JPH1048518A - Variable power optical system - Google Patents

Variable power optical system

Info

Publication number
JPH1048518A
JPH1048518A JP8219482A JP21948296A JPH1048518A JP H1048518 A JPH1048518 A JP H1048518A JP 8219482 A JP8219482 A JP 8219482A JP 21948296 A JP21948296 A JP 21948296A JP H1048518 A JPH1048518 A JP H1048518A
Authority
JP
Japan
Prior art keywords
lens group
lens
end state
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
Application number
JP8219482A
Other languages
Japanese (ja)
Other versions
JP3716418B2 (en
Inventor
Motoyuki Otake
基之 大竹
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Nikon Corp
Original Assignee
Nikon Corp
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Nikon Corp filed Critical Nikon Corp
Priority to JP21948296A priority Critical patent/JP3716418B2/en
Publication of JPH1048518A publication Critical patent/JPH1048518A/en
Application granted granted Critical
Publication of JP3716418B2 publication Critical patent/JP3716418B2/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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
    • G02B15/145—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
    • G02B15/145125—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 arranged +--++

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Lenses (AREA)

Abstract

PROBLEM TO BE SOLVED: To make possible the compatibility of miniaturization with the high variable power by providing positive, negative, negative, positive, positive lens groups in order from the object side, moving the groups by increasing/decreasing the air gaps between lenses at the time of varying the power from the wide angle end to the telescopic end and satisfvirng specified conditions. SOLUTION: This system is provided with, in order from the object side, a positive lens group G1, a negative lens group G2, a negative lens group G3, a positive lens group G4 and a positive lens group G5. At the time of varying the power from the wide angle end to the telescopic end, the respective lens groups are moved to the object side so that an air gap between the lens group G1 and the terms group G2, is increased, an air gap between the lens group G2, and the lens group G3 is decreased and an air gap between the lens group G4 and the lens group G5 is increased. By representing the focal distances of lens groups G1, G2, G3 by f1, f2, f3, respectively, time focal distance at the wide angle end of the whole lens system by fw and the focal distance at the telescopic end by ft, the conditions: -0.5<(f2-f3)/(f2.f3)<1/2> <0.3, 0.8<f1/(fw.ft)<1/2> <1/4 are satisfied.

Description

【発明の詳細な説明】DETAILED DESCRIPTION OF THE INVENTION

【０００１】[0001]

【発明の属する技術分野】本発明は変倍光学系に関し、
特に高変倍化が可能で且つ近距離合焦が可能な変倍光学
系に関する。The present invention relates to a variable power optical system,
In particular, the present invention relates to a variable power optical system capable of achieving high zoom ratio and focusing at a short distance.

【０００２】[0002]

【従来の技術】近年、スチルカメラやビデオカメラなど
に用いられる撮影光学系では、ズームレンズが一般的と
なっている。特に、変倍比が３倍を超える、いわゆる高
変倍ズームレンズを備えたカメラが主流となりつつあ
る。2. Description of the Related Art In recent years, a zoom lens is generally used in a photographing optical system used for a still camera, a video camera, and the like. In particular, cameras equipped with a so-called high zoom ratio zoom lens having a zoom ratio exceeding 3 times are becoming mainstream.

【０００３】この種のカメラでは、３５ｍｍ判で焦点距
離が５０ｍｍ程度の画角を焦点距離範囲に含むズームレ
ンズが一般的に用いられている。特に、高変倍ズームレ
ンズには、変倍に際して３つ以上のレンズ群が移動する
ように構成された、いわゆる多群ズームレンズが主に用
いられている。また、撮影光学系とカメラ本体とが一体
的に構成された一体型カメラでは、携帯性が重視され、
小型化や軽量化が要求される。このため、小型化や軽量
化に適したズームレンズに関する提案が種々なされてい
る。[0003] In this type of camera, a zoom lens having a focal length range including an angle of view having a focal length of about 50 mm in a 35 mm format is generally used. In particular, so-called multi-unit zoom lenses, which are configured so that three or more lens groups move during zooming, are mainly used for high-magnification zoom lenses. In addition, in an integrated camera in which the imaging optical system and the camera body are integrally configured, portability is emphasized,
Miniaturization and weight reduction are required. For this reason, various proposals regarding zoom lenses suitable for miniaturization and weight reduction have been made.

【０００４】[0004]

【発明が解決しようとする課題】しかしながら、従来の
高変倍ズームレンズでは、高変倍化を図る際に、望遠端
状態の焦点距離を長くすると、レンズ全長が大きくなっ
たり、絞り径が大きくなったりする。その結果、レンズ
系の大型化、ひいてはカメラの大型化を招き、携帯性も
悪化してしまう。逆に、高変倍化を図る際に、広角端状
態の焦点距離を短くすると、広角端状態における周辺光
量が cos４乗則により著しく不足する。したがって、口
径食を減らす必要が生じるが、開口絞りから離れた位置
に配置されるレンズ群を通過する軸外光束が光軸から離
れて、結果的にレンズ径の大型化を招いてしまう。この
ように、従来のズームレンズでは、小型化と高変倍化と
の両立を達成することが極めて困難であった。However, in the conventional high-magnification zoom lens, if the focal length in the telephoto end state is increased in order to increase the magnification, the overall length of the lens becomes large or the aperture diameter becomes large. Or become. As a result, the size of the lens system is increased, and the size of the camera is increased, and the portability is also deteriorated. Conversely, if the focal length in the wide-angle end state is shortened in order to achieve a high zoom ratio, the amount of peripheral light in the wide-angle end state becomes significantly insufficient due to the cos 4 power law. Therefore, it is necessary to reduce vignetting, but an off-axis light beam passing through a lens group arranged at a position distant from the aperture stop is separated from the optical axis, resulting in an increase in the lens diameter. As described above, it is extremely difficult for the conventional zoom lens to achieve both miniaturization and high zoom ratio.

【０００５】本発明は、前述の課題に鑑みてなされたも
のであり、小型化と高変倍化との両立が可能な変倍光学
系を提供することを目的とする。SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has as its object to provide a variable power optical system capable of achieving both miniaturization and high magnification.

【０００６】[0006]

【課題を解決するための手段】前記課題を解決するため
に、本発明においては、物体側から順に、正の屈折力を
有する第１レンズ群Ｇ１と、負の屈折力を有する第２レ
ンズ群Ｇ２と、負の屈折力を有する第３レンズ群Ｇ３
と、正の屈折力を有する第４レンズ群Ｇ４と、正の屈折
力を有する第５レンズ群Ｇ５とを備え、広角端状態から
望遠端状態への変倍に際して、前記第１レンズ群Ｇ１と
前記第２レンズ群Ｇ２との間に形成される第１空気間隔
は増大し、前記第２レンズ群Ｇ２と前記第３レンズ群Ｇ
３との間に形成される第２空気間隔は増大し、前記第３
レンズ群Ｇ３と前記第４レンズ群Ｇ４との間に形成され
る第３空気間隔は減少し、前記第４レンズ群Ｇ４と前記
第５レンズ群Ｇ５との間に形成される第４空気間隔は変
化するように、少なくとも前記第１レンズ群Ｇ１および
前記第５レンズ群Ｇ５は物体側へ移動し、前記第１レン
ズ群Ｇ１の焦点距離をｆ１とし、前記第２レンズ群Ｇ２
の焦点距離をｆ２とし、前記第３レンズ群Ｇ３の焦点距
離をｆ３とし、広角端状態におけるレンズ系全体の焦点
距離をｆｗとし、望遠端状態におけるレンズ系全体の焦
点距離をｆｔとしたとき、 −０．５＜（ｆ２−ｆ３）／（ｆ２・ｆ３）1/2 ＜０．３ ０．８＜ｆ１／（ｆｗ・ｆｔ）1/2 ＜１．４ の条件を満足することを特徴とする変倍光学系を提供す
る。According to the present invention, a first lens group G1 having a positive refractive power and a second lens group G1 having a negative refractive power are sequentially arranged from the object side. G2 and a third lens group G3 having negative refractive power
And a fourth lens group G4 having a positive refractive power, and a fifth lens group G5 having a positive refractive power. When changing the magnification from the wide-angle end state to the telephoto end state, the first lens group G1 The first air gap formed between the second lens group G2 and the third lens group G2 increases.
The second air gap formed between the third and the third increases.
The third air gap formed between the lens group G3 and the fourth lens group G4 decreases, and the fourth air gap formed between the fourth lens group G4 and the fifth lens group G5 becomes At least the first lens group G1 and the fifth lens group G5 move toward the object side so that the focal length of the first lens group G1 is f1, and the second lens group G2 is changed.
Where f2 is the focal length of the third lens group G3, f3 is the focal length of the entire lens system in the wide-angle end state, and ft is the focal length of the entire lens system in the telephoto end state. -0.5 <(f2-f3) / (f2 · f3) 1/2 <0.3 0.8 <f1 / (fw · ft) 1/2 <1.4 To provide a variable magnification optical system.

【０００７】本発明の好ましい態様によれば、前記第１
レンズ群Ｇ１と前記第４レンズ群Ｇ４との間に配置され
るレンズ群のうちの１つのレンズ群を光軸に沿って移動
させて、近距離物体への合焦を行う。また、広角端状態
における前記第２レンズ群Ｇ２と前記第３レンズ群Ｇ３
との軸上空気間隔をd23wとし、望遠端状態における前記
第２レンズ群Ｇ２と前記第３レンズ群Ｇ３との軸上空気
間隔をd23tとし、前記第２レンズ群Ｇ２の焦点距離をｆ
２とし、前記第３レンズ群Ｇ３の焦点距離をｆ３とし、
広角端状態におけるレンズ系全体の焦点距離をｆｗと
し、望遠端状態におけるレンズ系全体の焦点距離をｆｔ
としたとき、 0.07＜（d23t−d23w）（fw・ft）1/2 ／（f2・f3）＜0.35 の条件を満足することが好ましい。According to a preferred aspect of the present invention, the first
One of the lens groups disposed between the lens group G1 and the fourth lens group G4 is moved along the optical axis to focus on a short-distance object. Further, the second lens group G2 and the third lens group G3 in the wide-angle end state.
, The axial air distance between the second lens group G2 and the third lens group G3 in the telephoto end state is d23t, and the focal length of the second lens group G2 is f23.
2, the focal length of the third lens group G3 is f3,
The focal length of the entire lens system in the wide-angle end state is fw, and the focal length of the entire lens system in the telephoto end state is ft.
In this case, it is preferable to satisfy the following condition: 0.07 <(d23t−d23w) (fw · ft) 1/2 /(f2·f3)<0.35.

