JPH0146045B2 - - Google Patents
Info
- Publication number
- JPH0146045B2 JPH0146045B2 JP58088196A JP8819683A JPH0146045B2 JP H0146045 B2 JPH0146045 B2 JP H0146045B2 JP 58088196 A JP58088196 A JP 58088196A JP 8819683 A JP8819683 A JP 8819683A JP H0146045 B2 JPH0146045 B2 JP H0146045B2
- Authority
- JP
- Japan
- Prior art keywords
- lens group
- lens
- magnification
- negative
- focal length
- 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
Links
- 239000002131 composite material Substances 0.000 claims 1
- 230000004075 alteration Effects 0.000 description 21
- 238000010586 diagram Methods 0.000 description 5
- 238000000034 method Methods 0.000 description 4
- 230000000694 effects Effects 0.000 description 3
- 230000003287 optical effect Effects 0.000 description 3
- 230000007423 decrease Effects 0.000 description 2
Classifications
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B13/00—Optical objectives specially designed for the purposes specified below
- G02B13/24—Optical objectives specially designed for the purposes specified below for reproducing or copying at short object distances
-
- 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
- G02B15/177—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 negative front lens or group of lenses
-
- 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
- G02B15/1445—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 negative
- G02B15/144511—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 negative arranged -+-+
Description
本発明は低倍領域だけで（被写体と像の立場を
逆にすれば高倍領域だけで）高変倍比を有する有
限距離用ズームレンズに関する。
有限距離用ズームレンズは、被写体面を像面と
の距離が有限で、その距離を一定に保ちながら変
倍できるズームレンズであるが、低倍領域で使用
される代表的なものにフアクシミリ用ズームレン
ズ（被写体と像の立場を逆にすれば引伸し用ズー
ムレンズ）があり、物像間距離が一定で倍率を連
続的に変えることができるため、作業性が非常に
よくなるという利点をもつている。
従来知られているズームレンズには、無限物体
（倍率０）から約1/10倍程度までの倍率範囲を有
するスチールカメラ用ズームレンズと、等倍近辺
の倍率を有するコピー用ズームレンズがあるが、
本発明は、両者の中間的な倍率範囲を有するズー
ムレンズであり、具体的には低倍領域で1/14〜
１／3.5倍程度の倍率範囲を有するところの、変
倍比が４倍と従来にない高変倍比の有限距離用ズ
ームレンズを提供しようとするものである。
前述のようなスチールカメラ用ズームレンズと
コピー用ズームレンズの中間的な倍率範囲を有す
る有限距離用ズームレンズは、今まで変倍比が２
倍にも満たないものばかりしか知られていない
が、本発明では４倍という高変倍比の有限距離用
ズームレンズを実現できたものである。
スチールカメラ用ズームレンズにおいては、変
倍比が４〜５倍というものが既に公知となつてい
るが、写真撮影用であるため歪曲収差が±３〜５
％と大きく、本発明のような有限距離用ズームレ
ンズとしては使用できない。
また、コピー用ズームレンズにおいては、変倍
比が４〜９倍という高変倍比で、かつ歪曲収差も
小さいものがあるが、等倍を基準として、低倍か
ら等倍のレンズ配置と等倍から高倍のレンズ配置
