JPS59159118A - Rear focus type lens - Google Patents
Rear focus type lensInfo
- Publication number
- JPS59159118A JPS59159118A JP58033442A JP3344283A JPS59159118A JP S59159118 A JPS59159118 A JP S59159118A JP 58033442 A JP58033442 A JP 58033442A JP 3344283 A JP3344283 A JP 3344283A JP S59159118 A JPS59159118 A JP S59159118A
- Authority
- JP
- Japan
- Prior art keywords
- lens group
- focusing
- lens
- stop
- time
- 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
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
- G02B15/143—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective having three groups only
- G02B15/1431—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective having three groups only the first group being positive
- G02B15/143105—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective having three groups only the first group being positive arranged +-+
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Lenses (AREA)
Abstract
Description
【発明の詳細な説明】
くはカラービデオカメラ等のカラーカメラに適したリア
７オーカス型のレンズ又はズームレンズに関するもので
ある。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rear 7 orcus type lens or zoom lens suitable for a color camera such as a color video camera.
一般に、色分解プリズム、ストライブフィルター、ある
いはモザイクフィルター等の色分解光学系を有するカラ
ーカメラについては、良好な色再現特性を得るために、
射出瞳距離が大きい（望ましくは２００〜３００ｉｍ以
上理想的には無限遠）ことと共に、その距離が変化しな
いことがよいとされている。また実用上の必要性から構
成されることのある射出棺距離の短かいものについても
色再現性の電気的補正を行なう上で射出瞳距離の変化し
ないことがよい。In general, in order to obtain good color reproduction characteristics for color cameras that have color separation optical systems such as color separation prisms, stripe filters, or mosaic filters,
It is said that it is good that the exit pupil distance is large (preferably 200 to 300 mm or more, ideally infinity) and that the distance does not change. Furthermore, even for short exit pupil distances which may be constructed due to practical necessity, it is preferable that the exit pupil distance does not change when electrically correcting color reproducibility.
ところが、絞シよυ像側に位置するレンズ群をフォーカ
シングのために移動させる形式の所謂リアフォーカス型
レンズが、重量の点やフォーカシング用の移動レンズと
カメラ本体の距離が短がいためメカ的信号伝達の上で有
利であるという理由から、近時において実用に供される
傾向にある。However, so-called rear-focus lenses, in which a lens group located on the image side of the aperture is moved for focusing, cannot receive mechanical signals due to their weight and the short distance between the moving lens for focusing and the camera body. Recently, it has been put into practical use because it is advantageous in terms of communication.
しかしこの形式のリアフォーカス型レンズは絞シよシ像
側のレンズ群が移動する結果として通常射出瞳位置が変
化し、色分解光学系を有するカラーカメラでは色再現性
の点で問題が生ずる。However, in this type of rear focus lens, the exit pupil position usually changes as a result of the movement of the lens group on the image side across the aperture, which causes a problem in color reproducibility in a color camera having a color separation optical system.
この問題はズーミングのだめの移動レンズ群を含むズー
ムレンズにおいても同様である〇そとで本発明において
は、絞ｉ］像側に７オーカシングのだめの移動レンズ群
を有するリアフォーカス型レンズつき、射出瞳位置がフ
ォーカシングによっても変化しないようにすることを目
的としてなされたものである。而してこの目的を達成す
るだめの本発明の要旨とするところは、フォーカシング
のだめのレンズ群よシ物体側に絞シを配設し、この絞り
をフォーカシング時の射出瞳位置が常に一定位置にある
よう移動さぜることを特徴とするリアフォーカス型レン
ズにある。This problem is also the same in a zoom lens that includes a moving lens group for zooming stops.In the present invention, a lens with a rear focus type lens having a moving lens group for 7 focusing stops on the image side, and an exit pupil. This was done to ensure that the position does not change even when focusing. To achieve this purpose, the gist of the present invention is to provide an aperture on the object side of the lens group for focusing, and to use this aperture so that the exit pupil position during focusing is always at a constant position. This is a rear focus type lens that is characterized by a fixed movement.
