side, an objective lens with negative refractive power and an eyepiece lens with positive refractive power,
We have proposed a variable magnification finder in which the objective lens is divided into two lens groups with positive and negative refractive powers, and of these, the lens group with negative refractive power is moved to the eyepiece side to perform magnification change. However, in general, reverse Galilean finders are
Since the structure is such that a virtual viewfinder image formed by an objective lens is observed, there are drawbacks such as the viewfinder field of view changing depending on the position of the eye and the outline of the viewfinder field becoming unclear.
これに対して実像式ファインダーにおいては、正の屈折
力の対物レンズで形成された、実像のファインダー像を
観察する構造である為、実像位置に視野マスクを設ける
ことができ、ファインダー視野の輪郭が明瞭で、かつ眼
の位置が変化し“でもファインダー視野が変化しない等
の長所を有している。On the other hand, a real image finder has a structure in which a real finder image formed by an objective lens with positive refractive power is observed, so a field mask can be provided at the real image position, and the outline of the finder field of view is It has the advantage of being clear, and the viewfinder field of view does not change even if the position of the eye changes.
ところで実像式ファインダーにおいて、ファインダーの
視野倍率を変化させる技術として例えば、特開昭６１−
１５６０１８号公報等で提案されている。By the way, as a technique for changing the field of view magnification of a real image finder, for example, Japanese Patent Application Laid-Open No. 1986-
It has been proposed in Publication No. 156018 and the like.
第２図にそのレンズ断面図を示す。対物レンズ群中の第
２レンズ群・２３を物体側に移動して変倍を行ない、そ
れに伴なうファインダー視度の変化を第１レンズ群２２
を移動させることによって補正している。同図において
、２１は保護ガラス、２２は第１レンズ群、２３は第２
レンズ群、２４は第３レンズ群で、２２，２３．２４で
対物レンズ群を構成している。１５は２次結像レンズ、
１６はフィールドレンズ、１７は接眼レンズ、１８はア
イポイント、１９は１次結像面、２０は２次結像面であ
る。FIG. 2 shows a sectional view of the lens. The second lens group 23 in the objective lens group is moved toward the object side to change the magnification, and the accompanying change in finder diopter is measured by the first lens group 23.
This is corrected by moving the . In the figure, 21 is a protective glass, 22 is a first lens group, and 23 is a second lens group.
The lens group 24 is a third lens group, and 22, 23, and 24 constitute an objective lens group. 15 is a secondary imaging lens;
16 is a field lens, 17 is an eyepiece lens, 18 is an eye point, 19 is a primary imaging surface, and 20 is a secondary imaging surface.
しかしながら上述した公報が開示するファインダーの変
倍比は、２倍程度にとどまっている。However, the magnification ratio of the finder disclosed in the above-mentioned publication is only about 2 times.
近年、比較的小型化なカメラに於いても高変倍比を持っ
たズームレンズが搭載されることが要求されつつあるが
上述した公知例の変倍ファインダーでは、比較的に小型
化を達成できるものの十分な変倍比を持たせることが、
困難であった。In recent years, there has been a growing demand for relatively compact cameras to be equipped with zoom lenses with a high variable magnification ratio, but the above-mentioned known variable magnification finder can achieve a relatively small size. Having a sufficient magnification ratio of
It was difficult.
本発明の目的は、比較的高変倍比を維持しつつ小型で、
良好な光学性能を持った実像式の変倍ファインダーを提
供することにある。The purpose of the present invention is to maintain a relatively high variable power ratio while maintaining a small size.
The object of the present invention is to provide a real image variable magnification finder with good optical performance.