は相対的には全く同じであり、レンズ構成も左右
ほぼ対称であり、歪曲収差を小さくする事は比較
的容易にできるものの、本発明のように低倍領域
で高変倍比を有するレンズ系には使えない。
本発明は、レンズ群の移動に関していえばスチ
ールカメラ用ズームレンズの移動方式に似てい
る。
すなわち、コピー用ズームレンズのように全系
を移動させて変倍するのではなく、鏡枠の中でレ
ンズ群が移動する事によつて変倍する方式であ
る。
しかし、物像間距離が固定されている事、およ
びズームレンズとしては歪曲収差が約±0.5％程
度以下という非常に小さな値を要求される事は、
コピー用ズームレンズに似ている。
本発明の有限距離用ズームレンズは、後述する
ように構成したことにより、スチールカメラ用ズ
ームレンズの変倍方式を採用しながら歪曲収差を
小さく補正し、かつ高変倍比が実現できたもので
ある。
尚、変倍の方法として、ズームレンズの代わり
に、複数個の固定焦点レンズを回転させるターレ
ツト方式も考えられるが、この方式では、得られ
る倍率が離散的である、事及び物像間距離と倍率
の調整が非常に難しいという欠点がある。
以下本発明を詳述すると、被写体側より、負の
焦点距離を有する第１レンズ群と、正の焦点距離
を有する第２レンズ群と、負の焦点距離を有する
第３レンズ群と、正の焦点距離を有する第４レン
ズ群とから構成され、第１、第２、第３、第４レ
ンズ群すべてを機械的に移動させる事によつて変
倍すると共に被写体面と像面とを一定に保つ事が
できる有限距離用ズームレンズにおいて、第１レ
ンズ群は主に被写体面を像面とを一定距離に保つ
機能を有し、第２、第３、第４レンズ群は主に変
倍機能を有し、第１レンズ群は被写体側から正、
負、負、正のレンズで構成され、この第１レンズ
群の最も被写体側の正レンズ（第１レンズ群とい
う）のｄ−lineの屈折率をN1とする時
(1) 1.67＜N1
を満足し、
第２レンズ群は被写体側から負、正、正のレン
ズで構成され、第３レンズ群は互いに強に凹面を
向い合わせた負、負の配置のレンズ群から構成さ
れ、そのうち少なくとも一つの負レンズ群は正、
負あるいは負、正のはり合せレンズから成る２群
３枚あるいは２群４枚構成であつて、この第３レ
ンズ群の被写体側負レンズ群の像側凹面の曲率半
径をΓ〓ａ、像側負レンズ群の被写体側凹面の曲
率半径をΓ〓ｂ、第３レンズ群内のレンズのｄ−
lineの屈折率の平均値を〓とする時
(2) 0.6＜Γ〓ａ＋Γ〓ｂ／2fs＜1.5
(3) 1.67＜〓
を満足し、
第４レンズ群は負、正、正、正、負のレンズで
構成され、第４レンズ群の第１面の曲率半径を
Γ〓1とする時
(4) −2.5＜Γ〓1／fs＜−1.0
を満足し、かつ、
(5) −0.8＜ms／m1s＜−0.35
(6) 1.1＜ms／m12s＜2.0
(7) −1.0＜ms／m123s＜−0.5
(8) 0.5＜X3／X2＜0.9
(9) 0.5＜X3／X4＜0.9
(10) 1.5＜fBS／fS
ただし
fs：低倍率側の全系の焦点距離
ms：低倍率側の横倍率
m1S低倍率側の第１レンズ群の横倍率
m12S：低倍率側の第１、第２レンズ群の合成横倍
率
m123S：低倍率側の第１〜第３レンズ群の合成横
倍率
Xi：第ｉレンズ群の移動量
fBS：低倍率側のバツクフオーカス
の諸条件を満足するよう構成したバツクフ
オーカスの大きい高変倍有限距離用ズーム
レンズ系である。
鏡枠上、第２レンズ群と第４レンズ群を一体に
移動させれば、あるいは第２、第３、第４レンズ
群を比例的に移動させれば構造は簡単になる。た
だし、光学性能的には、収差のバランスの良い位
置に、第１、第２、第３、第４レンズ群を任意に
配置すれば、より収差が良好に補正される事は明
白である。
条件１は第１レンズ群に関するものである。
第１レンズ群の第１レンズを正レンズにした理
由は歪曲収差を補正するためであるが、条件１の
下限を越えると、第１レンズ群の像側の曲率半径
が小さくなるため、特に低倍率側に歪曲収差が中
間画角で最大値を示し、さらに画角が大きくなる
と歪曲収差が小さくなるという、いわゆる「歪曲
収差の戻り量」が大きくなり、本発明で得ようと
するレンズには使えなくなる。
条件２，３は第３レンズ群に関するものであ
る。条件２の上限を越えると、球面収差、像面わ
ん曲をオーバーにする効果が小さくなり、第２、
第４レンズ群のパワーを小さくしなければ収差の
バランンスが取れなくなり、大型化する。逆に条
件２の下限を越えると、球面収差、像面わん曲が
オーバーに補正過剰となり、ズーミングに伴う球
面収差、像面わん曲の変動の増大を招く。また条
件３の下限を越えると、第３レンズ群が４つのレ
ンズ群の中で最もパワーの強いレンズ群であるた
めに、第３レンズ群を構成する各レンズの曲率半
径が小さくなり、高性能は望めない。
条件４は第４レンズ群に関するものであるが、
歪曲収差を補正するのに重要な条件である。条件
４の上限を越えると歪曲収差の補正には有利であ
るが、球面収差の補正が困難となり、逆に下限を
越えると、ズーミングに対する歪曲収差の変動が
大きくなり本発明の目的に反する。
条件５〜７は各レンズ群のパワー配置に関する
ものである。条件５の上限を越えると、第１レン
ズ群のパワーが小さくなり、第１レンズ群の移動