以下本発明を図面に示す実施例に基づいて説明する０
第１図は本発明の一実施例をなすリアフォーカス型のズ
ームレンズの構成概要を示しておυ、物体側よシ順に、
ズーミング時に固定の′第１正レンズ群Ｌ１、ズーミン
グのだめの第２負レンズ群Ｌ２、絞シＳ１ズーミングの
だめの第３正レンズ群Ｌ３を配し、て構成されている。The present invention will be described below based on an embodiment shown in the drawings. Figure 1 shows an outline of the configuration of a rear focus type zoom lens that is an embodiment of the present invention.
It is constructed by disposing a first positive lens group L1 that is fixed during zooming, a second negative lens group L2 that is a stop for zooming, and a third positive lens group L3 that is a stop for zooming.
なお図中下半部はズーミング時における各レンズ群Ｌｘ
−Ｌｓおよび絞Ｊ）Ｓの光軸上での動きの関係を示して
いる。The lower half of the figure shows each lens group Lx during zooming.
-Ls and the movement of the aperture J)S on the optical axis.
そして前記構成において、絞りＳがズーミングのために
移動する構成となっているのは、本発明と直接関係ない
がズーミング時において射出瞳を一定位置に保つためで
ある。In the above configuration, the reason why the diaphragm S moves for zooming is to keep the exit pupil at a constant position during zooming, although this is not directly related to the present invention.
このような構成をなすレンズ系の、数値例を下記表１に
よシ示す。A numerical example of a lens system having such a configuration is shown in Table 1 below.
表 ま
たたし表中において ｆ：全系の焦点距離ｆ１〜ｆ３：
各レンズ群の焦点距離
ｅ１〜ｅ３：各レンズ群および絞シ間の間隔
ｓ′に二バックフォーカス
１／ ：レンズ群Ｌ３からの射出瞳距離
添字Ｗｔ、Ｔはレンズ群の配置が広角端、望遠端にある
ことを示している
さてこのような構成のズームレンズにおいて、本実施例
では絞シＳ、！ニジ像側の第３レンズ群Ｌ３が、フォー
カシングのだめの移動レンズ群として兼用されておｐ１
７オーカシング時にこのレンズ群Ｌ３は光軸上を移動す
る、したがって前記表１に示したズーミング時の絞Ｄｓ
の移動を行なっても、これとは別に第３レンズ群Ｌ３を
フォーカシングのために移動させると、射出瞳位置はそ
のままでは変化してしまう。In the table, f: Focal length of the entire system f1 to f3:
Focal length e1 to e3 of each lens group: The distance s' between each lens group and diaphragm is 2 Back focus 1/: Exit pupil distance from lens group L3 Subscripts Wt and T indicate that the arrangement of the lens groups is at the wide-angle end or telephoto. In a zoom lens with such a configuration, in this example, the aperture is S,! The third lens group L3 on the rainbow image side is also used as a moving lens group for focusing.
7. During focusing, this lens group L3 moves on the optical axis. Therefore, the diaphragm Ds during zooming shown in Table 1 above
Even if this movement is performed, if the third lens group L3 is moved separately for focusing, the exit pupil position will change as it is.
そこで前記絞υＳをフォーカシング時において第３レン
ズ群Ｌ３に連係して移動させ、射出瞳位置をフォーカシ
ング時にも常に一定位置に保つようにしたことに本発明
の特徴がある。Therefore, the present invention is characterized in that the aperture υS is moved in conjunction with the third lens group L3 during focusing, and the exit pupil position is always maintained at a constant position even during focusing.
例えば前記実施例において、広角端の配置状況で、第３
レンズ群Ｌ３と絞Ｂｓをフォーカシングのために０．３
２９ｇｍ物体側に移動させると、５１＝−１５８８，５
７朋となシ、１／ ＝＝＝−ωとなりて射出瞳位置を変
化させないようにできる。For example, in the above embodiment, in the arrangement situation at the wide-angle end, the third
Lens group L3 and aperture Bs are set to 0.3 for focusing.
When moving 29gm to the object side, 51=-1588,5
7, 1/===-ω, and the exit pupil position can be prevented from changing.
