JPH0532807Y2 - - Google Patents
Info
- Publication number
- JPH0532807Y2 JPH0532807Y2 JP1986170937U JP17093786U JPH0532807Y2 JP H0532807 Y2 JPH0532807 Y2 JP H0532807Y2 JP 1986170937 U JP1986170937 U JP 1986170937U JP 17093786 U JP17093786 U JP 17093786U JP H0532807 Y2 JPH0532807 Y2 JP H0532807Y2
- Authority
- JP
- Japan
- Prior art keywords
- lens group
- lens
- focusing
- zoom
- groups
- 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.)
- Expired - Lifetime
Links
- 150000001875 compounds Chemical class 0.000 claims description 18
- 230000008859 change Effects 0.000 claims description 6
- 230000003287 optical effect Effects 0.000 claims description 6
- 238000000034 method Methods 0.000 description 14
- 230000004075 alteration Effects 0.000 description 8
- 238000003384 imaging method Methods 0.000 description 7
- 238000010586 diagram Methods 0.000 description 5
- 230000000694 effects Effects 0.000 description 5
- 239000002131 composite material Substances 0.000 description 3
- 230000007246 mechanism Effects 0.000 description 3
- 230000009471 action Effects 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 230000004044 response Effects 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
- G02B15/16—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 with interdependent non-linearly related movements between one lens or lens group, and another lens or lens group
- G02B15/163—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 with interdependent non-linearly related movements between one lens or lens group, and another lens or lens group having a first movable lens or lens group and a second movable lens or lens group, both in front of a fixed lens or lens group
- G02B15/167—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 with interdependent non-linearly related movements between one lens or lens group, and another lens or lens group having a first movable lens or lens group and a second movable lens or lens group, both in front of a fixed lens or lens group having an additional fixed front lens or group of lenses
- G02B15/173—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 with interdependent non-linearly related movements between one lens or lens group, and another lens or lens group having a first movable lens or lens group and a second movable lens or lens group, both in front of a fixed lens or lens group having an additional fixed front lens or group of lenses arranged +-+
-
- 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
- G02B15/145—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 five groups only
- G02B15/1451—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 five groups only the first group being positive
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Nonlinear Science (AREA)
- Lenses (AREA)
Description
本考案はズームレンズに関し、特に変倍用レン
ズ群と一体的に移動するレンズ群のうちの一部の
レンズ群を移動させてフオーカシングを行うズー
ムレンズに関するものである。
従来よりズームレンズのフオーカシング方法と
しては、前玉レンズ群を繰出して行ういわゆる前
玉繰出し方法が一般的に良く知られている。
例えば、物体側より順にフオーカス操作時には
移動するが、ズーミング中は固定の第１レンズ
群、変倍作用を行うために可動する第２レンズ
群、像点を一定位置に保持する為に可動する第３
レンズ群、ズーミング中固定である結像系をなす
第４レンズ群より成るいわゆる４成分機械補正式
ズームレンズでは、無限遠物点から近距離物点へ
フオーカシングするときは、前記第１レンズ群を
前後させて行つている。この場合、ある特定の近
距離物点に対しては前記第１レンズ群の物点、像
点の関係が、ズーム操作に無関係であるため、第
１レンズ群の繰出し量はどのようなズーム位置で
あつても一定である。これらが前玉繰出し方式の
フオーカシング方法の最も重要な利点である。し
かしながら次の様な欠点も有する。
高変倍率で、しかも望遠側の焦点距離が比較的
大である様ないわゆる望遠ズームレンズにおいて
は、収差補正上レンズ全長が長くなり、レンズの
前玉径も大きくなる傾向がある。しかもフオーカ