量が大きくなり小型化に反すると共にバツクフオ
ーカスを大きくするのが困難となる。逆に条件５
の下限を越えると、小型化には有利であるが、コ
ンペンセータとしてはパワーが強くなり過ぎてズ
ーミングに対する諸収差の変動が大きくなる。
条件６の上限を越えると、第２レンズ群のパワ
ーが強くなり過ぎて、特に球面収差の変動が大さ
くなり、逆に下限を越えると、変倍効果が小さく
なるため、第２レンズ群の移動量が増大し大型化
する。
条件７は条件２，３とも関連するが、この条件
７の上限を越えると、第２、第４レンズ群で発生
するアンダーな収差を補正できないし、バツクフ
オーカスも小さくなる。逆に条件７の下限を越え
ると、第３レンズ群のパワーが強くなり過ぎて、
特に像面わん曲の変動が大きくなる。
条件８，９は第２、第３、第４レンズ群の移動
に関するものである。これらの条件８，９の上限
を越えると、第２、第３、第４レンズ群内での変
倍効果が小さくなるために、第２〜第４レンズ群
の移動量が増大し、逆に下限を越えると、第３レ
ンズ群の移動量を小くする事には有利であるが、
第２、第３あるいは第３、第４レンズ群間隔の変
化量が増大し、各レンズ群内での収差発生量を小
さくしなければならなくなり、構成枚数の増大を
招く。
条件10は条件というより本発明の光学系の使用
に対する条件である。条件10の下限を越えると、
光学系と像面の間にミラー等の装置を入れる事が
できなくなる。
以下本発明の実施例１〜３を示す。ここで、ｒ
は曲率半径、ｄはレンズ厚もしくは空気間隔、Ｎ
はｄ−lineの屈折率、ｖはアツベ数、Ｆは∝物体
に対する口径比、ｆは全系の焦点距離、ωは主光
線の半画角、ｍは横倍率、Ｌは物像間距離、fBは
バツクフオーカスである。
The present invention relates to a finite-distance zoom lens having a high zoom ratio only in a low-magnification region (or only in a high-magnification region if the positions of the subject and image are reversed). A finite-distance zoom lens is a zoom lens that has a finite distance between the subject plane and the image plane, and can change magnification while keeping that distance constant. A typical zoom lens used in the low-magnification range is a facsimile zoom lens. There is a lens (if the positions of the subject and image are reversed, it becomes a zoom lens for enlarging), and the distance between the object and image is constant and the magnification can be changed continuously, which has the advantage of greatly improving work efficiency. . Conventionally known zoom lenses include zoom lenses for still cameras that have a magnification range from an infinite object (magnification of 0) to approximately 1/10x, and zoom lenses for copying that have a magnification of around 1:1. ,
The present invention is a zoom lens that has a magnification range intermediate between the two, specifically in the low magnification range from 1/14 to 1/14.
The objective is to provide a zoom lens for finite distances that has a magnification range of about 1/3.5 times and has an unprecedentedly high variable power ratio of 4 times. Until now, finite-distance zoom lenses with a magnification range intermediate between still camera zoom lenses and photocopying zoom lenses have a variable magnification ratio of 2.