物体側より順に、正の屈折力の第１レンズ群、負の屈折
力の第２レンズ群、正の屈折力の第３レンズ群の少なく
とも３つのレンズ群よりなり全体として正の屈折力を有
する対物レンズ部と前記対物レンズ部の後方に配置され
た、正の屈折力を有する接眼レンズ部とにより構成され
る変倍ファインダーにおいて、前記第２レンズ群を接眼
側に移動させることによって広角側から望遠側への変倍
を行ない、それに伴なうファインダー視度の変化を前記
第３レンズ群を移動させることによって補正し、前記対
物レンズ部の広角端の焦点距離をＦＷ望遠端の焦点距離
をＦ７第１レンズ群の焦点距離をｆ’ｓ第２レンズ群の
焦点距離をｆｆｆ、接眼レンズの焦点距離をｆ、第３レ
ンズ群中、最も物体側に配置されたレンズの物体側のレ
ンズ面の曲率半径をＲＡ接眼側のレンズ面の曲率半径を
Ｒ８とした時、
１＜ ｆ ｒ ／ Ｆア＜２．５ ・・・（１
）ｔ＜ｌ ｆａ／Ｆｗ ｜＜２．５ ・・・（２）
但しｆｎ＜Ｏ
ｏ＜ ｌ Ｒ，／ＲＡｌ ＜０．５ ・・・（３）
０、２＜Ｆｗ ／ ｆ 、 ＜ １ ・・・（
４）なる条件式を満足させることにある。Consists of at least three lens groups, in order from the object side, a first lens group with positive refractive power, a second lens group with negative refractive power, and a third lens group with positive refractive power, and has positive refractive power as a whole. In a variable magnification finder that includes an objective lens section and an eyepiece section having positive refractive power and arranged behind the objective lens section, by moving the second lens group toward the eyepiece side, The magnification is changed toward the telephoto side, and the accompanying change in the finder diopter is corrected by moving the third lens group, and the focal length at the wide-angle end of the objective lens section is changed to the focal length at the FW telephoto end. F7 The focal length of the first lens group is f's The focal length of the second lens group is fff The focal length of the eyepiece is f The lens surface on the object side of the lens placed closest to the object side in the third lens group When the radius of curvature of the lens surface on the eyepiece side of RA is R8, 1< f r / F a < 2.5 (1
)t<l fa/Fw |<2.5...(2)
However, fn<O o< l R,/RA1 <0.5...(3)
0, 2<Fw/f, <1...(
4) The purpose is to satisfy the following conditional expression.
第１図は本発明における実像式変倍ファインダーの実施
例を示す概略図である。同図において、１１．１２，１
３，１４．は順に各々正の屈折力の第１レンズ群、負の
屈折力の第２レンズ群、正の屈折力の第３レンズ群、正
の屈折力の第４レンズ群であり、１１，１２，１３．１
４により全体として正の屈折力の対物レンズを構成して
いる。１５は２次結像レンズ、１６はフィールドレンズ
、１７は接眼レンズ１８はアイポイント、１９は一次結
像面、２０は２次結像面である。広角端から望遠端への
変倍に際しては対物レンズ中の第２レンズ群１２が、接
眼側に移動すると共に、第３レンズ群１３が、物体側に
凸の軌跡を描くことにより、視度変化のない変倍を行な
っている。ここで第１及び第４レンズ群１１及び１４は
変倍に際して固定であり、特に第１レンズ群１１を変倍
に際して固定して密閉構造をしやすくして、仮に、保護
ガラスを前方に配置しなくても第１レンズ群１１と第２
レンズ群１２との間に、ゴミ等が侵入する事を防止して
いる。また第４１ノンズ群１４は第１〜第３レンズ群の
合成焦点面近傍に配置させて、第１〜第３レンズ群を通
過した光束を発散しないように光軸方向に集光する所謂
フィールドレンズの機能を備えさせている。FIG. 1 is a schematic diagram showing an embodiment of a real image variable magnification finder according to the present invention. In the same figure, 11.12,1
3,14. are the first lens group with positive refractive power, the second lens group with negative refractive power, the third lens group with positive refractive power, and the fourth lens group with positive refractive power, and 11, 12, 13 .1
4 constitutes an objective lens with positive refractive power as a whole. 15 is a secondary imaging lens, 16 is a field lens, 17 is an eyepiece 18 is an eye point, 19 is a primary imaging surface, and 20 is a secondary imaging surface. When changing the magnification from the wide-angle end to the telephoto end, the second lens group 12 in the objective lens moves toward the eyepiece side, and the third lens group 13 draws a convex locus toward the object side, thereby changing the diopter. The magnification is changed without . Here, the first and fourth lens groups 11 and 14 are fixed during zooming, and in particular, the first lens group 11 is fixed during zooming to facilitate a sealed structure, and if a protective glass is placed in front. Even without the first lens group 11 and the second lens group
This prevents dust and the like from entering between the lens group 12 and the lens group 12. The 41st non-lens group 14 is a so-called field lens that is arranged near the synthetic focal plane of the first to third lens groups and condenses the light beams that have passed through the first to third lens groups in the optical axis direction so as not to diverge. It is equipped with the following functions.