シングによる収差変動を極力少なくするためにフ
オーカシングレンズ群のレンズ構成が複雑とな
る。この為に該レンズ群の重量は格段に重くなる
傾向となる。この様なズームレンズにおいては前
玉繰出しのフオーカシングを行う場合、非常に大
きな駆動力を必要とし、さらにフオーカシング操
作をなめらかに行う為には、それらを満足すべき
精度と耐久性のある鏡筒構造が必要となつてく
る。
従来からこの欠点を改良する手段として、フオ
ーカシングレンズ群である第１レンズ群を複数の
レンズ群に分割し、そのうちの一部のレンズ群で
フオーカシングを行う方法が種々考案されてい
る。この方法により、繰出し量やフオーカシング
レンズ群中の可動レンズ群のレンズ重量を軽減し
てやることは比較的容易である。しかしながら例
えば自動焦点調節用のカメラのレンズとして用い
る場合、さらに次の様な欠点を有する。
自動焦点調節のために、電気信号の制御下にあ
る駆動力、例えばカメラ内部にあるモータ等によ
り、フオーカシングを行う場合、前玉繰出し方法
の様に駆動されるレンズ群が、像側、すなわちカ
メラ内部の駆動力源から最も隔たつた位置にある
と、駆動力を伝達する構造が複雑となる。従つて
自動焦点調節カメラ用のレンズ系としては、
(イ) フオーカシングレンズ群の重量が軽いこと。
(ロ) フオーカシングレンズ群は像面側に近いこ
と。
であることが望ましい。
前玉繰出し方法以外のフオーカシング方法で、
上記の条件を満足してやるために、例えば前述し
た４成分機械補正式ズームレンズの結像系レンズ
群又はその一部を移動させて、無限遠物点から近
距離物点へ、フオーカシングする方法では、フオ
ーカス用のレンズ群の繰出し量がズーム位置によ
つて変化するという問題がある。一般には繰出し
量は、広角側で少なく、望遠側で多く、その量は
ほぼズーム比の２乗に比例する。
このように焦点距離によつてフオーカシングレ
ンズ群の繰出し量が異なるズームレンズである
と、例えば自動焦点調節カメラ用のレンズとして
用いた場合には、繰出し量の大きい望遠側で、精
度良く、かつ迅速な合焦操作を行うべく、駆動さ
せる必要があり、繰出し量の少ない広角側では、
レンズ群駆動速度を、ゆつくりする必要がある。
このようにズーム位置によつてフオーカス用レ
ンズ群の移動量が異つているのは、機構的に複雑
となり好ましくない。
そこで、広角側と望遠側でのフオーカス用レン
ズ群の繰出し量の差を少しでも緩和させるため
に、フオーカシングレンズ群をズーミングに際し
て移動可能としてやることが考えられる。その手
段は大別して
(i) ズーミング中にフオーカシングレンズ群を可
動として、フオーカシングレンズ群の相対的な
位置の変化により、フオーカシングレンズ群の
結像倍率を換え、広角側と望遠側の繰出し量の
差を緩和させる。
(ii) フオーカシングレンズ群の複数のレンズ群で
構成し、それらのレンズ群は、ズーミングに際
して別々に可動とし、フオーカシングレンズ群
自体が屈折力を変えることによつて、広角側と
望遠側の繰出し量の差を緩和させる。（特開昭
56−165107）
がある。
しかしながら、両者ともズーミング中にフオー
カシングレンズ群が移動するために、当然ながら
フオーカシングレンズ群が固定であつた場合と
は、他の移動レンズ群のズーム軌跡が変化し、像
点を一定位置に補正するためのレンズ群の軌跡の
解が存在しなくなつたり、所望のズーム比を得る
ために、変倍レンズ群の屈折力をさらに強めざる
を得ない場合が往往にしておきてくる。
一般に、広角側と望遠側のズーム位置でのフオ
ーカスレンズ群の繰出し量の差を緩和させるため
にフオーカシングレンズ群をズーム操作に応じて
駆動してやると、フオーカシング群の移動による
逆変倍の効果が大きく、高変倍率を達成する上で
は好ましくない。
本考案は、フオーカス用レンズ群の移動による
逆変倍の効果の少ない例えば、自動焦点調節用の
カメラに適したフオーカシング方法を探つたズー
ムレンズの提供を目的とするものである。
そしてこの目的を達成するため、像点位置を一
定に保ちつつ全系の焦点距離を変化させるために
光軸上移動する少なくとも２つのレンズ群を有す
るズームレンズにおいて、前記レンズ群のいずれ
か一方若しくは両方の後方にズーミング操作と連
動させて一体的に移動する複数個のレンズ群より
なる複合レンズ群Ｆを配置し前記複合レンズ群Ｆ
の一部のレンズ群を移動させてフオーカシングを
行うものである。
本考案に係るズームレンズではフオーカス用の
複合レンズ群Ｆの合成屈折力を小さくしている為
に、ズーム操作と共に複合レンズ群Ｆを移動させ
ても、逆変倍の効果がほとんどなく、又収差の発
生も非常に少なく出来る。そしてフオーカスに際
しては複合レンズ群Ｆのうちのある程度の屈折力
を有する一部のレンズ群を移動させて行うので少
ない移動量でフオーカスが行える長所がある。
又比較的、像面側に近いレンズ群を移動させて
いるのでカメラ本体側から駆動させる機構が簡単
になり自動焦点調節を有したカメラに適用するの
に好ましい。
更に複合レンズ群Ｆの一部のレンズ群でフオー
カシングを行う為に、フオーカス用の可動レンズ
群の相対的な位置が変化し、結像倍率の差を利用
して、広角側と望遠側の繰出し量の差を緩和させ
ることが可能となる。またこの場合、広角側で
は、複合レンズ群Ｆのうちの屈折力の小なるレン
ズ群でフオーカシングを行い、望遠側では、複合
レンズ群Ｆのうち屈折力の大なるレンズ群でフオ
ーカシングを行い、広角側と望遠側の繰出し量の
差を緩和させることもできる。
以上のレンズ構成によつて本考案の目的は達成
されるが、具体的には次の条件を満足するのが好
ましい。
合成屈折力の小さい複合レンズ群Ｆの焦点距離
をfF、望遠端のズーム位置における全系の焦点距
離をfTとするとき
(1) −１／3fT＜１／fF＜１／3fT
なる条件を満足くする。
このような範囲内に焦点距離を設定することに
より複合レンズ群Ｆをズーム操作と共に移動させ
ても逆変倍の効果は少なく、かつ収差発生量を少
なくすることが出来る。
条件式(1)の上限値若しくは下限値を越えると逆
変倍の効果が出て来てズームレンズの高変倍化に
好ましくなく、又収差発生量が多くなり良好なる
光学性能を得るのが困難となる。
更に本考案に係る複合レンズ群Ｆを正と負の屈
折力を有する２つのレンズ群で構成し、フオーカ
シングは、そのうち一方のレンズ群を移動させて
行うのが好ましい。
合成屈折力をなるべく小さくし、かつフオーカ
シングにおいてはある程度の屈折力を有するレン
ズ群を移動させて行う必要があるので、複合レン
ズ群Ｆを正と負の屈折力を有する２つのレンズ群
で構成すればレンズ構成が簡単となり、又レンズ
群の移動機構も簡単となる。
更に本考案においては、複合レンズ群Ｆのうち
から任意の複数のレンズ群を一体的若しくは独立
的に移動させてフオーカスをする方法も可能であ
る。
このような方法は収差発生を極力押えてフオー
カシングが出来るのでズームレンズの高性能化を
図るには好ましい。
次に本考案に係るズームレンズの実施例を各図
と共に説明する。
第１図と第２図は各々本考案の実施例１、実施
例２のズームレンズのフオーカス方法を示す光学
系の説明図である。
第１図において、Ｖは変倍用のレンズ群、Ｃは
像面補正用のレンズ群、Ｆは複合レンズ群で正の
屈折力のレンズ群F1と負の屈折力のレンズ群F2
を有している。ズーム操作と共に複合レンズ群Ｆ
を移動させ、フオーカシングのときはレンズ群
F1若しくはレンズ群F2のみを移動させる。Ｐは
レンズ群Ｖの前方に配置したレンズ群、Ｒは結像
用レンズ群であり、レンズ群Ｐとレンズ群Ｒはな
くてもよい。
第２図において、V1とV2は各々変倍用のレン
ズ群、その他のレンズ群は第１図と同様である。
第３図は、像面補正用のレンズ群の機能を２つ