【０００８】[0008]

【発明の実施の形態】従来より、一眼レフレックス式の
カメラに用いられる標準ズームレンズ、すなわち３５ｍ
ｍ判フィルム用で焦点距離が５０ｍｍ程度の画角を焦点
距離範囲に含むズームレンズには、主として正負正正の
４群タイプのズームレンズが用いられている。正負正正
４群タイプのズームレンズでは、広角端状態で第１レン
ズ群と第２レンズ群とが強い負の合成屈折力を有し、第
３レンズ群と第４レンズ群とが強い正の合成屈折力を有
し、全体の屈折力配置がレトロフォーカス型となる。そ
して、望遠端状態で、第１レンズ群と第２レンズ群との
間隔を広げて第１レンズ群による収斂作用を強め、第３
レンズ群と第４レンズ群との間隔を広げて第３レンズ群
と第４レンズ群との合成屈折力を正に弱めて、第２レン
ズ群から第４レンズ群の合成屈折力を正に弱めることに
より、レンズ系全体の屈折力配置を望遠型に近づけてい
る。DESCRIPTION OF THE PREFERRED EMBODIMENTS Conventionally, a standard zoom lens used for a single-lens reflex camera, that is, 35 m, has been used.
As a zoom lens for an m-size film and including a field angle of about 50 mm in the focal length range, a four-group type positive / negative / positive / positive zoom lens is mainly used. In the positive / negative / positive / positive four-group type zoom lens, the first lens group and the second lens group have strong negative combined refractive power in the wide-angle end state, and the third lens group and the fourth lens group have strong positive refractive power. It has a synthetic refractive power, and the entire refractive power arrangement becomes a retrofocus type. Then, in the telephoto end state, the distance between the first lens group and the second lens group is widened to enhance the convergence action of the first lens group, and
The distance between the lens group and the fourth lens group is widened to weaken the combined refractive power of the third lens group and the fourth lens group positively, and the combined refractive power of the second lens group to the fourth lens group is weakened positively. This makes the refractive power arrangement of the entire lens system closer to the telephoto type.

【０００９】上述の構成により、広角端状態では第１レ
ンズ群を通過する軸外光束を光軸に近づけてレンズ径の
小型化を図りながら、望遠端状態ではレンズ全長の短縮
化を図っている。また、正負正正４群タイプのズームレ
ンズでは、正負正の３群タイプのズームレンズの最も像
側の正レンズ群を２つの正レンズ群に分割した構成を有
する。そして、分割された２つの正レンズ群の間に形成
される空気間隔を変化させることにより、変倍を行って
いる。したがって、正負正正４群タイプのズームレンズ
では、正負正の３群タイプのズームレンズよりも、高変
倍化に伴って発生する軸外収差の変動を良好に抑えるこ
とができる。With the above-described configuration, the off-axis light beam passing through the first lens unit is brought closer to the optical axis in the wide-angle end state to reduce the lens diameter, while the telephoto end state reduces the overall length of the lens. . Further, the positive / negative / positive / positive four-group type zoom lens has a configuration in which the most image-side positive lens group of the positive / negative / positive three-group type zoom lens is divided into two positive lens groups. The magnification is changed by changing the air gap formed between the two divided positive lens groups. Therefore, in the positive / negative / positive / positive four-group type zoom lens, the fluctuation of the off-axis aberration which occurs with high zoom ratio can be suppressed more favorably than the positive / negative / positive three-group type zoom lens.

【００１０】ところで、正負正正４群タイプのズームレ
ンズでは、第２レンズ群が唯一の負レンズ群である。し
たがって、ペッツバール和を適切な値にするために、第
２レンズ群は強い負屈折力を有する。また、従来より、
小型化と高変倍化とを達成するためには、ズームレンズ
を構成する各レンズ群の屈折力を強めることが効果的で
あることが知られている。特に、第２レンズ群の屈折力
を強めると、広角端状態において第２レンズ群と第３レ
ンズ群との間隔を狭めることができるため、第１レンズ
群を通過する軸外光束が光軸に近づき、レンズ径の小型
化を図ることができる。したがって、第１レンズ群の屈
折力を正に強めても、レンズ径の大型化を招くことがな
く、結果的に望遠端状態のレンズ全長を短縮化すること
ができる。By the way, in a positive / negative / positive / positive four-group type zoom lens, the second lens group is the only negative lens group. Therefore, the second lens group has a strong negative refractive power in order to set the Petzval sum to an appropriate value. Also, conventionally,
It is known that it is effective to increase the refractive power of each lens group constituting a zoom lens in order to achieve miniaturization and high zoom ratio. In particular, when the refractive power of the second lens group is increased, the distance between the second lens group and the third lens group can be reduced in the wide-angle end state, so that the off-axis light beam passing through the first lens group is shifted to the optical axis. As a result, the lens diameter can be reduced. Therefore, even if the refractive power of the first lens unit is positively increased, the lens diameter does not increase, and as a result, the overall length of the lens in the telephoto end state can be reduced.

【００１１】しかしながら、正負正正４群タイプのズー
ムレンズでは、第３レンズ群あるいは第４レンズ群に隣
接して開口絞りが配置されるのが一般的である。したが
って、広角端状態から望遠端状態へ変倍する際に、第２
レンズ群を通過する軸外光束の入射高があまり変化せ
ず、その入射角だけが変化する。このため、高変倍化に
伴って軸外収差の変動が発生しやすく、高い光学性能を
維持するにはレンズ構成枚数を多くしたり、非球面の導
入が不可欠であった。However, in a positive / negative / positive / positive four-group type zoom lens, an aperture stop is generally arranged adjacent to the third lens group or the fourth lens group. Therefore, when zooming from the wide-angle end state to the telephoto end state, the second
The incident height of the off-axis light beam passing through the lens group does not change much, and only the incident angle changes. For this reason, fluctuations in off-axis aberrations are likely to occur with a high zoom ratio, and in order to maintain high optical performance, it is essential to increase the number of lens components and introduce an aspherical surface.

【００１２】そこで、本発明の変倍光学系では、正負正
正４群タイプのズームレンズにおいて正負正３群タイプ
のズームレンズの最も像側の正レンズ群を２つの正レン
ズ群に分割することによって高変倍化を達成したよう
に、正負正正４群タイプのズームレンズにおける負屈折
力の第２レンズ群を２つの負レンズ群に分割している。
そして、分割した２つの負レンズ群を広角端状態から望
遠端状態への変倍に際して独立に移動させることによ
り、変倍に伴う軸外収差の変動を良好に補正して、高性
能化と高変倍化との両立化を達成している。特に、従来
の正負正正４群タイプのズームレンズでは、第２レンズ
群の変倍を担う割合が非常に大きいのに対して、本発明
の変倍光学系では、分割された２つの負レンズ群で変倍
を担う割合を分担することができるので、各レンズ群の
相互偏心に伴う性能劣化を極力抑えることが可能とな
る。Therefore, in the variable power optical system of the present invention, in the positive / negative / positive / positive four-group type zoom lens, the most image-side positive lens group of the positive / negative / positive three-group type zoom lens is divided into two positive lens groups. As a result, the second lens unit having negative refracting power in the positive / negative / positive / positive four-unit type zoom lens is divided into two negative lens units.
Then, by moving the two divided negative lens groups independently at the time of zooming from the wide-angle end state to the telephoto end state, fluctuations in off-axis aberration due to zooming are corrected well, and high performance and high performance are achieved. Achieved compatibility with zooming. In particular, in the conventional zoom lens of the positive, negative, positive, and positive four-group type, the ratio of changing the magnification of the second lens group is very large, whereas in the zoom optical system of the present invention, the two divided negative lenses are divided. Since the ratio in which magnification is changed by the groups can be shared, it is possible to minimize the performance deterioration due to the mutual eccentricity of each lens group.

【００１３】以上の考察に基づいて、本発明の変倍光学
系は、正負負正正の屈折力配置を有し、以下の５つの条
件〜を満足するように各レンズ群を機能させてい
る。 広角端状態では、第１レンズ群Ｇ１〜第３レンズ群Ｇ
３を近づけてその合成屈折力を強い負屈折力とし、第４
レンズ群Ｇ４と第５レンズ群Ｇ５とを近づけてその合成
屈折力を強い正屈折力とし、第３レンズ群Ｇ３と第４レ
ンズ群Ｇ４とを適切な間隔を隔てて配置する。 広角端状態から望遠端状態への変倍時に、第１レンズ
群Ｇ１と第２レンズ群Ｇ２との間隔を広げるように、少
なくとも第１レンズ群Ｇ１を物体側へ移動させる。Based on the above considerations, the variable power optical system of the present invention has a positive, negative, negative, positive and positive refractive power arrangement, and makes each lens group function so as to satisfy the following five conditions. . In the wide-angle end state, the first lens group G1 to the third lens group G
3 and make the combined refractive power a strong negative refractive power.
The lens group G4 and the fifth lens group G5 are brought closer to each other to make the combined refractive power a strong positive refractive power, and the third lens group G3 and the fourth lens group G4 are arranged at an appropriate interval. At the time of zooming from the wide-angle end state to the telephoto end state, at least the first lens group G1 is moved to the object side so as to increase the distance between the first lens group G1 and the second lens group G2.