上述した構成によって被写体からの光束は第１〜第４レ
ンズ群を通過した後１次結像面１９上で、上下左右が反
転した状態で結像する。次に１次結像面１９の後方に配
置された２次結像レンズ１５とフィールドレンズ１６に
より１次結像面で上下左右が反転した被写体像を２次結
像面２０上に、正規な状態・で再結像させ、さらにこの
２次結像面２０上の被写体像を接眼レンズ１７を介して
アイポイント１８で観察される。With the above-described configuration, the light beam from the subject passes through the first to fourth lens groups and then forms an image on the primary imaging plane 19 with the upper, lower, right, and left sides reversed. Next, a secondary imaging lens 15 and a field lens 16 placed behind the primary imaging plane 19 convert the subject image, which has been vertically and horizontally inverted on the primary imaging plane, onto the secondary imaging plane 20 into a regular image. The object image on the secondary imaging plane 20 is observed at the eyepoint 18 through the eyepiece 17.
なお、近年急速に発展しつつあるスチルビデオカメラ等
の撮影画面サイズが比較的小さい撮像素子を使用した場
合に、撮影レンズは比較的大きくせずに高倍のズーム化
、更には、近距離まで撮影することが容易となる。この
結果従来と異なり特に望遠撮影時であって、しかも近距
離被写体に対し撮影する場合、外部ファインダーの視度
が十分に合わないといった問題が生ずる。本実施例にお
いてはこのような近距離撮影を行う場合には対物レンズ
系の第１レンズ群をフォーカスレンズとして光軸方向に
繰出すことによって容易に近距離被写体に対する視度ず
れを補正している。In addition, when using an image sensor with a relatively small shooting screen size, such as a still video camera that has been rapidly developing in recent years, it is possible to achieve high zoom magnification and even shoot at close range without making the shooting lens relatively large. It becomes easier to do so. As a result, unlike the conventional method, a problem arises in that the diopter of the external viewfinder is not sufficiently adjusted, especially when photographing a close-up object during telephoto shooting. In this embodiment, when performing such close-range photography, the first lens group of the objective lens system is extended in the optical axis direction as a focus lens, thereby easily correcting the diopter deviation for the close-range subject. .