のレンズ群C1とC2に負担させた例で、結像用レ
ンズ群は存在しない。又、第４図は、変倍用レン
ズ群Ｒと像面補正用レンズ群Ｃの間にフオーカシ
ングのための複合レンズ群Ｆを配置しており、そ
の他のレンズ群は第１図と同様である。尚、変倍
用レンズ群あるいは像面補正用レンズ群の変倍、
補正作用は厳密に区別されるわけではなく、一般
に使われている様に主導的作用を指す。
フオーカシングは第１図と同様にレンズ群F1
若しくはレンズ群F2を移動させて行う。実施例
１、実施例２では複合レンズ群Ｆを２つのレンズ
群で構成した場合を示したが２つ以上のレンズ群
で構成しても良いことは言うまでもない。
次に本考案の実施例１と実施例２のフオーカス
方法を用いたズームレンズの数値実施例を示す。
数値実施例においてRiは物体側より順に第ｉ番
目のレンズ面の曲率半径、Diは物体側より順に
第ｉ番目のレンズ厚及び空気間隔、Niとυiは
夫々物体側より順に第ｉ番目のレンズのガラスの
屈折率とアツベ数である。
数値実施例１，２においてR14は絞り面であ
る。
数値実施例１と数値実施例２のレンズ断面図を
各々第３図、第４図に示す。又、本発明の条件式
に対応する１／3fT、１／fFの数値を以下に示す。
The present invention relates to a zoom lens, and more particularly to a zoom lens that performs focusing by moving some of the lens groups that move integrally with the variable power lens group. Conventionally, as a focusing method for a zoom lens, a so-called front lens extension method, which is performed by extending the front lens group, is generally well known. For example, starting from the object side, the first lens group moves during focus operation but is fixed during zooming, the second lens group moves to perform magnification change, and the second lens group moves to maintain the image point at a fixed position. 3
In a so-called four-component mechanically corrected zoom lens consisting of a fourth lens group forming an imaging system that is fixed during zooming, when focusing from an object point at infinity to a near object point, the first lens group is I'm going back and forth. In this case, since the relationship between the object point and image point of the first lens group is unrelated to the zoom operation for a certain short-distance object point, the amount of extension of the first lens group depends on the zoom position. It remains constant even if These are the most important advantages of the front lens focusing method. However, it also has the following drawbacks. In so-called telephoto zoom lenses that have a high magnification ratio and a relatively long focal length on the telephoto side, the overall length of the lens tends to be long to correct aberrations, and the diameter of the front lens of the lens also tends to be large. Moreover, in order to minimize aberration fluctuations due to focusing, the lens configuration of the focusing lens group becomes complicated. For this reason, the weight of the lens group tends to become significantly heavier. In such a zoom lens, when focusing by extending the front lens, a very large driving force is required, and in order to perform the focusing operation smoothly, the lens barrel structure must have the precision and durability to satisfy these needs. becomes necessary. Conventionally, as a means to improve this drawback, various methods have been devised in which the first lens group, which is a focusing lens group, is divided into a plurality of lens groups, and focusing is performed with some of the lens groups. By this method, it is relatively easy to reduce the amount of extension and the lens weight of the movable lens group in the focusing lens group. However, when used as a camera lens for automatic focusing, for example, it has the following drawbacks. When focusing is performed using a driving force controlled by an electrical signal, such as a motor inside the camera, for automatic focusing, the lens group driven as in the front lens extension method is placed on the image side, that is, the camera. If the position is farthest from the internal driving force source, the structure for transmitting the driving force will be complicated. Therefore, as a lens system for an automatic focusing camera, (a) the weight of the focusing lens group is light; (b) The focusing lens group must be close to the image plane. It is desirable that With a focusing method other than the front lens feeding method,