【００１４】広角端状態から望遠端状態への変倍時
に、第２レンズ群Ｇ２と第３レンズ群Ｇ３との間隔を広
げ、第４レンズ群Ｇ４と第５レンズ群Ｇ５との間隔を広
げるように、第３レンズ群Ｇ３と第４レンズ群Ｇ４との
間隔を狭める。 第２レンズ群Ｇ２の使用倍率β２が変倍範囲の全体に
亘って−１＜１／β２＜１を満たし、第３レンズ群Ｇ３
の使用倍率β３が変倍範囲の全体に亘って−１＜β３＜
１を満たすように、第２レンズ群Ｇ２の屈折力および第
３レンズ群Ｇ３の屈折力を決定する。 第４レンズ群Ｇ４の物体側か、第４レンズ群Ｇ４中
か、あるいは第５レンズ群Ｇ５中に、開口絞りを配置す
る。At the time of zooming from the wide-angle end state to the telephoto end state, the distance between the second lens group G2 and the third lens group G3 is increased, and the distance between the fourth lens group G4 and the fifth lens group G5 is increased. Then, the distance between the third lens group G3 and the fourth lens group G4 is reduced. The use magnification β2 of the second lens group G2 satisfies −1 <1 / β2 <1 over the entire zoom range, and the third lens group G3
Is less than -1 <β3 <over the entire zoom range.
The refractive power of the second lens group G2 and the refractive power of the third lens group G3 are determined so as to satisfy 1. An aperture stop is arranged on the object side of the fourth lens group G4, in the fourth lens group G4, or in the fifth lens group G5.

【００１５】本発明においては、従来の正負正正４群タ
イプのズームレンズと同様に、広角端状態での屈折力配
置を逆望遠型として第１レンズ群Ｇ１のレンズ径の小型
化を図っており、の条件を満足することが望ましい。
望遠端状態では、第１レンズ群Ｇ１と第２レンズ群Ｇ２
との間隔を広げて第１レンズ群Ｇ１による収斂作用を強
めることによって、レンズ全長の短縮化を図っている。
しかしながら、広角端状態におけるレンズ全長を大きく
すると、第１レンズ群Ｇ１を通過する軸外光束が光軸か
ら離れて、第１レンズ群Ｇ１のレンズ径が大型化する。
このため、広角端状態から望遠端状態への変倍に際して
第１レンズ群Ｇ１を物体側へ移動させており、の条件
が必要となる。In the present invention, similarly to the conventional positive / negative / positive / positive positive / negative four-group type zoom lens, the refractive power arrangement in the wide-angle end state is set to be the reverse telephoto type, and the lens diameter of the first lens group G1 is reduced. Therefore, it is desirable that the above condition is satisfied.
In the telephoto end state, the first lens group G1 and the second lens group G2
The overall length of the lens is reduced by increasing the distance between the first lens group and the convergence effect of the first lens group G1.
However, if the overall length of the lens in the wide-angle end state is increased, the off-axis light beam passing through the first lens group G1 is separated from the optical axis, and the lens diameter of the first lens group G1 increases.
Therefore, the first lens group G1 is moved to the object side when zooming from the wide-angle end state to the telephoto end state, and the following condition is required.

【００１６】次に、屈折力φ１のレンズ群と屈折力φ２
のレンズ群とが軸上空気間隔Ｄだけ隔てて配置されてい
る場合、２つのレンズ群の合成屈折力φは次の式（ａ）
で表される。 φ＝φ１＋φ２−φ１・φ２・Ｄ （ａ） ここで、２つのレンズ群の空気間隔がΔだけ広がった場
合、２つのレンズ群の合成屈折力φ’は次の式（ｂ）で
表される。 φ’＝φ１＋φ２−φ１・φ２・（Ｄ＋Δ） （ｂ）Next, a lens group having a refractive power of φ1 and a lens group having a refractive power of φ2
When the lens groups are arranged at an interval D on the axis, the combined refractive power φ of the two lens groups is given by the following equation (a).
It is represented by φ = φ1 + φ2−φ1 · φ2 · D (a) Here, when the air gap between the two lens groups is widened by Δ, the combined refractive power φ ′ of the two lens groups is expressed by the following equation (b). . φ '= φ1 + φ2-φ1 • φ2 · (D + Δ) (b)

【００１７】したがって、２つのレンズ群の合成屈折力
の変化Δφは、次の式（ｃ）で表される。 Δφ＝φ’−φ＝−φ１・φ２・Δ （ｃ） 式（ｃ）を参照すると、２つのレンズ群の屈折力の符号
が同じである場合、２つのレンズ群の合成屈折力はその
空気間隔を広げると負に強まることがわかる。また、２
つのレンズ群の屈折力の符号が互いに異なる場合、２つ
のレンズ群の合成屈折力はその空気間隔を広げると負に
弱まることがわかる。Accordingly, the change Δφ in the combined refractive power of the two lens groups is expressed by the following equation (c). Δφ = φ′−φ = −φ1φ2Δ (c) Referring to equation (c), if the sign of the refractive power of the two lens groups is the same, the combined refractive power of the two lens groups is the air It can be seen that widening the interval increases negatively. Also, 2
When the signs of the refractive powers of the two lens groups are different from each other, it can be seen that the combined refractive power of the two lens groups weakens negatively when the air gap is widened.

【００１８】本発明においては、広角端状態から望遠端
状態への変倍に際して、第２レンズ群Ｇ２と第３レンズ
群Ｇ３との間隔を広げてその合成屈折力を負に強め、第
４レンズ群Ｇ４と第５レンズ群Ｇ５との間隔を広げてそ
の合成屈折力を正に弱め、第２レンズ群Ｇ２と第３レン
ズ群Ｇ３とにより形成される負部分系と第４レンズ群Ｇ
４と第５レンズ群Ｇ５とにより形成される正部分系との
間隔を狭めることにより、広角端状態よりも望遠端状態
において第２レンズ群Ｇ２〜第５レンズ群Ｇ５の合成屈
折力を負に強めている。したがって、条件が必要とな
る。特に、本発明においては、変倍に際して第２レンズ
群Ｇ２と第３レンズ群Ｇ３とを独立に移動させている
が、第２レンズ群Ｇ２は主として軸外収差の補正を、第
３レンズ群Ｇ３は主として軸上収差の補正をそれぞれ担
っている。In the present invention, at the time of zooming from the wide-angle end state to the telephoto end state, the distance between the second lens group G2 and the third lens group G3 is increased to increase the combined refracting power of the fourth lens group to a negative value. The distance between the group G4 and the fifth lens group G5 is widened to weaken the combined refracting power thereof positively, and the negative subsystem formed by the second lens group G2 and the third lens group G3 and the fourth lens group G
By reducing the distance between the fourth lens unit and the positive subsystem formed by the fifth lens unit G5, the combined refractive power of the second lens unit G2 to the fifth lens unit G5 becomes more negative in the telephoto end state than in the wide angle end state. I am strengthening. Therefore, conditions are required. In particular, in the present invention, the second lens group G2 and the third lens group G3 are moved independently during zooming, but the second lens group G2 mainly corrects off-axis aberrations and the third lens group G3 Are mainly responsible for correcting axial aberrations.

【００１９】また、条件を満足するように第２レンズ
群Ｇ２の屈折力と第３レンズ群Ｇ３の屈折力とを配分す
ると、第２レンズ群Ｇ２を通過する軸外光束は光軸から
離れた位置を通過するようになるので、軸上収差と軸外
収差とを独立に補正することが可能となる。特に、変倍
時に第２レンズ群Ｇ２と第３レンズ群Ｇ３との間隔を変
化させることにより、変倍時に第２レンズ群Ｇ２を通過
する軸外光束の高さを変化させて、変倍に伴う軸外収差
の変動も良好に補正している。逆に、第３レンズ群Ｇ３
は、第２レンズ群Ｇ２よりも像側に配置されているの
で、第２レンズ群Ｇ２よりも開口絞りに近く、第３レン
ズ群Ｇ３を通過する軸外光束は光軸に近い。このため、
第３レンズ群Ｇ３により発生する軸外収差の方が、第２
レンズ群Ｇ２により発生する軸外収差よりも少ない。し
たがって、第２レンズ群Ｇ２において軸上収差の補正を
行うことにより、大口径化を図ることができる。When the refractive power of the second lens group G2 and the refractive power of the third lens group G3 are distributed so as to satisfy the condition, the off-axis light beam passing through the second lens group G2 is separated from the optical axis. Since the light passes through the position, the on-axis aberration and the off-axis aberration can be corrected independently. In particular, by changing the distance between the second lens group G2 and the third lens group G3 at the time of zooming, the height of the off-axis light beam passing through the second lens group G2 at the time of zooming is changed. The accompanying fluctuation of off-axis aberration is also corrected well. Conversely, the third lens group G3
Is closer to the image side than the second lens group G2, is closer to the aperture stop than the second lens group G2, and the off-axis light beam passing through the third lens group G3 is closer to the optical axis. For this reason,
The off-axis aberration generated by the third lens group G3 is the second
It is smaller than the off-axis aberration generated by the lens group G2. Therefore, by correcting the axial aberration in the second lens group G2, it is possible to increase the aperture.

【００２０】ところで、高変倍ズームレンズにおいて変
倍に伴う軸外収差の変動を良好に抑えるためには、広角
端状態から望遠端状態へレンズ位置状態が変化する際
に、軸外光束の通過する高さが変化するレンズ群の数を
増やすことが肝要である。これにより、例えば広角端状
態で発生する軸外収差を補正するためのレンズ群や望遠
端状態で発生する軸外収差を補正するためのレンズ群な
どを規定して、各レンズ群の収差補正上の機能を明確に
することができる。本発明においては、広角端状態から
望遠端状態へのレンズ位置状態の変化に伴って、第２レ
ンズ群Ｇ２を通過する軸外光束が光軸に近づき、第１レ
ンズ群Ｇ１を通過する軸外光束が光軸から離れるよう
に、各レンズ群を機能させて高変倍化を達成している。
そして、第４レンズ群Ｇ４の近傍にあるいは第５レンズ
群Ｇ５の近傍に、開口絞りを配置している。In order to suppress the fluctuation of the off-axis aberration caused by zooming in a high-magnification zoom lens, it is necessary to pass an off-axis light beam when the lens position changes from the wide-angle end state to the telephoto end state. It is important to increase the number of lens groups whose height changes. Accordingly, for example, a lens group for correcting off-axis aberrations generated at the wide-angle end state and a lens group for correcting off-axis aberrations generated at the telephoto end state are defined. Function can be clarified. In the present invention, as the lens position changes from the wide-angle end state to the telephoto end state, an off-axis light beam passing through the second lens group G2 approaches the optical axis, and an off-axis light beam passing through the first lens group G1. Each lens group is made to function so that the light beam is separated from the optical axis, thereby achieving high magnification.
Then, an aperture stop is arranged near the fourth lens group G4 or near the fifth lens group G5.