次に本発明の実像式のファインダーに於いて高変倍でし
かも光学性能の良いファインダー像を得るには、対物レ
ンズ部の広角端の焦点距離をＦ ’ＩＩ ＋望遠端の焦
点距離をＦＴｓ第１レンズ群の焦点距離をｆＩｓ第２レ
ンズ群の焦点距離をｆａｘ接眼レンズの焦点距離をｆｌ
、第３レンズ群中最も物体側に配置されたレンズの物体
側のレンズ面の曲率半径をＲＡ１接眼側のレンズ面の曲
率半径をＲＢとした時、
１＜ｆ ｒ／Ｆ７＜２．５ ・ （１）１＜
ｌ ｆ ＊／Ｆ−１＜２．５ ・・・（２）但し
ｆａ＜０
０＜ＪＲ，／ＲＡ Ｉ＜０．５ ・・・（３）ｏ、
２くＩＦＷ／ｆ、｜＜１ ・・・（４）なる前述
した条件を満足させると良い。で上記条件式の技術的意
味について説明する。条件式（１）は、第１レンズ群の
焦点距離に関する条件で、上限値を越えると十分な変倍
比を稼ぐことが困難になってくるとともに、ファインダ
ー全長が長くなってくるので好ましくない。一方で下限
値を越えると、像面湾曲が補正過剰となり、また望遠側
で球面収差が補正不足となり好ましくない。Next, in order to obtain a finder image with high zoom ratio and good optical performance in the real image finder of the present invention, the focal length at the wide-angle end of the objective lens section must be set to F'II + the focal length at the telephoto end to FTs. The focal length of the first lens group is fIs The focal length of the second lens group is fax The focal length of the eyepiece is fl
, When the radius of curvature of the lens surface on the object side of the lens disposed closest to the object side in the third lens group is RA1, and the radius of curvature of the lens surface on the eyepiece side is RB, 1<fr/F7<2.5 ・(1) 1<
l f */F-1<2.5...(2) However
fa<0 0<JR, /RA I<0.5...(3) o,
2×IFW/f, |<1 (4) It is preferable to satisfy the above-mentioned condition. The technical meaning of the above conditional expression will be explained below. Conditional expression (1) is a condition regarding the focal length of the first lens group, and if it exceeds the upper limit, it becomes difficult to obtain a sufficient variable power ratio and the overall length of the finder becomes long, which is not preferable. On the other hand, if the lower limit is exceeded, the curvature of field will be overcorrected and spherical aberration will be undercorrected at the telephoto side, which is not preferable.
又この条件式（１）はファインダーの物体距離による視
度変化を補正する為に上述した通りに第１レンズ群を移
動させた場合に関するもので条件式の上限値を越えると
、視度変化を補正する為の第１レンズ群の移動量が大き
くなり、このためファインダー全長及び第１レンズ径が
大きくなり好ましくない。また条件式（２）は、ファイ
ンダー系のコンパクト化に関するものであり、条件式の
上限値を越えると、変倍による第２群の移動量が太き（
なり好ましくない。また下限値を越えると、コンパクト
化には有利となるが広角側で歪曲収差が補正不足となり
好ましくない。Also, this conditional expression (1) relates to the case where the first lens group is moved as described above in order to correct the diopter change due to the object distance of the finder, and if the upper limit of the conditional expression is exceeded, the diopter change will be corrected. The amount of movement of the first lens group for correction becomes large, which increases the overall length of the finder and the diameter of the first lens, which is undesirable. Furthermore, conditional expression (2) relates to compactness of the finder system, and if the upper limit of the conditional expression is exceeded, the amount of movement of the second group due to zooming becomes large (
I don't like it. If the lower limit is exceeded, it is advantageous for compactness, but distortion aberration will be insufficiently corrected on the wide-angle side, which is undesirable.
次に条件式（３）は、主にコマ収差の補正に関するもの
で、条件式の下限値を越えると望遠側で上側光束による
ハローの発生が大きくなり、また上限値を越えると広角
側で下方性のコマ収差が発生し好ましくない。Next, conditional expression (3) is mainly related to the correction of coma aberration; if the lower limit of the conditional expression is exceeded, halo generation due to the upper light beam will increase at the telephoto side, and if the upper limit is exceeded, the halo will be lower at the wide-angle side. This is undesirable because it causes comatic aberration.