In order to satisfy the above conditions, for example, in the method of moving the imaging system lens group of the four-component mechanically corrected zoom lens described above or a part thereof, and focusing from an object point at infinity to a near object point, There is a problem in that the amount of extension of the focus lens group changes depending on the zoom position. Generally, the amount of extension is small on the wide-angle side and large on the telephoto side, and the amount is approximately proportional to the square of the zoom ratio. A zoom lens in which the amount of extension of the focusing lens group differs depending on the focal length, for example, when used as a lens for an automatic focusing camera, can be used with high accuracy on the telephoto side, where the amount of extension is large. In order to perform quick focusing operations, it is necessary to drive the lens, and on the wide-angle side where the amount of movement is small,
It is necessary to slow down the lens group drive speed. It is not preferable that the amount of movement of the focus lens group differs depending on the zoom position as described above because it complicates the mechanism. Therefore, in order to alleviate the difference in the amount of extension of the focusing lens group between the wide-angle side and the telephoto side, it is conceivable to make the focusing lens group movable during zooming. The methods are roughly divided into (i) The focusing lens group is movable during zooming, and the imaging magnification of the focusing lens group is changed by changing the relative position of the focusing lens group, and the imaging magnification is changed between wide-angle and telephoto. Alleviates the difference in the amount of feed on both sides. (ii) Consisting of multiple focusing lens groups, these lens groups are movable separately during zooming, and by changing the refractive power of the focusing lens group itself, it can be adjusted to wide-angle and telephoto positions. Alleviates the difference in the amount of feed on both sides. (Tokukai Akira
56−165107). However, in both cases, the focusing lens group moves during zooming, so the zoom locus of the other moving lens groups changes, which is different from when the focusing lens group was fixed, and the image point remains constant. There are many cases where there is no solution to the trajectory of the lens group to correct the position, or where the refractive power of the variable magnification lens group must be further strengthened in order to obtain the desired zoom ratio. . In general, if the focusing lens group is driven in response to the zoom operation in order to alleviate the difference in the amount of extension of the focus lens group between the wide-angle and telephoto zoom positions, the reverse magnification change due to the movement of the focusing group This has a large effect and is not preferable in achieving a high magnification ratio. An object