なおＩ！１１は第ルンズ群Ｌｌ （又は第２図のＬ４
）から測った被写体までの距離である。In addition, I! 11 is the lunz group Ll (or L4 in Fig. 2)
) is the distance to the subject measured from
また望遠端の配置状況で、第３レンズ群Ｌ３と絞シＳを
フォーカシングのために４龍物体側に移動させると、ｓ
１＝ １５８８．５７ｍｍＮｔ／に＝ ”となって射
出瞳位置を没化させないようにできる。Also, when the third lens group L3 and diaphragm S are moved to the object side for focusing at the telephoto end, s
1=1588.57 mmNt/='', and the exit pupil position can be prevented from disappearing.
このように絞シよシ像側のレンズ群をフォーカシングの
ために移動させることと連係して絞シを移動させること
によシ、７オ一カシング時の射出瞳位置を常に一定に保
つことができ、全体の小型化等の目的のために採用され
るリアフォーカス型レンズ（前記実施例ではズームレン
ズ）を、色分解光学系を不するカラーカメラに使用する
場合の問題点は効果的に解消されることになる。In this way, by moving the diaphragm in conjunction with moving the lens group on the image side for focusing, it is possible to keep the exit pupil position constant at all times during focusing. This effectively solves the problem when using a rear focus lens (zoom lens in the above embodiment), which is adopted for the purpose of overall miniaturization, in a color camera that does not have a color separation optical system. will be done.
なお前記した絞シの７オ一カシング時における移動、ま
た前記実施例のようなズーミング時の絞シの移動はカム
手段等によって実現できる。また絞シの移動に伴なう口
径比の変化を防止する上から、適当な絞υ開度調節機構
を設けることが実用上望ましい。The movement of the diaphragm during 7-focusing as described above and the movement of the diaphragm during zooming as in the above embodiment can be realized by a cam means or the like. Furthermore, in order to prevent changes in the aperture ratio due to movement of the diaphragm, it is practically desirable to provide an appropriate diaphragm υ opening adjustment mechanism.
第２図は本発明を望遠タイプの固定焦点距離レンズに適
用し５た場合の実施例を示し、図示の如く物体側の正レ
ンズ群Ｌ４と、像側の負レンズ群Ｌ６の間に絞シＳが配
設されている。これらの配置関係の一数値例を下記表２
に示す。FIG. 2 shows an embodiment in which the present invention is applied to a telephoto type fixed focal length lens. S is arranged. Table 2 below shows a numerical example of these placement relationships.
Shown below.
表 ２
なお、全系の焦点距離はｆ＝２００、’マツクツオーカ
スはＳ′に＝１００、負レンズ群Ｌ５からの射出瞳距離
はｔ′、ｃ＝−２３，０７６９２（像面から−１２３，
０７６９２）である。Table 2 The focal length of the entire system is f = 200, 'Matsukutsu focus S' = 100, exit pupil distance from negative lens group L5 is t', c = -23,07692 (-123,
07692).
ここでフォーカシングのために負レンズ群Ｌ５を単独に
像側に例えば１０間移動させると、８１＝−１４５７，
１４關、ｔ′よ＝−２８，５７１４２（像面より−１１
８，５７１４３）となるが、これに連係して絞シＳを９
．４２５２８ｍｍ物体側に移動させることによシｔ’−
−３３，０７６９２’（像面より −１２３，０７’６
９２ｍｖｉ ）一
とすることができる。Here, if the negative lens group L5 is individually moved toward the image side for example by 10 distances for focusing, 81=-1457,
14 degrees, t' = -28,57142 (-11 from the image plane
8,57143), but in conjunction with this, the diaphragm S is 9
．． By moving 42,528 mm to the object side, t'-
-33,07692' (from the image plane -123,07'6
92 mvi).
種々のフォーカシング時の負レンズ群Ｌ５の移動に連係
した絞ムＳの射出瞳位置を一定位置に保つ移動量は、カ
ム手段等によって与えればよい。The amount of movement for keeping the exit pupil position of the diaphragm S at a constant position in conjunction with the movement of the negative lens group L5 during various focusing operations may be provided by a cam means or the like.