Although there are only known zoom lenses that are less than 4x, the present invention has been able to realize a finite distance zoom lens with a high variable power ratio of 4x. It is already known that zoom lenses for still cameras have a variable power ratio of 4 to 5 times, but since they are used for photography, the distortion aberration is ±3 to 5 times.
%, and cannot be used as a finite distance zoom lens like the present invention. In addition, some zoom lenses for copying have a high zoom ratio of 4 to 9 times and have small distortion, but with 1x as the standard, the lens arrangement from low to 1x is equivalent. The lens arrangement from magnification to high magnification is relatively the same, and the lens configuration is almost symmetrical left and right, so it is relatively easy to reduce distortion, but unlike the present invention, where there is a high It cannot be used for lens systems with a magnification ratio. Regarding the movement of the lens group, the present invention is similar to the movement method of a zoom lens for a still camera. That is, instead of changing the magnification by moving the entire system like a copying zoom lens, it is a system in which the magnification is changed by moving the lens group within the lens frame. However, the object-to-image distance is fixed, and a zoom lens is required to have a very small distortion value of about ±0.5% or less.
It's similar to a zoom lens for copying. The finite-distance zoom lens of the present invention is constructed as described below, and uses the zoom lens system for still cameras while minimizing distortion and achieving a high zoom ratio. be. As a method of changing magnification, a turret method in which multiple fixed-focus lenses are rotated instead of a zoom lens may also be considered, but with this method, the obtained magnification is discrete and the distance between objects and images is different. The disadvantage is that it is very difficult to adjust the magnification. To explain the present invention in detail below, from the subject side, a first lens group having a negative focal length, a second lens group having a positive focal length, a third lens group having a negative focal length, and a positive focal length. It consists of a fourth lens group having a focal length, and by mechanically moving all of the first, second, third, and fourth lens groups, the magnification is changed and the object plane and image plane are kept constant. In a zoom lens for finite distances, the first lens group mainly has the function of keeping the subject plane at a constant distance from the image plane, and the second, third, and fourth lens groups mainly have the function of changing magnification. The first lens group is positive from the subject side,
Consisting of negative, negative, and positive lenses, when the d-line refractive index of the positive lens closest to the subject (referred to as the first lens group) in this first lens group is N 1 (1) 1.67<N 1 The second lens group is composed of negative, positive, and positive lenses from the subject side, and the third lens group is composed of negative and negative lens groups with strongly concave surfaces facing each other, of which at least One negative lens group is positive,
It has a configuration of three lenses in two groups or four lenses in two groups consisting of negative or negative and positive lenses, and the radius of curvature of the image side concave surface of the subject side negative lens group of this third lens group is Γ〓a, and the image side The radius of curvature of the concave surface on the subject side of the negative lens group is Γ〓b, and d- of the lens in the third lens group
When the average value of the refractive index of the line is (2) 0.6<Γ〓a+Γ〓b/2f s <1.5 (3) 1.67<〓, the fourth lens group is negative, positive, positive, positive, When it is composed of negative lenses and the radius of curvature of the first surface of the fourth lens group is Γ〓 1 , it satisfies (4) −2.5<Γ〓 1 /f s <−1.0, and (5) − 0.8＜m s /m 1 s＜−0.35 (6) 1.1＜m s /m 12 s＜2.0 (7) −1.0＜m s /m 123 s＜−0.5 (8) 0.5＜X 3 /X 2 ＜ 0.9 ( 9 ) 0.5 < _ Lateral magnification m of the first lens group on the low magnification side m 123S : Combined lateral magnification of the first to third lens groups on the low magnification side X i : i-th lens Amount of group movement f BS : This is a high-power variable finite-distance zoom lens system with a large back focus configured to satisfy various conditions for back focus on the low magnification side. The structure can be simplified by moving the second lens group and the fourth lens group together on the lens frame, or by moving the second, third, and fourth lens groups proportionally. However, in terms of optical performance, it is clear that aberrations can be corrected better if the first, second, third, and fourth lens