of the present invention is to provide a zoom lens that has a focusing method suitable for, for example, an automatic focusing camera, in which the effect of reverse magnification change due to movement of a focusing lens group is small. In order to achieve this objective, in a zoom lens having at least two lens groups that move along the optical axis in order to change the focal length of the entire system while keeping the image point position constant, one of the lens groups or A compound lens group F consisting of a plurality of lens groups that moves integrally in conjunction with the zooming operation is arranged behind both, and the compound lens group F
Focusing is performed by moving some of the lens groups. In the zoom lens according to the present invention, the composite refractive power of the focusing compound lens group F is made small, so even if the compound lens group F is moved with the zoom operation, there is almost no effect of inverse magnification, and there is no aberration. The occurrence of this can also be extremely reduced. Focusing is performed by moving a part of the compound lens group F that has a certain degree of refractive power, so there is an advantage that focusing can be achieved with a small amount of movement. Furthermore, since the lens group relatively close to the image plane side is moved, the mechanism for driving it from the camera body side is simplified, which is preferable for application to cameras with automatic focus adjustment. Furthermore, in order to perform focusing with some lens groups of compound lens group F, the relative position of the movable focusing lens group changes, and by utilizing the difference in imaging magnification, it is possible to move between the wide-angle side and the telephoto side. It becomes possible to alleviate the difference in quantity. In this case, on the wide-angle side, focusing is performed using the lens group with a small refractive power in the compound lens group F, and on the telephoto side, focusing is performed with a lens group with a large refractive power among the compound lens group F, and the wide-angle It is also possible to alleviate the difference in the amount of extension between the side and telephoto side. Although the objective of the present invention is achieved by the lens configuration described above, specifically, it is preferable to satisfy the following conditions. When the focal length of the compound lens group F with small combined refractive power is f F , and the focal length of the entire system at the telephoto end zoom position is f T , (1) −1/3f T <1/f F <1/3f Satisfy the condition T. By setting the focal length within such a range, even if the compound lens group F is moved together with the zoom operation, the effect of reverse magnification change is small, and the amount of aberrations generated can be reduced. If the upper limit or lower limit of conditional expression (1) is exceeded, the effect of inverse magnification will appear, which is not desirable for increasing the magnification of the zoom lens, and the amount of aberrations will increase, making it difficult to obtain good optical performance. It becomes difficult. Further, it is preferable that the compound lens group F according to the present invention is composed of two lens groups having positive and negative refractive