一般にファインダー系において、コマ収差が残存してい
ると観察者が眼を振った場合、像のゆらぎとなって表わ
れてくるので、本実施例では前述の如くレンズ形状を特
定することにより、特にコマ収差を良好に補正し、多少
眼を振っても、ゆらぎのない良好なるファインダー像を
得ている。Generally, in a finder system, if coma aberration remains, it will appear as image fluctuation when the observer shakes his or her eyes, so in this example, by specifying the lens shape as described above, Comatic aberration is well corrected, and even if you shake your eyes a little, you can still get a good viewfinder image with no fluctuations.
条件式（４）は、対物レンズと接眼レンズの焦点距離の
比に関する条件式である。条件式の上限値を越えると、
アイポイントを長くすることができず、また諸収差、特
に像面湾曲が著しく悪化する為好ましくない。条件式の
下限値を越えるとアイポイントを長く設定することがで
きるもののファインダー全長が長くなる為好ましくない
。Conditional expression (4) is a conditional expression regarding the ratio of the focal lengths of the objective lens and the eyepiece lens. If the upper limit of the conditional expression is exceeded,
This is not preferable because the eye point cannot be made long and various aberrations, especially curvature of field, are significantly worsened. If the lower limit of the conditional expression is exceeded, the eye point can be set longer, but the overall length of the finder becomes longer, which is not preferable.
−古本発明において、簡易な構成にもかかわらず、変倍
における収差変動を少なくし、全変倍範囲にわたり、良
好なる収差補正を達成する為には、対物レンズ群中の第
１レンズ群を１枚の正レンズ、第２レンズ群を２枚の負
レンズで構成した場合であってそして特に高変倍比を望
む場合は第２レンズの物体側のレンズを接眼側に凹の負
レンズ、接眼側のレンズを物体側に強い凹面を向けた負
レンズの２枚のレンズ、第３レンズ群を少なくとも２枚
の正レンズ、で構成するとともに接眼レンズの物体側の
レンズを接眼側に強い凸面を向けた正レンズ、接眼側の
レンズを両凸の正レンズの２枚のレンズ、第４レンズ群
を物体側に強い凸面を向けた１枚の正レンズで構成する
ことが好ましい。また、本発明においては、特に歪曲収
差を補正する為に第１レンズ群のいずれかの面を非球面
例１〜３のレンズ断面図を示す。数値実施例において、
Ｒｉは光束の進行順に第ｉ番目の光学要素の曲率半径、
Ｄｉは第ｉ番目のレンズ厚及び空気間隔、Ｎｉ、Ｖｉは
第ｉ番目の光学要素の屈折率及びアツベ数である。- In the old invention, despite the simple configuration, in order to reduce aberration fluctuations during zooming and achieve good aberration correction over the entire zooming range, the first lens group in the objective lens group must be When the second lens group is composed of two negative lenses and a particularly high zoom ratio is desired, the object side lens of the second lens is placed on the eyepiece side, and a concave negative lens is placed on the eyepiece side. The side lens consists of two negative lenses with a strongly concave surface facing the object side, the third lens group consists of at least two positive lenses, and the object side lens of the eyepiece has a strongly convex surface facing the eyepiece. It is preferable that the eyepiece side lens be composed of two biconvex positive lenses, and the fourth lens group be composed of one positive lens with a strongly convex surface facing the object side. Further, in the present invention, lens cross-sectional views of examples 1 to 3 in which one of the surfaces of the first lens group is aspheric are shown in order to correct distortion aberration in particular. In numerical examples,
Ri is the radius of curvature of the i-th optical element in the order of progression of the light flux,
Di is the i-th lens thickness and air spacing, and Ni and Vi are the refractive index and Abbe number of the i-th optical element.
また実施例中の＊印は非球面を表わし、その非球面系数
は、非球面の形状を近軸曲率半径Ｒａ。Further, the mark * in the examples represents an aspherical surface, and the aspherical surface coefficient is the paraxial radius of curvature Ra of the shape of the aspherical surface.