【００２１】以下、本発明の各条件式について説明す
る。本発明においては、次の条件式（１）および（２）
を満足する。 −０．５＜（ｆ２−ｆ３）／（ｆ２・ｆ３）1/2 ＜０．３ （１） ０．８＜ｆ１／（ｆｗ・ｆｔ）1/2 ＜１．４ （２） ここで、 ｆ１：第１レンズ群Ｇ１の焦点距離 ｆ２：第２レンズ群Ｇ２の焦点距離 ｆ３：第３レンズ群Ｇ３の焦点距離 ｆｗ：広角端状態におけるレンズ系全体の焦点距離 ｆｔ：望遠端状態におけるレンズ系全体の焦点距離Hereinafter, each conditional expression of the present invention will be described. In the present invention, the following conditional expressions (1) and (2)
To be satisfied. -0.5 <(f2-f3) / (f2 · f3) 1/2 <0.3 (1) 0.8 <f1 / (fw · ft) 1/2 <1.4 (2) f1: focal length of the first lens group G1 f2: focal length of the second lens group G2 f3: focal length of the third lens group G3 fw: focal length of the entire lens system in the wide-angle end state ft: lens system in the telephoto end state Overall focal length

【００２２】条件式（１）は、第２レンズ群Ｇ２の焦点
距離ｆ２と第３レンズ群Ｇ３の焦点距離ｆ３とのバラン
スを図るための条件式であり、変倍時に発生する軸上収
差の変動と軸外収差の変動とを良好に補正するための条
件を規定している。条件式（１）の上限値を上回った場
合、第２レンズ群Ｇ２の焦点距離が負に小さくなり、広
角端状態において第２レンズ群Ｇ２を通過する軸外光束
が光軸に近づく。その結果、第２レンズ群Ｇ２により軸
上収差と軸外収差とを独立して補正することが難しくな
り、所定の変倍比を維持しながら高性能化を図ることが
困難となってしまう。逆に、条件式（１）の下限値を下
回った場合、第３レンズ群Ｇ３の焦点距離が負に小さく
なり、第３レンズ群Ｇ３において発生する正の球面収差
を少ないレンズ構成枚数で補正することが困難となり、
所定の光学性能を得ることができなくなってしまう。Conditional expression (1) is a conditional expression for balancing the focal length f2 of the second lens group G2 and the focal length f3 of the third lens group G3. Conditions for favorably correcting the fluctuation and the fluctuation of the off-axis aberration are defined. When the value exceeds the upper limit of conditional expression (1), the focal length of the second lens group G2 becomes negative, and the off-axis light beam passing through the second lens group G2 in the wide-angle end state approaches the optical axis. As a result, it becomes difficult to independently correct the on-axis aberration and the off-axis aberration by the second lens group G2, and it becomes difficult to achieve high performance while maintaining a predetermined zoom ratio. Conversely, if the lower limit of conditional expression (1) is not reached, the focal length of the third lens group G3 becomes negative, and positive spherical aberration generated in the third lens group G3 is corrected with a small number of lens components. It becomes difficult,
Predetermined optical performance cannot be obtained.

【００２３】条件式（２）は、第１レンズ群Ｇ１の焦点
距離ｆ１について適切な範囲を規定しており、レンズ系
の短縮化とレンズ径の小型化とのバランスを図るための
条件式である。条件式（２）の上限値を上回った場合、
第１レンズ群Ｇ１の焦点距離が正に大きくなって収斂作
用が弱まるので、望遠端状態でのレンズ全長が大型化し
てしまう。逆に、条件式（２）の下限値を下回ると、広
角端状態において第１レンズ群Ｇ１を通過する軸外光束
が光軸から離れて、画面周辺部において所定の光量を確
保するにはレンズ径の大型化を招いてしまう。なお、望
遠端状態におけるレンズ全長の短縮化をさらに図るに
は、条件式（２）の上限値を１．２に設定することが望
ましい。Conditional expression (2) defines an appropriate range for the focal length f1 of the first lens group G1, and is a conditional expression for achieving a balance between shortening the lens system and miniaturizing the lens diameter. is there. If the upper limit of conditional expression (2) is exceeded,
Since the focal length of the first lens group G1 becomes positive and the convergence effect is weakened, the overall length of the lens in the telephoto end state increases. Conversely, when the value goes below the lower limit of conditional expression (2), the off-axis light beam passing through the first lens group G1 in the wide-angle end state moves away from the optical axis, and a predetermined amount of light is required to secure a predetermined amount of light at the periphery of the screen. This leads to an increase in diameter. In order to further reduce the total lens length in the telephoto end state, it is desirable to set the upper limit of conditional expression (2) to 1.2.

【００２４】また、本発明においては、前述のように、
広角端状態から望遠端状態への変倍に際して第２レンズ
群Ｇ２と第３レンズ群Ｇ３との間隔が変化する。したが
って、第２レンズ群Ｇ２および第３レンズ群Ｇ３を少な
いレンズ枚数で構成するために、以下の条件式（３）を
満足することが望ましい。 0.07＜（d23t−d23w）（fw・ft）1/2 ／（f2・f3）＜0.35 （３） ここで、 d23w：広角端状態における第２レンズ群Ｇ２と第３レン
ズ群Ｇ３との軸上空気間隔 d23t：望遠端状態における第２レンズ群Ｇ２と第３レン
ズ群Ｇ３との軸上空気間隔In the present invention, as described above,
When zooming from the wide-angle end state to the telephoto end state, the distance between the second lens group G2 and the third lens group G3 changes. Therefore, in order to configure the second lens group G2 and the third lens group G3 with a small number of lenses, it is desirable to satisfy the following conditional expression (3). 0.07 <(d23t−d23w) (fw · ft) 1/2 /(f2·f3)<0.35 (3) where, d23w: on the axis of the second lens group G2 and the third lens group G3 in the wide-angle end state. Air gap d23t: axial air gap between the second lens group G2 and the third lens group G3 in the telephoto end state

【００２５】前述の式（ｃ）を参照するとわかるよう
に、条件式（３）において、Δφ＝（d23t−d23w）／
（f2・f3）は、広角端状態から望遠端状態へレンズ位置
状態が変化する際の第２レンズ群Ｇ２と第３レンズ群Ｇ
３との合成屈折力の変化量を表している。したがって、
条件式（３）は、第２レンズ群Ｇ２と第３レンズ群Ｇ３
との変倍作用を規定する条件式である。本発明では、広
角端状態において第２レンズ群Ｇ２と第３レンズ群Ｇ３
とを接近させることにより、第２レンズ群Ｇ２を通過す
る軸外光束を光軸に近づけさせている。逆に、望遠端状
態において、第２レンズ群Ｇ２と第３レンズ群Ｇ３とを
引き離すことにより、第２レンズ群Ｇ２を通過する軸外
光束を光軸から離している。その結果、広角端状態から
望遠端状態へのレンズ位置状態の変化に伴う軸外収差の
変動を良好に補正している。As can be seen by referring to the above equation (c), in the conditional equation (3), Δφ = (d23t−d23w) /
(F2 · f3) are the second lens group G2 and the third lens group G when the lens position state changes from the wide-angle end state to the telephoto end state.
3 represents the amount of change in the combined refractive power. Therefore,
Conditional expression (3) satisfies the second lens group G2 and the third lens group G3.
Is a conditional expression that defines the zooming action of In the present invention, in the wide-angle end state, the second lens group G2 and the third lens group G3
Are brought closer to each other, whereby the off-axis light beam passing through the second lens group G2 is made closer to the optical axis. Conversely, in the telephoto end state, the off-axis light beam passing through the second lens group G2 is separated from the optical axis by separating the second lens group G2 and the third lens group G3. As a result, the fluctuation of off-axis aberration due to the change of the lens position state from the wide-angle end state to the telephoto end state is favorably corrected.

【００２６】条件式（３）の上限値を上回った場合、望
遠端状態において第２レンズ群Ｇ２を通過する軸外光束
の高さの差が小さくなる。その結果、変倍に伴う軸外収
差の変動を良好に補正することができなくなるので、好
ましくない。条件式（３）の下限値を下回った場合、広
角端状態および望遠端状態において第２レンズ群Ｇ２を
通過する軸外光束の高さの差が小さくなる。その結果、
変倍に伴う軸外収差の変動を良好に補正することができ
なくなるので、好ましくない。If the upper limit of conditional expression (3) is exceeded, the difference in the height of the off-axis luminous flux passing through the second lens group G2 in the telephoto end state becomes small. As a result, fluctuations in off-axis aberration due to zooming cannot be corrected well, which is not preferable. If the lower limit of conditional expression (3) is exceeded, the difference between the heights of the off-axis luminous flux passing through the second lens group G2 in the wide-angle end state and the telephoto end state becomes small. as a result,
It is not preferable because fluctuations in off-axis aberrations due to zooming cannot be satisfactorily corrected.