powers, and focusing is performed by moving one of the lens groups. Since it is necessary to make the combined refractive power as small as possible and to move a lens group with a certain degree of refractive power during focusing, the compound lens group F should be composed of two lens groups with positive and negative refractive powers. This simplifies the lens configuration and also simplifies the mechanism for moving the lens group. Furthermore, in the present invention, it is also possible to focus by moving any plurality of lens groups from the compound lens group F, either integrally or independently. Such a method is preferable for improving the performance of a zoom lens because it enables focusing while suppressing the occurrence of aberrations as much as possible. Next, embodiments of the zoom lens according to the present invention will be described with reference to each drawing. 1 and 2 are explanatory diagrams of optical systems showing focusing methods of zoom lenses according to embodiments 1 and 2 of the present invention, respectively. In Figure 1, V is a lens group for variable magnification, C is a lens group for image plane correction, and F is a compound lens group, consisting of a lens group F 1 with positive refractive power and a lens group F 2 with negative refractive power.
have. Composite lens group F along with zoom operation
When focusing, move the lens group.
Only F 1 or lens group F 2 is moved. P is a lens group arranged in front of lens group V, R is an imaging lens group, and lens group P and lens group R may be omitted. In FIG. 2, V 1 and V 2 are lens groups for varying magnification, and the other lens groups are the same as in FIG. 1. FIG. 3 shows an example in which the function of the lens group for image plane correction is carried out by two lens groups C 1 and C 2 , and there is no lens group for image formation. In addition, in FIG. 4, a compound lens group F for focusing is arranged between the variable power lens group R and the image plane correction lens group C, and the other lens groups are the same as in FIG. 1. . In addition, when changing the magnification of the lens group for variable magnification or the lens group for image plane correction,
Corrective action is not strictly distinguished, and as commonly used, refers to dominant action. Focusing is done using lens group F 1 as in Figure 1.
Alternatively, this can be done by moving the lens group F2 . In Examples 1 and 2, the case where the composite lens group F is composed of two lens groups is shown, but it goes without saying that it may be composed of two or more lens groups. Next, numerical examples of zoom lenses using the focusing methods of the first and second embodiments of the present invention will be shown.
In the numerical examples, Ri is the radius of curvature of the i-th lens surface from the object side, Di is the thickness and air gap of the i-th lens from the object side, and Ni and υi are the i-th lens surface from the object side, respectively. are the refractive index and Atsube number of the glass. In Numerical Examples 1 and 2, R14 is the aperture surface. Lens sectional views of Numerical Example 1 and Numerical Example 2 are shown in FIGS. 3 and 4, respectively. Further, the numerical values of 1/3f T and 1/f F corresponding to the conditional expression of the present invention are shown below.