光軸上の光束の進行方向をＸ軸、Ｘ軸と垂直方向をＹ軸
とした時、
で表わした場合のＢ、Ｃ，Ｄ・・・で示す。When the traveling direction of the light beam on the optical axis is the X-axis, and the direction perpendicular to the X-axis is the Y-axis, these are shown as B, C, D, etc.
また前述の各条件式と数値実施例における諸数値との関
係を表−１に示す。Further, Table 1 shows the relationship between each of the above-mentioned conditional expressions and various numerical values in the numerical examples.
数値実施例１
２３
＊印は非球面
Ｅ＝
５゜
７９８Ｘ１０−ＩＯ
Ｅ＝
１゜
９４３Ｘ１０−’
数値実施例２
＊印は非球面
」
８゜
２６Ｘ１０
数値実施例３
Ｒｉ
Ｒｉ
１１゜
７１
−４８． ９４
ν ｌ
＊印は非球面
Ｃ＝ ３゜
Ｄ＝−７゜
Ｅ＝ ６゜
１２ Ｘｌ０−’
６０４Ｘ１０−’
２８Ｘ１０
数値実施例４
Ｒｉ
１
−１４４． ９３
−２０． ７０９
１．８
６
１゜
広角端 中 間 望遠端
Ｄ ２ １．３８３ ５．８４２ １４．
１２３Ｄ ６ １４．２４ ８．６０６
１．６４３ｒ）１０ １２．３７７ １３．５５
１ １２．２３３＊印は非球面
Ｃ＝ １゜
Ｄ＝−４゜
８５８Ｘ１０ ＠
４３７ｘｌＯ−”
〔発明の効果〕
以上説明した様に、本発明によれば、広角端から望遠端
への変倍に際して、第１．第４レンズ群を固定とし、第
２レンズ群を接眼側に移動させると共に、第３レンズ群
をファインダー視度変化補正の為移動させ、さらに各レ
ンズを形状及び条件式で規定することにより、変倍比３
〜３．５倍と高変倍比であるにもかかわらず全ズーム域
で良好に収差補正を行なうことができる。Numerical Example 1 23 *mark is aspherical surface E=5°798X10-IO E=1°943X10-' Numerical Example 2 *marked is aspherical surface" 8°26X10 Numerical Example 3 Ri Ri 11°71 -48. 94 ν l *mark is aspherical surface C = 3°D = -7°E = 6°12 Xl0-'604X10-' 28X10 Numerical Example 4 Ri 1 -144. 93-20. 709 1.8 6 1° Wide-angle end Intermediate Telephoto end D 2 1.383 5.842 14.
123D 6 14.24 8.606
1.643r) 10 12.377 13.55
1 12.233 * mark is an aspherical surface C = 1°D = -4°858X10 @ 437xlO-” [Effects of the Invention] As explained above, according to the present invention, when changing the magnification from the wide-angle end to the telephoto end, , 1. The fourth lens group is fixed, the second lens group is moved to the eyepiece side, and the third lens group is moved to correct for finder diopter change, and each lens is defined by shape and conditional expression. By this, the magnification ratio is 3.
Despite the high zoom ratio of ~3.5x, aberrations can be corrected well over the entire zoom range.