【００２７】ところで、ズームレンズの近距離合焦方法
として、フロント・フォーカス（ＦＦ）方式、インナー
・フォーカス（ＩＦ）方式、およびリア・フォーカス
（ＲＦ）方式が知られている。そして、レンズ径の比較
的小さいレンズ群を比較的少ない移動量だけ駆動するこ
とにより合焦が可能なインナー・フォーカス方式に関し
て、従来より種々の提案がなされている。インナー・フ
ォーカス方式を用いる場合、フォーカシング群（合焦に
際して駆動されるレンズ群）の移動量（フォーカシング
移動量）を小さくするための条件は、本出願人の出願に
かかる特開平７−３５９７９号公報に示す通りである。
したがって、本発明の変倍光学系においても、広角端状
態から望遠端状態までの各焦点距離範囲においてフォー
カシング群の横倍率を適切な値に規定することにより、
フォーカシング移動量を小さくし、フォーカシング機構
の簡易構成化が達成することができる。As a short-distance focusing method of a zoom lens, a front focus (FF) method, an inner focus (IF) method, and a rear focus (RF) method are known. Various proposals have heretofore been made with respect to an inner focus method capable of focusing by driving a lens group having a relatively small lens diameter by a relatively small amount of movement. When the inner focus method is used, conditions for reducing the moving amount (focusing moving amount) of the focusing group (lens group driven at the time of focusing) are described in Japanese Patent Application Laid-Open No. 7-35979 filed by the present applicant. As shown in FIG.
Therefore, also in the variable power optical system of the present invention, by defining the lateral magnification of the focusing group to an appropriate value in each focal length range from the wide-angle end state to the telephoto end state,
The amount of focusing movement can be reduced, and a simple configuration of the focusing mechanism can be achieved.

【００２８】本発明においては、第２レンズ群Ｇ２ある
いは第３レンズ群Ｇ３をフォーカシング群とした場合、
そのフォーカシング移動量を小さくするために、以下の
条件式（４）を満足することが望ましい。 -0.5＜｛f1＋f2−（d12t−d12w）／２｝／（fw・ft）1/2 ＜0.75 （４） ここで、 d12w：広角端状態における第１レンズ群Ｇ１と第２レン
ズ群Ｇ２との軸上空気間隔 d12t：望遠端状態における第１レンズ群Ｇ１と第２レン
ズ群Ｇ２との軸上空気間隔In the present invention, when the second lens group G2 or the third lens group G3 is a focusing group,
In order to reduce the focusing movement amount, it is desirable to satisfy the following conditional expression (4). −0.5 <{f1 + f2− (d12t−d12w) / 2} / (fw · ft) 1/2 <0.75 (4) where d12w is the difference between the first lens group G1 and the second lens group G2 in the wide-angle end state. On-axis air distance d12t: On-axis air distance between first lens group G1 and second lens group G2 in the telephoto end state.

【００２９】前述の条件に示す通り、本発明において
は、第２レンズ群Ｇ２の横倍率β２および第３レンズ群
Ｇ３の横倍率β３が、−１＜１／β２＜１、−１＜β３
＜１を満足している。したがって、第２レンズ群Ｇ２を
フォーカシング群とする場合に、フォーカシング移動量
を小さくするには、焦点距離範囲において１／β２の値
が０に近い値となることが必要である。また、第３レン
ズ群Ｇ３をフォーカシング群とする場合に、フォーカシ
ング移動量を小さくするには、焦点距離範囲においてβ
３の値が０に近い値となることが必要である。なお、第
２レンズ群Ｇ２の横倍率β２の逆数１／β２が０となる
とき、第３レンズ群Ｇ３の横倍率β３も０である。した
がって、焦点距離範囲の全体に亘ってフォーカシング移
動量を小さくするには、広角端状態から望遠端状態まで
の焦点距離範囲内に１／β２＝０となるレンズ位置状態
を含むことが望ましい。As described above, in the present invention, the lateral magnification β2 of the second lens group G2 and the lateral magnification β3 of the third lens group G3 are −1 <1 / β2 <1, −1 <β3.
<1 is satisfied. Therefore, when the second lens group G2 is used as a focusing group, the value of 1 / β2 needs to be close to 0 in the focal length range in order to reduce the focusing movement amount. Further, when the third lens group G3 is a focusing group, to reduce the focusing movement amount, it is necessary to set β3 in the focal length range.
It is necessary that the value of 3 be close to 0. When the reciprocal 1 / β2 of the lateral magnification β2 of the second lens group G2 is 0, the lateral magnification β3 of the third lens group G3 is also 0. Therefore, in order to reduce the focusing movement amount over the entire focal length range, it is desirable to include a lens position state where 1 / β2 = 0 within the focal length range from the wide-angle end state to the telephoto end state.

【００３０】ところで、第１レンズ群Ｇ１と第２レンズ
群Ｇ２との合成屈折力φ12は、次の式（ｄ）で表され
る。 φ12＝１／ｆ１＋１／ｆ２−ｄ12／（ｆ１・ｆ２） （ｄ） ここで、ｄ12：第１レンズ群Ｇ１と第２レンズ群Ｇ２と
の主点間隔 すなわち、式（ｄ）においてφ12＝０を満足する場合、
次の式（ｅ）に示す関係が成立する。 ｆ１＋ｆ２−ｄ12＝０ （ｅ）Incidentally, the combined refractive power φ12 of the first lens group G1 and the second lens group G2 is represented by the following equation (d). φ12 = 1 / f1 + 1 / f2-d12 / (f1 · f2) (d) where d12 is the distance between the principal points between the first lens group G1 and the second lens group G2. That is, φ12 = 0 in the equation (d). If you are satisfied,
The relationship shown in the following equation (e) is established. f1 + f2-d12 = 0 (e)

【００３１】したがって、フォーカシング群の移動量を
小さくする条件は、第１レンズ群Ｇ１と第２レンズ群Ｇ
２との間隔がΔｄ＝（d12t−d12w）／２になるとき、式
（ｅ）の左辺の値が０に近くなることである。ただし、
d12tおよびd12wは軸上空気間隔であって主点間隔ではな
いので、式（ｅ）の左辺の値が正確に０になる必要はな
い。こうして、条件式（４）の下限値および上限値で規
定される範囲を満足することにより、フォーカシング移
動量を小さくすることが可能となる。なお、さらに効率
的なフォーカシングを行うには、条件式（４）の上限値
を０．５に、下限値を−０．３に設定することが望まし
い。これは、焦点距離が（ｆｗ・ｆｔ）1/2 となる際に
式（ｅ）の左辺をより０に近づけることにより、広角端
状態と望遠端状態とで同一の被写体に対するフォーカシ
ング移動量がほぼ同一の量に近づき、フォーカシング移
動量を減らすことができるからである。Therefore, the condition for reducing the moving amount of the focusing group is that the first lens group G1 and the second lens group G
When the interval from 2 is Δd = (d12t−d12w) / 2, the value on the left side of Expression (e) becomes close to 0. However,
Since d12t and d12w are on-axis air intervals and not principal point intervals, the value on the left side of equation (e) does not need to be exactly zero. Thus, by satisfying the range defined by the lower limit and the upper limit of conditional expression (4), it is possible to reduce the focusing movement amount. In order to perform more efficient focusing, it is desirable to set the upper limit of conditional expression (4) to 0.5 and the lower limit to −0.3. This is because, when the focal length becomes (fw · ft) 1/2 , by making the left side of equation (e) closer to 0, the focusing movement amount for the same subject in the wide-angle end state and the telephoto end state becomes almost equal. This is because the same amount can be approached, and the focusing movement amount can be reduced.

【００３２】本発明においては、第４レンズ群Ｇ４の付
近に開口絞りが配置されるため、第４レンズ群Ｇ４を通
過する軸外光束は光軸の付近を通過する。したがって、
第４レンズ群Ｇ４単独で発生する負の球面収差を良好に
補正することが望ましい。そこで、本発明においては、
第４レンズ群Ｇ４を、少なくとも２枚の正レンズと、少
なくとも１枚の負レンズとで構成することが望ましい。In the present invention, since the aperture stop is arranged near the fourth lens group G4, the off-axis light beam passing through the fourth lens group G4 passes near the optical axis. Therefore,
It is desirable that negative spherical aberration generated by the fourth lens group G4 alone be corrected well. Therefore, in the present invention,
It is desirable that the fourth lens group G4 includes at least two positive lenses and at least one negative lens.

【００３３】別の観点によれば、本発明においては、高
変倍ズームレンズで発生しがちな手ブレ等に起因する像
ブレによる撮影の失敗を防ぐために、光学系のブレを検
出するブレ検出系と駆動手段とをレンズ系に組み合わせ
ることができる。そして、光学系を構成するレンズ群の
うち１つのレンズ群の全体または一部をシフトレンズ群
として偏心させることにより像をシフトさせて、ブレ検
出系により検出された光学系のブレに起因する像ブレ
（像位置の変動）を補正することにより、本発明の変倍
光学系をいわゆる防振光学系とすることが可能である。
また、本発明による変倍光学系は、ズームレンズに限定
されることなく、焦点距離状態が連続的に存在しないバ
リフォーカルズームレンズにも適用することができるこ
とはいうまでもない。According to another aspect, in the present invention, in order to prevent photographing failure due to image blur caused by hand shake or the like which is likely to occur in a high-magnification zoom lens, blur detection for detecting blur of an optical system is performed. The system and the driving means can be combined into a lens system. The image is shifted by decentering the whole or a part of one lens group among the lens groups constituting the optical system as a shift lens group, and the image caused by the blur of the optical system detected by the blur detection system. By correcting blur (fluctuation in image position), the variable power optical system of the present invention can be a so-called anti-vibration optical system.
Further, it is needless to say that the variable power optical system according to the present invention is not limited to a zoom lens, but can be applied to a varifocal zoom lens in which a focal length state does not exist continuously.