【表】【table】
【表】【table】
【表】【table】
【表】【table】
【表】
数値実施例１は、前述の４成分機械補正式ズー
ムレンズの結像系レンズ群（第４群）中に、合成
屈折力が小さい、正、負の屈折力のレンズ群を挿
入した例でありR15からR19より構成される正レ
ンズ群をフオーカシングの為に用いる場合で、近
距離物点（像面より３ｍ）に対する繰出し量は、
広角端で0.46mm、望遠端で2.99mmとなつており、
その比6.5はズーム比の２乗7.5よりも小さく、広
角側と望遠側の繰出し量の差が緩和されている。
数値実施例２は、ズーミングに際し変倍用の正
の屈折力の第１レンズ群V1、負の屈折力の第２
レンズ群V2と像面補正用の、正の屈折力の第３
レンズ群Ｃ、そして第４レンズ群F1と第５レン
ズ群F2が移動可能で、近距離物点に対しては第
４レンズ群でフオーカシングを行う例である。
数値実施例２では、R15からR19よりなり正の
屈折力を有する第４レンズ群を前方に繰出すこと
によりフオーカシングを行う。近距離物点（1.5
ｍ）に対する繰出し量は、広角端で0.96mm、望遠
端で6.26mmとなつており、その比6.5はズーム比
の２乗7.5よりも小さく、広角側と望遠側の繰出
し量の差が縮小されている。
更に数値実施例３と数値実施例４のレンズ断面
図を各々第１１図と第１２図に示す。[Table] In Numerical Example 1, lens groups with positive and negative refracting powers with small combined refractive power are inserted into the imaging system lens group (fourth group) of the four-component mechanically corrected zoom lens described above. As an example, when using a positive lens group consisting of R15 to R19 for focusing, the amount of extension for a short distance object point (3 m from the image plane) is:
It is 0.46mm at the wide-angle end and 2.99mm at the telephoto end.
The ratio of 6.5 is smaller than the square of the zoom ratio of 7.5, and the difference in the amount of extension between the wide-angle side and the telephoto side is alleviated. Numerical Example 2 has a first lens group V 1 with a positive refractive power and a second lens group with a negative refractive power for zooming.
Lens group V 2 and the third lens with positive refractive power for image plane correction.
This is an example in which the lens group C, the fourth lens group F 1 , and the fifth lens group F 2 are movable, and focusing is performed with the fourth lens group for a close object point. In Numerical Example 2, focusing is performed by moving forward a fourth lens group consisting of R15 to R19 and having positive refractive power. Near object point (1.5
m) is 0.96mm at the wide-angle end and 6.26mm at the telephoto end, and the ratio of 6.5 is smaller than the square of the zoom ratio of 7.5, reducing the difference in the amount of extension between the wide-angle end and the telephoto end. ing. Further, cross-sectional views of lenses of Numerical Example 3 and Numerical Example 4 are shown in FIG. 11 and FIG. 12, respectively.
【表】【table】
【表】【table】
【表】【table】
第１図、第２図は各々本考案の実施例１、実施
例２の光学的配置とズーミングによるズーム軌跡
の説明図、第３図、第４図は各々本考案の数値実
施例１、数値実施例２のレンズ断面図、第５図、
第６図は数値実施例１の第７図、第８図は数値実
施例２の無限遠物点と像面より３ｍの近距離物点
に対する諸収差図であり、第９図、第１０図は
各々本考案の実施例３、実施例４の光学的配置と
ズーミングによるズーム軌跡の説明図、第１１
図、第１２図は各々本考案の数値実施例３、数値
実施例４のレンズ断面図、第１３図は数値実施例
３の、第１４図は数値実施例４の無限遠物点と近
距離物点に対する諸収差図である。図中、ａ，
ｂ，ｃは広角端、中間、望遠端でのズーム位置を
示し、Ｍはメリデイオナル像面、Ｓはサジタル像
面を示す。
Figures 1 and 2 are explanatory diagrams of the optical arrangement and zoom locus by zooming in Example 1 and Example 2 of the present invention, respectively. Figures 3 and 4 are numerical values of Example 1 and Figure 4 of the present invention, respectively. A cross-sectional view of the lens of Example 2, FIG.