groups are arbitrarily arranged at positions where aberrations are well balanced. Condition 1 relates to the first lens group. The reason why the first lens in the first lens group is made a positive lens is to correct distortion aberration, but if the lower limit of condition 1 is exceeded, the radius of curvature on the image side of the first lens group becomes small, so Distortion aberration on the magnification side shows a maximum value at an intermediate angle of view, and as the angle of view further increases, the distortion aberration decreases; the so-called "return amount of distortion aberration" increases, and the lens to be obtained by the present invention It becomes unusable. Conditions 2 and 3 relate to the third lens group. When the upper limit of condition 2 is exceeded, the effect of overdoing spherical aberration and curvature of field becomes smaller, and the second
Unless the power of the fourth lens group is reduced, the aberrations will not be balanced and the lens will become larger. On the other hand, if the lower limit of Condition 2 is exceeded, spherical aberration and field curvature will be excessively corrected, leading to an increase in fluctuations in spherical aberration and field curvature associated with zooming. If the lower limit of condition 3 is exceeded, the third lens group has the strongest power among the four lens groups, so the radius of curvature of each lens constituting the third lens group becomes small, resulting in high performance. I can't hope for that. Condition 4 concerns the fourth lens group,
This is an important condition for correcting distortion aberration. Exceeding the upper limit of condition 4 is advantageous for correcting distortion, but it becomes difficult to correct spherical aberration, and conversely, exceeding the lower limit increases fluctuations in distortion with respect to zooming, which is contrary to the purpose of the present invention. Conditions 5 to 7 relate to the power arrangement of each lens group. If the upper limit of condition 5 is exceeded, the power of the first lens group becomes small and the amount of movement of the first lens group becomes large, which goes against miniaturization and makes it difficult to increase the back focus. On the contrary, condition 5
If the lower limit of is exceeded, it is advantageous for miniaturization, but the power becomes too strong as a compensator, and fluctuations in various aberrations with respect to zooming become large. If the upper limit of condition 6 is exceeded, the power of the second lens group becomes too strong, and fluctuations in spherical aberration in particular become large.On the other hand, if the lower limit is exceeded, the variable power effect decreases, so the power of the second lens group becomes too strong. The amount of movement increases and the size increases. Condition 7 is related to Conditions 2 and 3, but if the upper limit of Condition 7 is exceeded, it will not be possible to correct the under aberrations occurring in the second and fourth lens groups, and the back focus will also become small. Conversely, if the lower limit of condition 7 is exceeded, the power of the third lens group becomes too strong,
In particular, fluctuations in field curvature become large. Conditions 8 and 9 relate to movement of the second, third, and fourth lens groups. If the upper limits of these conditions 8 and 9 are exceeded, the magnification change effect within the second, third, and fourth lens groups becomes smaller, so the amount of movement of the second to fourth lens groups increases, and conversely, If the lower limit is exceeded, it is advantageous to reduce the amount of movement of the third lens group, but
The amount of change in the interval between the second, third, or third and fourth lens groups increases, and the amount of aberration generated within each lens group must be reduced, leading to an increase in the number of lenses. Condition 10 is not so much a condition as a condition for use of the optical system of the present invention. If the lower limit of condition 10 is exceeded,
It becomes impossible to insert devices such as mirrors between the optical system and the image plane. Examples 1 to 3 of the present invention are shown below. Here, r
is the radius of curvature, d is the lens thickness or air gap, N
is the refractive index of the d-line, v is the Abbe number, F is the aperture ratio to the object, f is the focal length of the entire system, ω is the half angle of view of the chief ray, m is the lateral magnification, L is the object-to-image distance, f B is a back focus.
【表】【table】
【表】【table】
【表】【table】
【表】【table】
【表】【table】
第１、第３、第５図はそれぞれ実施例１，２，
３に対応する低倍率側の時のレンズ系構成図。第
２図ａ，ｂ，ｃ、第４図ａ，ｂ，ｃ、第６図ａ，
ｂ，ｃはそれぞれ実施例１，２，３に対応する諸
収差図で、ａは低倍率側、ｂは中間倍率、ｃは高
倍率側の収差図を示す。
図中でriは各レンズ面の曲率半径、diはレンズ
厚もしくはレンズ面間隔である。
1, 3, and 5 are Examples 1, 2, and 5, respectively.