【００３４】[0034]

【実施例】以下、本発明の各実施例を、添付図面に基づ
いて説明する。図１は、本発明の各実施例にかかる変倍
光学系の屈折力配分および広角端状態（Ｗ）から望遠端
状態（Ｔ）への変倍時における各レンズ群の移動の様子
を示す図である。図１に示すように、本発明の各実施例
にかかる変倍光学系は、物体側から順に、正の屈折力を
有する第１レンズ群Ｇ１と、負の屈折力を有する第２レ
ンズ群Ｇ２と、負の屈折力を有する第３レンズ群Ｇ３
と、正の屈折力を有する第４レンズ群Ｇ４と、正の屈折
力を有する第５レンズ群Ｇ５とを備えている。そして、
広角端状態から望遠端状態への変倍に際して、第１レン
ズ群Ｇ１と第２レンズ群Ｇ２との間に形成される第１空
気間隔は増大し、第２レンズ群Ｇ２と第３レンズ群Ｇ３
との間に形成される第２空気間隔は増大し、第３レンズ
群Ｇ３と第４レンズ群Ｇ４との間に形成される第３空気
間隔は減少し、第４レンズ群Ｇ４と第５レンズ群Ｇ５と
の間に形成される第４空気間隔は増大するように、各レ
ンズ群が物体側へ移動する。Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a diagram showing a refractive power distribution of a variable power optical system according to each embodiment of the present invention and a state of movement of each lens group during zooming from a wide-angle end state (W) to a telephoto end state (T). It is. As shown in FIG. 1, the variable power optical system according to each example of the present invention includes, in order from the object side, a first lens group G1 having a positive refractive power and a second lens group G2 having a negative refractive power. And a third lens group G3 having a negative refractive power
And a fourth lens group G4 having a positive refractive power and a fifth lens group G5 having a positive refractive power. And
During zooming from the wide-angle end state to the telephoto end state, the first air gap formed between the first lens group G1 and the second lens group G2 increases, and the second lens group G2 and the third lens group G3.
Is increased, the third air gap formed between the third lens group G3 and the fourth lens group G4 is reduced, and the fourth lens group G4 and the fifth lens are separated. Each lens group moves toward the object side such that the fourth air gap formed between the lens group and the group G5 increases.

【００３５】各実施例において、非球面は、光軸に垂直
な方向の高さをｙ、高さｙにおける光軸方向の変位量
（サグ量）をＳ（ｙ）、基準の曲率半径をＲ、円錐係数
をκ、ｎ次の非球面係数をＣn としたとき、以下の数式
（ｆ）で表される。In each of the embodiments, the aspheric surface has a height y in the direction perpendicular to the optical axis, a displacement (sag amount) in the optical axis direction at the height y of S (y), and a reference radius of curvature of R. , The conic coefficient is κ, and the nth-order aspherical coefficient is Cn, and is expressed by the following equation (f).

【数１】 Ｓ（ｙ）＝（ｙ2 ／Ｒ）／｛１＋（１−κ・ｙ2 ／Ｒ2 ）1/2 ｝ ＋Ｃ2 ・ｙ2 ＋Ｃ4 ・ｙ4 ＋Ｃ6 ・ｙ6 ＋Ｃ8 ・ｙ8 ＋Ｃ10・ｙ10＋・・・ （ｆ） 各実施例において、非球面には面番号の右側に＊印を付
している。[Number 1] S (y) = (y 2 / R) / {1+ (1-κ · y 2 / R 2) 1/2} + C 2 · y 2 + C 4 · y 4 + C 6 · y 6 + C 8 · y 8 + C 10 · y 10 + ··· (f) in each example, the aspherical surface is provided with mark * on the right side of the surface number.

【００３６】〔第１実施例〕図２は、本発明の第１実施
例にかかる変倍光学系の構成を示す図である。図２の変
倍光学系は、物体側から順に、物体側に凸面を向けた負
メニスカスレンズと物体側に凸面を向けた正メニスカス
レンズとの接合正レンズＬ11、および物体側に凸面を向
けた正メニスカスレンズＬ12からなる第１レンズ群Ｇ１
と、物体側に凸面を向けた負メニスカスレンズＬ21、両
凹レンズＬ22、および両凸レンズＬ23からなる第２レン
ズ群Ｇ２と、両凹レンズと物体側に凸面を向けた正メニ
スカスレンズとの接合負レンズＬ３からなる第３レンズ
群Ｇ３と、両凸レンズＬ41、両凸レンズＬ42、および両
凹レンズＬ43からなる第４レンズ群Ｇ４と、両凸レンズ
Ｌ51、両凸レンズＬ52、物体側に凸面を向けた負メニス
カスレンズＬ53、両凸レンズＬ54、および物体側に凹面
を向けた負メニスカスレンズＬ55からなる第５レンズ群
Ｇ５とから構成されている。[First Embodiment] FIG. 2 is a diagram showing a configuration of a variable power optical system according to a first embodiment of the present invention. The variable power optical system of FIG. 2 includes, in order from the object side, a cemented positive lens L11 of a negative meniscus lens having a convex surface facing the object side and a positive meniscus lens having a convex surface facing the object side, and a convex surface facing the object side. First lens group G1 composed of positive meniscus lens L12
And a second lens group G2 including a negative meniscus lens L21 having a convex surface facing the object side, a biconcave lens L22, and a biconvex lens L23, and a cemented negative lens L3 of a biconcave lens and a positive meniscus lens having a convex surface facing the object side. A fourth lens group G4 including a biconvex lens L41, a biconvex lens L42, and a biconcave lens L43; a biconvex lens L51, a biconvex lens L52; a negative meniscus lens L53 having a convex surface facing the object side; The fifth lens unit G5 includes a biconvex lens L54 and a negative meniscus lens L55 having a concave surface facing the object side.

【００３７】また、開口絞りＳは、第３レンズ群Ｇ３と
第４レンズ群Ｇ４との間に配置され、広角端状態から望
遠端状態への変倍に際して第４レンズ群Ｇ４と一体的に
移動する。図２は、広角端状態における各レンズ群の位
置関係を示しており、望遠端状態への変倍時には図１に
矢印で示すズーム軌道に沿って光軸上を移動する。ま
た、第３レンズ群Ｇ３を光軸に沿って移動させることに
より、フォーカシング（合焦）を行っている。The aperture stop S is disposed between the third lens group G3 and the fourth lens group G4, and moves together with the fourth lens group G4 when zooming from the wide-angle end state to the telephoto end state. I do. FIG. 2 shows the positional relationship between the lens groups in the wide-angle end state, and moves on the optical axis along a zoom trajectory indicated by an arrow in FIG. 1 during zooming to the telephoto end state. Focusing is performed by moving the third lens group G3 along the optical axis.

【００３８】次の表（１）に、本発明の第１実施例の諸
元の値を掲げる。表（１）において、ｆは焦点距離を、
ＦNOはＦナンバーを、２ωは画角を、Ｂｆはバックフォ
ーカスを、Ｄ0 は物体と最も物体側の面との光軸に沿っ
た距離をそれぞれ表している。さらに、面番号は光線の
進行する方向に沿った物体側からのレンズ面の順序を、
屈折率およびアッベ数はそれぞれｄ線（λ＝５８７．６
ｎｍ）に対する値を示している。Table 1 below summarizes the data values of the first embodiment of the present invention. In Table (1), f is the focal length,
FNO represents the F number, 2ω represents the angle of view, Bf represents the back focus, and D0 represents the distance along the optical axis between the object and the surface closest to the object. Furthermore, the surface number indicates the order of the lens surface from the object side along the direction in which the light rays travel,
The refractive index and Abbe number are each d-line (λ = 587.6).
nm).

【００３９】[0039]