6 is a diagram showing various aberrations for an object point at infinity and an object point 3 m from the image plane in numerical example 2. are explanatory diagrams of the optical arrangement and zoom trajectory of the third and fourth embodiments of the present invention and the eleventh embodiment, respectively.
Figures 12 and 12 are lens cross-sectional views of numerical embodiment 3 and numerical embodiment 4 of the present invention, respectively. Figure 13 is numerical embodiment 3, and Figure 14 is numerical embodiment 4 of the infinite distance object point and near distance. It is a diagram of various aberrations for an object point. In the figure, a,
b and c indicate the zoom position at the wide-angle end, middle, and telephoto end, M indicates the meridional image plane, and S indicates the sagittal image plane.
Claims (1)
化させるために光軸上移動する少なくとも２つの
レンズ群を有するズームレンズにおいて、前記レ
ンズ群のいずれか一方若しくは両方の後方にズー
ミング操作と連動させて一体的に移動する複数個
のレンズ群よりなる複合レンズ群Ｆを配置し前記
複合レンズ群Ｆの一部のレンズ群を移動させてフ
オーカシングを行うもので、前記複合レンズ群Ｆ
の焦点距離をfF、望遠端のズーム位置における全
系の焦点距離をfTとするとき −１／3fT＜１／fF＜１／3fT なる条件を満足することを特徴とするズームレン
ズ。[Claims for Utility Model Registration] A zoom lens having at least two lens groups that move along the optical axis in order to change the focal length of the entire system while keeping the image point position constant; A compound lens group F consisting of a plurality of lens groups that moves integrally in conjunction with the zooming operation is arranged behind both, and focusing is performed by moving some of the lens groups of the compound lens group F. The compound lens group F
A zoom that satisfies the condition -1/3f T < 1/f F < 1/3f T , where f F is the focal length of F and f T is the focal length of the entire system at the zoom position at the telephoto end. lens.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1986170937U JPH0532807Y2 (en) | 1986-11-06 | 1986-11-06 |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1986170937U JPH0532807Y2 (en) | 1986-11-06 | 1986-11-06 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6276313U JPS6276313U (en) | 1987-05-15 |
| JPH0532807Y2 true JPH0532807Y2 (en) | 1993-08-23 |
Family
ID=31106111
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1986170937U Expired - Lifetime JPH0532807Y2 (en) | 1986-11-06 | 1986-11-06 |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0532807Y2 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4591780B2 (en) * | 2006-02-13 | 2010-12-01 | ソニー株式会社 | Variable focal length lens system and imaging apparatus |
| JP5126663B2 (en) * | 2007-11-02 | 2013-01-23 | 株式会社ニコン | Zoom lens and optical apparatus provided with the zoom lens |
| JP5675575B2 (en) * | 2011-12-15 | 2015-02-25 | オリンパスイメージング株式会社 | Inner focus lens system and image pickup apparatus including the same |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5532037A (en) * | 1978-08-29 | 1980-03-06 | Nippon Kogaku Kk <Nikon> | Zoom lens system for near distance |
-
1986
- 1986-11-06 JP JP1986170937U patent/JPH0532807Y2/ja not_active Expired - Lifetime
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5532037A (en) * | 1978-08-29 | 1980-03-06 | Nippon Kogaku Kk <Nikon> | Zoom lens system for near distance |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6276313U (en) | 1987-05-15 |
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