FIG. 3 is a configuration diagram of the lens system at the low magnification side corresponding to No. 3. Figure 2 a, b, c, Figure 4 a, b, c, Figure 6 a,
b and c are various aberration diagrams corresponding to Examples 1, 2, and 3, respectively, where a shows the aberration diagram on the low magnification side, b shows the aberration diagram on the intermediate magnification side, and c shows the aberration diagram on the high magnification side. In the figure, r i is the radius of curvature of each lens surface, and d i is the lens thickness or distance between lens surfaces.
Claims (1)
ンズ群と、正の焦点距離をする第２レンズ群と、
負の焦点距離を有する第３レンズ群と、正の焦点
距離を有する第４レンズ群とから構成され、第
１、第２、第３、第４レンズ群すべてを機械的に
移動させる事によつて変倍すると共に被写体面と
像面とを一定に保つ事ができる有限距離用ズーム
レンズにおいて、第１レンズ群は主に被写体面と
像面とを一定距離に保つ機能を有し、第２、第
３、第４レンズ群は主に変倍機能を有し、第１レ
ンズ群の最も被写体側のレンズは正レンズ（第１
レンズという）であり、この第１レンズのｄ−
lineの屈折率をN1とする時 (1) 1.67＜N1 を満足し、 第３レンズ群は互いに凹の強い面を向い合わせ
た負、負の配置のレンズ群から構成され、この第
３レンズ群の被写体側負レンズ群の像側凹面の曲
率半径をΓ〓ａ、像側負レンズ群の被写体側凹面
の曲率半径をΓ〓ｂ、第３レンズ群内のレンズの
ｄ−lineの屈折率の平均値を〓とする時 (2) 0.6＜Γ〓ａ＋Γ〓ｂ／2fs＜1.5 (3) 1.67＜〓 を満足し、 第４レンズ群の第１面の曲率半径Γ〓1とする時 (4) −2.5＜Γ〓1／fs＜−1.0 を満足し、かつ、 (5) −0.8＜ms／m1s＜−0.35 (6) 1.1＜ms／m12s＜2.0 (7) −1.0＜ms／m123s＜−0.5 (8) 0.5＜X3／X2＜0.9 (9) 0.5＜X3／X4＜0.9 (10) 1.5＜fBS／fs ただし fs：低倍率側の全系の焦点距離 ms：低倍率側の横倍率 m1S低倍率側の第１レンズ群の横倍率 m12S：低倍率側の第１、第２レンズ群の合成横倍
率 m123S：低倍率側の第１〜第３レンズの合成横倍
率 Xi：第１レンズ群の移動量 fBs：低倍率の諸条件を満足するよう構成した事
を特徴とするバツクフオーカスの大きい高変倍有
限距離用ズームレンズ。 ２ 第２レンズ群と第４レンズ群が一体に移動す
る事を特徴とする特許請求の範囲第１項記載の高
変倍有限距離用ズームレンズ。[Claims] 1. From the subject side, a first lens group having a negative focal length, a second lens group having a positive focal length,
It consists of a third lens group with a negative focal length and a fourth lens group with a positive focal length, and by mechanically moving all of the first, second, third, and fourth lens groups. In a finite-distance zoom lens that can change magnification and maintain a constant distance between the subject plane and the image plane, the first lens group mainly has the function of keeping the subject plane and the image plane at a constant distance, and the second lens group has the function of keeping the subject plane and image plane at a constant distance. , the third and fourth lens groups mainly have a variable magnification function, and the lens closest to the subject in the first lens group is a positive lens (the first
), and the d-
When the refractive index of the line is N 1 , (1) 1.67<N 1 is satisfied, and the third lens group is composed of negative and negative lens groups with strongly concave surfaces facing each other. The radius of curvature of the concave surface on the image side of the negative lens group on the object side of the lens group is Γ〓a, the radius of curvature of the concave surface on the object side of the negative lens group on the image side is Γ〓b, and the refraction of the d-line of the lens in the third lens group is When the average value of the ratio is (2) 0.6<Γ〓a+Γ〓b/2f s <1.5 (3) 1.67<〓, the radius of curvature of the first surface of the fourth lens group is Γ〓 1 (4) −2.5＜Γ〓 1 /f s <−1.0, and (5) −0.8＜m s /m 1 s＜−0.35 (6) 1.1＜m s /m 12 s＜2.0 (7) −1.0＜m s ／m 123 s＜−0.5 (8) 0.5＜X 3 ／X 2 ＜0.9 (9) 0.5＜X 3 ／X 4 ＜0.9 (10) 1.5＜f BS ／ f sHowever f s : Focal length of the entire system on the low magnification side m s : Lateral magnification m on the low magnification side 1S Lateral magnification of the first lens group on the low magnification side m 12S : Combination of the first and second lens groups on the low magnification side Lateral magnification m 123S : Composite lateral magnification of the first to third lenses on the low magnification side X i : Amount of movement of the first lens group f Bs : A back focus system characterized by being configured to satisfy various conditions of low magnification. Large, high variable power zoom lens for finite distances. 