第１図は本発明の一実施例の概略図。
第２図は従来技術の説明図。
第３図〜第６図は各々本発明の数値実施例１〜３の断面
図。
第７図〜第１０図は、各々本発明の数値実施例１〜３の
諸収差図。
図中１１は第１レンズ群、１２は第２レンズ群、１３は
第３レンズ群、１４は第４レンズ群、１６はフィールド
レンズ、２０は２次結像面、１７は接眼レンズ、１８は
瞳、ＡＭはメリデイオナル像面、ＡＳはサジタル像であ
る。
（づｉオフブタ−）
（テ？才か）
（〃）
（子１才）９−）
（千ンオヅター）
（’／、 ）
（ディオヅダー）
（看わＣ）
（”／、）
（テ′ｉｔ勺−）
（罰オプター）
（６１０ン
（テｊオプター２
（テ１オブグーン
（Ｄ／−）
（−ｆ４メ′プターン
（テ？オゲター）
（’／−）
（う１じｒブダー）
（９１オプター）
（’／−）
−ＩＪＷＩ／ 舌欠ＦＩＥＪｑヌ［Ｌ！σσ−！００
４％点頓見
２ｍ −，５−ρθ
歪曲１１差
５・−一
つ
［
色ＩＩズ舊
ヨ（Ｃ）
３ ｚｏｏ −ｓ・θ０歪曲ｕｚ五ｓ、ｏ。FIG. 1 is a schematic diagram of an embodiment of the present invention. FIG. 2 is an explanatory diagram of the prior art. 3 to 6 are cross-sectional views of numerical examples 1 to 3 of the present invention, respectively. 7 to 10 are aberration diagrams of numerical examples 1 to 3 of the present invention, respectively. In the figure, 11 is the first lens group, 12 is the second lens group, 13 is the third lens group, 14 is the fourth lens group, 16 is the field lens, 20 is the secondary imaging plane, 17 is the eyepiece, and 18 is the The pupil, AM, is a meridional image plane, and AS is a sagittal image. (Zi off pig) (te? old?) (〃) (child 1 year old) 9-) (1000 oz.) ('/, ) (diozuda) (watch C) (''/,) (te'it 勺-) (punishment opter) (610n(tej opter 2) (te 1 of goon(D/-) ('/-) -IJWI/ tongue missing FIEJqnu [L!σσ-!00
4% point Tonmi 2m -, 5 - ρθ Distortion 11 difference 5 - one [Color II zu 舊 YO (C) 3 zooo -s θ0 distortion uz 5 s, o.
Claims (4)
の屈折力の第２レンズ群、正の屈折力の第３レンズ群の
少なくとも３つのレンズ群よりなり全体として正の屈折
力を有する対物レンズ部と前記対物レンズ部の後方に配
置された、正の屈折力を有する接眼レンズ部とにより構
成される変倍ファインダーにおいて、前記第２レンズ群
を接眼側に移動させることによって広角側から望遠側へ
の変倍を行ない、それに伴なうファインダー視度の変化
を前記第３レンズ群を移動させることによって補正し、
前記対物レンズ部の広角端の焦点距離をＦ＿Ｗ望遠端の
焦点距離をＦ＿Ｔ第１レンズ群の焦点距離をｆ＿ I 、
第２レンズ群の焦点距離をｆ＿II接眼レンズの焦点距離
をｆ＿ｅ、第３レンズ群中、最も物体側に配置されたレ
ンズの、物体側のレンズ面の曲率半径をＲ＿Ａ接眼側の
レンズ面の曲率半径をＲ＿Ｂとした時 １＜ｆ＿ I ／Ｆ＿Ｔ＜２．５・・・（１） １＜｜ｆ＿II／Ｆ＿Ｗ＜２．５・・・（２）但しｆ＿I
I＜０ ０＜｜Ｒ＿Ｂ／Ｒ＿Ａ｜＜０．５・・・（３）０．２＜
Ｆ＿Ｗ／ｆ＿ｅ＜１・・・（４）なる条件を満足するこ
とを特徴とする実像式の変倍ファインダー。(1) Consisting of at least three lens groups in order from the object side: the first lens group with positive refractive power, the second lens group with negative refractive power, and the third lens group with positive refractive power, and has positive refraction as a whole. In a variable magnification finder composed of an objective lens section having a refractive power and an eyepiece section having a positive refractive power disposed behind the objective lens section, by moving the second lens group toward the eyepiece side. Changing the magnification from the wide-angle side to the telephoto side, and correcting the change in finder diopter caused by this by moving the third lens group,
The focal length at the wide-angle end of the objective lens section is F_W, the focal length at the telephoto end is F_T, the focal length of the first lens group is f_I,
The focal length of the second lens group is f_II The focal length of the eyepiece is f_e The radius of curvature of the lens surface on the object side of the lens placed closest to the object side in the third lens group is R_A The curvature of the lens surface on the eyepiece side When the radius is R_B, 1<f_ I /F_T<2.5...(1) 1<|f_II/F_W<2.5...(2) However, f_I
I<0 0<|R_B/R_A|<0.5...(3)0.2<
A real image variable magnification finder characterized by satisfying the following condition: F_W/f_e<1 (4).