【表１】 ｆ＝36.00 〜87.50 〜175.00〜242.50 ＦNO＝ 3.63 〜 5.00 〜 5.63〜 5.91 ２ω＝63.80 〜27.58 〜13.99 〜 10.02° 面番号 曲率半径 面間隔 屈折率 アッベ数 1 80.9890 1.875 1.84666 23.83 2 48.9190 7.500 1.65160 58.44 3 188.3542 0.125 4 62.0956 5.000 1.69680 55.48 5 194.8188 (D5= 可変) 6* 214.1510 1.875 1.77250 49.61 7 20.7737 5.125 8 -184.8288 1.375 1.83500 42.98 9 62.8835 0.125 10 34.5887 3.750 1.78470 26.06 11 -110.2498 (D11=可変) 12 -31.8685 1.250 1.83500 42.98 13 35.7163 2.750 1.84666 23.83 14 622.9335 (D14=可変) 15 ∞ 0.875 （開口絞りＳ） 16 37.8685 3.750 1.48749 70.44 17 -50.6346 0.125 18 37.4303 3.750 1.48749 70.44 19 -135.8284 1.250 20 -42.1918 1.500 1.80610 33.27 21 196.9209 (D21=可変) 22* 33.2823 4.125 1.48749 70.44 23 -53.4455 1.250 24 39.5636 3.750 1.48749 70.44 25 -84.2589 0.125 26 136.4961 1.875 1.83500 42.98 27 22.6633 12.500 28 291.4677 2.500 1.84666 23.83 29 -129.4440 3.250 30 -22.5475 1.500 1.77250 49.61 31 -39.1697 (Bf) （非球面データ） κ Ｃ2 Ｃ4 6 面 0.0000 0.0000 +3.59194×10-6 Ｃ6 Ｃ8 Ｃ10 -3.39411×10-9 +1.85240×10-11 -2.00749×10-14 κ Ｃ2 Ｃ4 22面 1.5645 0.0000 -1.63820×10-5 Ｃ6 Ｃ8 Ｃ10 -1.20340×10-8 +9.72219×10-11 -3.45087×10-13 （変倍における可変間隔） ｆ 35.9992 87.4969 174.9924 242.4890 D5 2.5000 22.2716 38.9528 44.2319 D11 3.2478 3.7500 5.7286 6.2500 D14 26.2348 14.3758 6.8524 2.1875 D21 11.7914 5.1190 2.1064 1.2500 Bf 33.7487 58.3556 68.4495 73.2015 （撮影倍率−１／３０倍時の第３レンズ群Ｇ３のフォーカシング移動量） 焦点距離ｆ 35.9992 87.4969 174.9924 242.4890 Ｄ0 1031.8764 2506.8358 4962.2252 6845.6214 移動量 0.7604 0.6736 0.9681 1.1966 ただし、移動量の符号は物体側から像側への移動を正とする （条件対応値） ｆ１＝ ９３．７１９５ ｆ２＝−５４．５６２３ ｆ３＝−３５．８６９８ （１）（ｆ２−ｆ３）／（ｆ２・ｆ３）1/2 ＝−０．２００ （２）ｆ１／（ｆｗ・ｆｔ）1/2 ＝ １．００３ （３）（d23t−d23w）（fw・ft）1/2 ／（f2・f3） ＝ ０．１４３ （４）｛f1＋f2−（d12t−d12w）／２｝／（fw・ft）1/2 ＝ ０．３９２Table 1 f = 36.00-87.50-175.00-242.50 FNO = 3.63-5.00-5.63-5.91 2ω = 63.80-27.58-13.99-10.02 ° Surface number Curvature radius Surface spacing Refractive index Abbe number 1 80.9890 1.875 1.84666 23.83 2 48.9190 7.500 1.65160 58.44 3 188.3542 0.125 4 62.0956 5.000 1.69680 55.48 5 194.8188 (D5 = variable) 6 * 214.1510 1.875 1.77250 49.61 7 20.7737 5.125 8 -184.8288 1.375 1.83500 42.98 9 62.8835 0.125 10 34.5887 3.750 1.78470 26.06 11 -110.2498 (D11 = variable) 31.8685 1.250 1.83500 42.98 13 35.7163 2.750 1.84666 23.83 14 622.9335 (D14 = variable) 15 ∞ 0.875 (aperture stop S) 16 37.8685 3.750 1.48749 70.44 17 -50.6346 0.125 18 37.4303 3.750 1.48749 70.44 19 -135.8284 1.250 20 -42.1918 1.500 1.6.910 33.21 19 (D21 = variable) 22 * 33.2823 4.125 1.48749 70.44 23 -53.4455 1.250 24 39.5636 3.750 1.48749 70.44 25 -84.2589 0.125 26 136.4961 1.875 1.83500 42.98 27 22.6633 12.500 28 291.4677 2.500 1.84666 23.83 29 -129.4440 3.250 30 -22.5475 1.500 1.7739 49.61 (Bf) (Aspherical data) κ C 2 C 4 6 surface 0.0000 0.0000 + 3.59194 × 10 -6 C 6 C 8 C 10 -3.39411 × 10 -9 +1.85 240 × 10 -11 -2.00749 × 10 -14 κ C 2 C 4 22 surface 1.5645 0.0000 -1.63820 × 10 -5 C 6 C 8 C 10 -1.20 340 × 10 -8 +9.72 219 × 10 -11 -3.45087 × 10 -13 (variable interval in variable magnification) f 35.9992 87.4969 174.9924 242.4890 D5 2.5000 22.2716 38.9528 44.2319 D11 3.2478 3.7500 5.7286 6.2500 D14 26.2348 14.3758 6.8524 2.1875 D21 11.7914 5.1190 2.1064 1.2500 Bf 33.7487 58.3556 68.4495 73.2015 (Focus moving distance of the third lens group G3 at a photographing magnification of -1 / 30x) Focal length f 35.9992 87.4969 174.9924 24890 D0 1031.8764 2506.8358 4962.2252 6845.6214 Movement amount 0.7604 0.6736 0.9681 1.1966 However, the sign of the movement amount is positive from the object side to the image side (value corresponding to the condition). F1 = 93.7195 f2 = -54.5623 f3 = -35 .8698 (1) (f2−f3) / (f2 · f) ) 1/2 = -0.200 (2) f1 / (fw · ft) 1/2 = 1.003 (3) (d23t-d23w) (fw · ft) 1/2 / (f2 · f3) = 0 .143 (4) {f1 + f2- (d12t-d12w) / 2} / (fw.ft) 1/2 = 0.392

【００４０】図３乃至図１０は、ｄ線（λ＝５８７．６
ｎｍ）に対する第１実施例の諸収差図である。図３は広
角端状態（最短焦点距離状態）における無限遠合焦状態
での諸収差図であり、図４は第１中間焦点距離状態にお
ける無限遠合焦状態での諸収差図であり、図５は第２中
間焦点距離状態における無限遠合焦状態での諸収差図で
あり、図６は望遠端状態（最長焦点距離状態）における
無限遠合焦状態での諸収差図である。また、図７は広角
端状態における撮影倍率−１／３０倍での諸収差図であ
り、図８は第１中間焦点距離状態における撮影倍率−１
／３０倍での諸収差図であり、図９は第２中間焦点距離
状態における撮影倍率−１／３０倍での諸収差図であり
図１０は望遠端状態における撮影倍率−１／３０倍での
諸収差図である。FIGS. 3 to 10 show the d-line (λ = 587.6).
FIG. 7 is a diagram illustrating various aberrations of the first example with respect to (nm). FIG. 3 is a diagram illustrating various aberrations in the infinity in-focus condition in the wide-angle end state (the shortest focal length state), and FIG. 4 is a diagram illustrating various aberrations in the infinity in-focus condition in the first intermediate focal length state. 5 is a diagram of various aberrations in the second intermediate focal length state in an infinity in-focus state, and FIG. 6 is a diagram of various aberrations in a telephoto end state (longest focal length state) in an infinity in-focus state. FIG. 7 is a diagram illustrating various aberrations at a photographing magnification of −1 / 30 × in the wide-angle end state, and FIG. 8 is a photographing magnification of −1 in the first intermediate focal length state.
FIG. 9 is a graph showing various aberrations at a photographing magnification of −1 / 30 × in the second intermediate focal length state, and FIG. 10 is a graph showing various aberrations at a photographing magnification of −1 / 30 × in the telephoto end state. FIG. 4 is a diagram of various aberrations of FIG.

【００４１】各収差図において、ＦNOはＦナンバーを、
ＮＡは開口数を、Ｙは像高を、Ａは各像高に対する半画
角を、Ｈは各像高に対する物体高をそれぞれ示してい
る。また、非点収差を示す収差図において、実線はサジ
タル像面を示し、破線はメリディオナル像面を示してい
る。さらに、球面収差を示す収差図において、破線はサ
インコンディション（正弦条件）を示している。各収差
図から明らかなように、本実施例では、各撮影距離状態
および各焦点距離状態において諸収差が良好に補正され
ていることがわかる。In each aberration diagram, FNO represents an F number,
NA indicates the numerical aperture, Y indicates the image height, A indicates the half angle of view for each image height, and H indicates the object height for each image height. In the aberration diagram showing astigmatism, a solid line indicates a sagittal image plane, and a broken line indicates a meridional image plane. Further, in the aberration diagram showing the spherical aberration, a broken line indicates a sine condition (sine condition). As is clear from the aberration diagrams, in the present embodiment, various aberrations are satisfactorily corrected in each shooting distance state and each focal length state.

【００４２】〔第２実施例〕図１１は、本発明の第２実
施例にかかる変倍光学系の構成を示す図である。図１１
の変倍光学系は、物体側から順に、物体側に凸面を向け
た負メニスカスレンズと物体側に凸面を向けた正メニス
カスレンズとの接合正レンズＬ11、および物体側に凸面
を向けた正メニスカスレンズＬ12からなる第１レンズ群
Ｇ１と、物体側に凸面を向けた負メニスカスレンズＬ2
1、両凹レンズＬ22、および両凸レンズＬ23からなる第
２レンズ群Ｇ２と、両凹レンズと物体側に凸面を向けた
正メニスカスレンズとの接合負レンズＬ３からなる第３
レンズ群Ｇ３と、両凸レンズＬ41、物体側に凸面を向け
た正メニスカスレンズＬ42、および物体側に凹面を向け
た負メニスカスレンズＬ43からなる第４レンズ群Ｇ４
と、両凸レンズＬ51、両凸レンズと両凹レンズとの接合
レンズＬ52、両凸レンズＬ53、および物体側に凹面を向
けた負メニスカスレンズＬ54からなる第５レンズ群Ｇ５
とから構成されている。[Second Embodiment] FIG. 11 is a view showing the arrangement of a variable power optical system according to a second embodiment of the present invention. FIG.
The variable magnification optical system includes, in order from the object side, a cemented positive lens L11 of a negative meniscus lens having a convex surface facing the object side and a positive meniscus lens having a convex surface facing the object side, and a positive meniscus having a convex surface facing the object side. A first lens group G1 including a lens L12 and a negative meniscus lens L2 having a convex surface facing the object side;
1. A second lens group G2 including a biconcave lens L22 and a biconvex lens L23, and a third negative lens L3 including a cemented biconcave lens and a positive meniscus lens having a convex surface facing the object side.
A fourth lens group G4 including a lens group G3, a biconvex lens L41, a positive meniscus lens L42 having a convex surface facing the object side, and a negative meniscus lens L43 having a concave surface facing the object side.
A fifth lens group G5 including a biconvex lens L51, a cemented lens L52 of a biconvex lens and a biconcave lens, a biconvex lens L53, and a negative meniscus lens L54 having a concave surface facing the object side.
It is composed of

【００４３】また、開口絞りＳは、第３レンズ群Ｇ３と
第４レンズ群Ｇ４との間に配置され、広角端状態から望
遠端状態への変倍に際して第４レンズ群Ｇ４と一体的に
移動する。図１１は、広角端状態における各レンズ群の
位置関係を示しており、望遠端状態への変倍時には図１
に矢印で示すズーム軌道に沿って光軸上を移動する。ま
た、第３レンズ群Ｇ３を光軸に沿って移動させることに
より、フォーカシング（合焦）を行っている。The aperture stop S is disposed between the third lens unit G3 and the fourth lens unit G4, and moves together with the fourth lens unit G4 when zooming from the wide-angle end state to the telephoto end state. I do. FIG. 11 shows the positional relationship between the lens groups in the wide-angle end state.
Move on the optical axis along the zoom trajectory indicated by the arrow. Focusing is performed by moving the third lens group G3 along the optical axis.