2. The high variable power finite distance zoom lens according to claim 1, wherein the second lens group and the fourth lens group move together.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP58088196A JPS59214009A (en) | 1983-05-19 | 1983-05-19 | High variable power zoom lens for definite distance |
| IT48211/84A IT1178378B (en) | 1983-05-19 | 1984-05-17 | HIGH VOICE POWER ZOOM TARGET FOR FINISHED DISTANCES |
| DE19843418639 DE3418639A1 (en) | 1983-05-19 | 1984-05-18 | Varifocal lens for finite distances |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP58088196A JPS59214009A (en) | 1983-05-19 | 1983-05-19 | High variable power zoom lens for definite distance |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS59214009A JPS59214009A (en) | 1984-12-03 |
| JPH0146045B2 true JPH0146045B2 (en) | 1989-10-05 |
Family
ID=13936141
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP58088196A Granted JPS59214009A (en) | 1983-05-19 | 1983-05-19 | High variable power zoom lens for definite distance |
Country Status (3)
| Country | Link |
|---|---|
| JP (1) | JPS59214009A (en) |
| DE (1) | DE3418639A1 (en) |
| IT (1) | IT1178378B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH065636U (en) * | 1991-12-25 | 1994-01-25 | 齋藤遠心機工業株式会社 | Chinese medicine decoction device |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2899005B2 (en) * | 1989-01-30 | 1999-06-02 | キヤノン株式会社 | Zoom lens with built-in focus lens |
| DE4315630C2 (en) * | 1993-05-04 | 1996-01-11 | Zeiss Carl Jena Gmbh | Varifocal lens with finite transmission length |
| DE4344366C2 (en) * | 1993-12-24 | 1997-05-28 | Zeiss Carl Jena Gmbh | Optical system with variable image scale |
| JP4507543B2 (en) * | 2003-09-29 | 2010-07-21 | 株式会社ニコン | Zoom lens |
| JP5457750B2 (en) * | 2009-08-03 | 2014-04-02 | オリンパス株式会社 | Variable magnification optical system and imaging apparatus having the same |
| JP6171344B2 (en) * | 2013-01-08 | 2017-08-02 | リコーイメージング株式会社 | Zoom lens system and electronic imaging apparatus including the same |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5711315A (en) * | 1980-06-24 | 1982-01-21 | Konishiroku Photo Ind Co Ltd | Zoom lens with highly variable magnification preceding negative groups |
-
1983
- 1983-05-19 JP JP58088196A patent/JPS59214009A/en active Granted
-
1984
- 1984-05-17 IT IT48211/84A patent/IT1178378B/en active
- 1984-05-18 DE DE19843418639 patent/DE3418639A1/en active Granted
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH065636U (en) * | 1991-12-25 | 1994-01-25 | 齋藤遠心機工業株式会社 | Chinese medicine decoction device |
Also Published As
| Publication number | Publication date |
|---|---|
| IT1178378B (en) | 1987-09-09 |
| DE3418639C2 (en) | 1987-12-17 |
| JPS59214009A (en) | 1984-12-03 |
| DE3418639A1 (en) | 1984-11-22 |
| IT8448211A0 (en) | 1984-05-17 |
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