距離物体に対するファインダーの視度ずれを補正するこ
とを特徴とする特許請求の範囲第１項記載の実像式の変
倍ファインダー。(2) A real-image variable magnification finder according to claim 1, wherein the first lens group is extended in the optical axis direction to correct a diopter deviation of the finder with respect to a close object.
群は少なくとも１枚の負レンズ、第３レンズ群は２枚の
正レンズにより構成したことを特徴とする特許請求の範
囲第１項記載の実像式の変倍ファインダー。(3) The first lens group is composed of one positive lens, the second lens group is composed of at least one negative lens, and the third lens group is composed of two positive lenses. The real image variable magnification finder described in item 1.
れかの面を非球面としたことを特徴とする特許請求の範
囲第１項記載の実像式の変倍ファインダー。(4) A real image variable magnification finder according to claim 1, wherein in the objective lens section, one of the surfaces of the first lens group is an aspherical surface.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1225565A JP2899017B2 (en) | 1989-08-31 | 1989-08-31 | Real image type magnification finder |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1225565A JP2899017B2 (en) | 1989-08-31 | 1989-08-31 | Real image type magnification finder |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0387803A true JPH0387803A (en) | 1991-04-12 |
| JP2899017B2 JP2899017B2 (en) | 1999-06-02 |
Family
ID=16831297
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1225565A Expired - Fee Related JP2899017B2 (en) | 1989-08-31 | 1989-08-31 | Real image type magnification finder |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2899017B2 (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH08114742A (en) * | 1994-08-23 | 1996-05-07 | Asahi Optical Co Ltd | Optical system for composite camera |
| US5774275A (en) * | 1994-08-30 | 1998-06-30 | Canon Kabushiki Kaisha | Variable magnification viewfinder |
| KR100382006B1 (en) * | 1995-12-30 | 2003-08-30 | 삼성테크윈 주식회사 | Real-image zoom finder |
| CN110244450A (en) * | 2019-07-19 | 2019-09-17 | 杭州有人光电技术有限公司 | A kind of big visual field eyepiece optical system of virtual reality device |
| CN110412759A (en) * | 2019-08-21 | 2019-11-05 | 杭州图谱光电科技有限公司 | A kind of zoomable electronic eyepiece adapter of limited remote conjugate distance microscope |
-
1989
- 1989-08-31 JP JP1225565A patent/JP2899017B2/en not_active Expired - Fee Related
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH08114742A (en) * | 1994-08-23 | 1996-05-07 | Asahi Optical Co Ltd | Optical system for composite camera |
| US5774275A (en) * | 1994-08-30 | 1998-06-30 | Canon Kabushiki Kaisha | Variable magnification viewfinder |
| KR100382006B1 (en) * | 1995-12-30 | 2003-08-30 | 삼성테크윈 주식회사 | Real-image zoom finder |
| CN110244450A (en) * | 2019-07-19 | 2019-09-17 | 杭州有人光电技术有限公司 | A kind of big visual field eyepiece optical system of virtual reality device |
| CN110244450B (en) * | 2019-07-19 | 2021-05-11 | 杭州有人光电技术有限公司 | Large-view-field eyepiece optical system of virtual reality equipment |
| CN110412759A (en) * | 2019-08-21 | 2019-11-05 | 杭州图谱光电科技有限公司 | A kind of zoomable electronic eyepiece adapter of limited remote conjugate distance microscope |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2899017B2 (en) | 1999-06-02 |
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