なお本発明は前記実施例に宗したもの以外のレンズタイ
プやズームレンズ、例えば固定焦点距離レンズにおいて
は望遠タイプのみならず広角に適したレトロフォーカス
タイプや標準レンズに用いられる種々のレンズタイプ、
ズームレンズにおいては例に示した３群構成のものに限
定されずよシ多くの群から構成されるもの例えば４群以
上の構成のものや逆に２群構成のもの、さらに移動する
レンズ群のレンズ全系に占める位置やその群数にかかわ
らず、すべてのズームレンズについて同様に適用可能で
ある。Note that the present invention is applicable to lens types and zoom lenses other than those based on the above-described embodiments, such as not only telephoto types in fixed focal length lenses, but also retrofocus types suitable for wide angle lenses, various lens types used in standard lenses,
Zoom lenses are not limited to those with a three-group structure as shown in the example, but also those with many groups, such as those with four or more groups, conversely, those with a two-group structure, and even those with a moving lens group. The present invention can be similarly applied to all zoom lenses, regardless of the position occupied in the entire lens system or the number of groups.
以上説明し／・−ように、本発明によれは絞シより像側
のレンズをフォーカシングに用いるいわゆるリアーフォ
ーカスタイプのシングルレンズやズームレンズをカラー
カメラに適用しても、色再現性を良好に保つことが可能
であシ、リアーフォーカスによる小型化を性能の劣下な
く有効に実現できるためその重用性は極めて大なるもの
である。As explained above, the present invention provides good color reproducibility even when a so-called rear focus type single lens or zoom lens, in which the lens on the image side of the aperture is used for focusing, is applied to a color camera. It is extremely useful because it can be maintained in a fixed position, and miniaturization by rear focusing can be effectively realized without deterioration in performance.
図面は本発明の実施例を示すものであシ、第１図はズー
ムレンズに適用した場合の構成概要図、第２図は固定焦
点・距離レンズに適用した場合の構成概要図を示してい
る。
７−′ｌ
岸 １） 正 行 閣
′−７り
新 部 興 治 ： 。
□・旨、−」
第１図
第２図The drawings show embodiments of the present invention; FIG. 1 shows a schematic diagram of the configuration when applied to a zoom lens, and FIG. 2 shows a schematic diagram of the configuration when applied to a fixed focal length/distance lens. . 7-'l Kishi 1) Masayuki Kaku'-7 Rishinbe Koji:. □・To the effect, -” Figure 1 Figure 2
Claims (1)
設し、との絞シをフォーカシング時の射出瞳位置が常に
一定位置にあるよう移動させることを特徴とするリアフ
ォーカス型レンズ。A rear focus type lens characterized in that an aperture is disposed on the object side of the focusing lens group, and the aperture is moved so that the exit pupil position during focusing is always at a constant position.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP58033442A JPS59159118A (en) | 1983-03-01 | 1983-03-01 | Rear focus type lens |
| US06/582,457 US4708444A (en) | 1983-03-01 | 1984-02-22 | Photographic objective |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP58033442A JPS59159118A (en) | 1983-03-01 | 1983-03-01 | Rear focus type lens |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS59159118A true JPS59159118A (en) | 1984-09-08 |
Family
ID=12386642
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP58033442A Pending JPS59159118A (en) | 1983-03-01 | 1983-03-01 | Rear focus type lens |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS59159118A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6167815A (en) * | 1984-09-12 | 1986-04-08 | Kino Seimitsu Kogyo Kk | Macrolens |
| JPS61138912A (en) * | 1984-12-11 | 1986-06-26 | Asahi Optical Co Ltd | Focusing system of telephoto macro-lens |
| JPH04106512A (en) * | 1990-08-27 | 1992-04-08 | Canon Inc | Rear focus system variable power lens |
-
1983
- 1983-03-01 JP JP58033442A patent/JPS59159118A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6167815A (en) * | 1984-09-12 | 1986-04-08 | Kino Seimitsu Kogyo Kk | Macrolens |
| JPS61138912A (en) * | 1984-12-11 | 1986-06-26 | Asahi Optical Co Ltd | Focusing system of telephoto macro-lens |
| JPS6331764B2 (en) * | 1984-12-11 | 1988-06-27 | Asahi Optical Co Ltd | |
| JPH04106512A (en) * | 1990-08-27 | 1992-04-08 | Canon Inc | Rear focus system variable power lens |
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