【００４４】次の表（２）に、本発明の第２実施例の諸
元の値を掲げる。表（２）において、ｆは焦点距離を、
ＦNOはＦナンバーを、２ωは画角を、Ｂｆはバックフォ
ーカスを、Ｄ0 は物体と最も物体側の面との光軸に沿っ
た距離をそれぞれ表している。さらに、面番号は光線の
進行する方向に沿った物体側からのレンズ面の順序を、
屈折率およびアッベ数はそれぞれｄ線（λ＝５８７．６
ｎｍ）に対する値を示している。Table 2 below summarizes data values of the second embodiment of the present invention. In Table (2), f is the focal length,
FNO represents the F number, 2ω represents the angle of view, Bf represents the back focus, and D0 represents the distance along the optical axis between the object and the surface closest to the object. Furthermore, the surface number indicates the order of the lens surface from the object side along the direction in which the light rays travel,
The refractive index and Abbe number are each d-line (λ = 587.6).
nm).

【００４５】[0045]

【表２】 ｆ＝36.00 〜75.00 〜112.50〜171.25 ＦNO＝ 3.90 〜 5.02 〜 5.50〜 5.87 ２ω＝63.83 〜31.40 〜21.12 〜 13.92° 面番号 曲率半径 面間隔 屈折率 アッベ数 1 121.0353 1.875 1.84666 23.83 2 53.6309 7.500 1.65160 58.44 3 903.2446 0.125 4 51.9503 5.000 1.74810 52.30 5 192.6792 (D5= 可変) 6 126.1037 1.875 1.77250 49.61 7 18.3230 5.250 8 -89.6368 1.375 1.83500 42.98 9 78.6459 0.125 10 29.8410 3.938 1.76182 26.55 11 -172.2154 (D11=可変) 12 -37.1905 1.250 1.83500 42.98 13 31.6473 2.750 1.84666 23.83 14 240.1302 (D14=可変) 15 ∞ 0.875 （開口絞りＳ） 16 26.9305 4.250 1.48749 70.44 17 -40.4244 0.125 18 39.9492 2.250 1.48749 70.44 19 253.3137 1.375 20 -30.0234 1.500 1.80610 33.27 21 -483.6197 (D21=可変) 22 26.5109 5.625 1.51680 64.20 23 -53.4455 1.250 24 39.5636 3.750 1.48749 70.44 25 136.4961 1.875 1.83500 42.98 26 22.6633 12.500 27 55.9783 2.875 1.75692 31.62 28 -89.4049 3.500 29 -15.4360 1.500 1.77250 49.61 30 -25.3558 (Bf) （変倍における可変間隔） ｆ 35.9999 74.9988 112.4982 171.2475 D5 2.5000 16.5419 24.5701 31.2236 D11 2.8282 3.7500 5.6280 7.5000 D14 24.6167 14.8946 10.1755 4.3750 D21 9.3022 5.8449 4.5679 3.9252 Bf 34.7531 50.5947 56.7812 61.6628 （撮影倍率−１／３０倍時の第３レンズ群Ｇ３のフォーカシング移動量） 焦点距離ｆ 35.9999 74.9988 112.4982 171.2475 Ｄ0 1032.8374 2148.9448 3208.8149 4856.2273 移動量 0.8007 0.7648 0.8867 1.1324 ただし、移動量の符号は物体側から像側への移動を正とする （条件対応値） ｆ１＝ ７０．０８８７ ｆ２＝−４３．９７１２ ｆ３＝−３８．７９９５ （１）（ｆ２−ｆ３）／（ｆ２・ｆ３）1/2 ＝−０．０６６ （２）ｆ１／（ｆｗ・ｆｔ）1/2 ＝ ０．８９３ （３）（d23t−d23w）（fw・ft）1/2 ／（f2・f3） ＝ ０．２１５ （４）｛f1＋f2−（d12t−d12w）／２｝／（fw・ft）1/2 ＝ ０．１５０[Table 2] f = 36.00-75.00-112.50-171.25 FNO = 3.90-5.02-5.50-5.87 2ω = 63.83-31.40-21.12-13.92 ° Surface number Curvature radius Surface spacing Refractive index Abbe number 1 121.0353 1.875 1.84666 23.83 2 53.6309 7.500 1.65160 58.44 3 903.2446 0.125 4 51.9503 5.000 1.74810 52.30 5 192.6792 (D5 = variable) 6 126.1037 1.875 1.77250 49.61 7 18.3230 5.250 8 -89.6368 1.375 1.83500 42.98 9 78.6459 0.125 10 29.8410 3.938 1.76182 26.55 11 -172.2154 (D11 = 905) 12 1.250 1.83500 42.98 13 31.6473 2.750 1.84666 23.83 14 240.1302 (D14 = variable) 15 ∞ 0.875 (Aperture stop S) 16 26.9305 4.250 1.48749 70.44 17 -40.4244 0.125 18 39.9492 2.250 1.48749 70.44 19 253.3137 1.375 20 -30.0234 1.500 1.80610 33.27 21 -483.6197 ( (D21 = variable) 22 26.5109 5.625 1.51680 64.20 23 -53.4455 1.250 24 39.5636 3.750 1.48749 70.44 25 136.4961 1.875 1.83500 42.98 26 22.6633 12.500 27 55.9783 2.875 1.75692 31.62 28 -89.4049 3.500 29 -15.4360 1.500 1.77250 49.61 30-25.3558B In F 35.9999 74.9988 112.4982 171.2475 D5 2.5000 16.5419 24.5701 31.2236 D11 2.8282 3.7500 5.6280 7.5000 D14 24.6167 14.8946 10.1755 4.3750 D21 9.3022 5.8449 4.5679 3.9252 Bf 34.7531 50.5947 56.7812 61.6628 (3rd lens at 1 / 330G at 1 / 30x) Focusing movement amount) Focal length f 35.9999 74.9988 112.4982 171.2475 D0 1032.8374 2148.9448 3208.8149 4856.2273 Movement amount 0.8007 0.7648 0.8867 1.1324 However, the sign of the movement amount is positive when moving from the object side to the image side (Conditional value) f1 = 70. 0887 f2 = −43.9712 f3 = −38.77995 (1) (f2−f3) / (f2 · f3) 1/2 = −0.066 (2) f1 / (fw · ft) 1/2 = 0 .893 (3) (d23t−d23w) (fw · ft) 1/2 /(f2·f3)=0.215 (4) {f1 + f2− (d12t−d12w) / 2} / (fw · ft) 1 / 2 = 0.150

【００４６】図１２乃至図１９は、ｄ線（λ＝５８７．
６ｎｍ）に対する第２実施例の諸収差図である。図１２
は広角端状態における無限遠合焦状態での諸収差図であ
り、図１３は第１中間焦点距離状態における無限遠合焦
状態での諸収差図であり、図１４は第２中間焦点距離状
態における無限遠合焦状態での諸収差図であり、図１５
は望遠端状態における無限遠合焦状態での諸収差図であ
る。また、図１６は広角端状態における撮影倍率−１／
３０倍での諸収差図であり、図１７は第１中間焦点距離
状態における撮影倍率−１／３０倍での諸収差図であ
り、図１８は第２中間焦点距離状態における撮影倍率−
１／３０倍での諸収差図であり図１９は望遠端状態にお
ける撮影倍率−１／３０倍での諸収差図である。FIGS. 12 to 19 show the d-line (λ = 587.
FIG. 9 is a diagram illustrating various aberrations of the second example with respect to 6 nm). FIG.
FIG. 13 is a diagram showing various aberrations in the infinity in-focus condition in the wide-angle end state, FIG. 13 is a diagram showing various aberrations in the infinity in-focus condition in the first intermediate focal length condition, and FIG. FIG. 15 is a diagram illustrating various aberrations at the time of focusing on infinity in FIG.
FIG. 4 is a diagram of various aberrations in an infinity in-focus state in a telephoto end state. FIG. 16 shows a photographing magnification of −1 / in the wide-angle end state.
FIG. 17 is a diagram of various aberrations at 30 ×, FIG. 17 is a diagram of various aberrations at a photographing magnification of 1/30 × in the first intermediate focal length state, and FIG.
FIGS. 19A and 19B are various aberration diagrams at 1/30 ×, and FIG. 19 is various aberration diagrams at a photographing magnification of −1 / 30 × in the telephoto end state.

【００４７】各収差図において、ＦNOはＦナンバーを、
ＮＡは開口数を、Ｙは像高を、Ａは各像高に対する半画
角を、Ｈは各像高に対する物体高をそれぞれ示してい
る。また、非点収差を示す収差図において、実線はサジ
タル像面を示し、破線はメリディオナル像面を示してい
る。さらに、球面収差を示す収差図において、破線はサ
インコンディション（正弦条件）を示している。各収差
図から明らかなように、本実施例では、各撮影距離状態
および各焦点距離状態において諸収差が良好に補正され
ていることがわかる。In each aberration diagram, FNO represents an F number,
NA indicates the numerical aperture, Y indicates the image height, A indicates the half angle of view for each image height, and H indicates the object height for each image height. In the aberration diagram showing astigmatism, a solid line indicates a sagittal image plane, and a broken line indicates a meridional image plane. Further, in the aberration diagram showing the spherical aberration, a broken line indicates a sine condition (sine condition). As is clear from the aberration diagrams, in the present embodiment, various aberrations are satisfactorily corrected in each shooting distance state and each focal length state.

【００４８】[0048]

【効果】以上説明したように、本発明によれば、小型
で、高変倍化が可能で、且つ近距離合焦が可能な変倍光
学系を実現することができる。As described above, according to the present invention, it is possible to realize a variable-magnification optical system which is compact, can have a high zoom ratio, and can focus on a short distance.

【図面の簡単な説明】[Brief description of the drawings]

【図１】本発明の各実施例にかかる変倍光学系の屈折力
配分および広角端状態（Ｗ）から望遠端状態（Ｔ）への
変倍時における各レンズ群の移動の様子を示す図であ
る。FIG. 1 is a diagram showing a refractive power distribution of a variable power optical system according to each embodiment of the present invention and a state of movement of each lens group during zooming from a wide-angle end state (W) to a telephoto end state (T). It is.

【図２】本発明の第１実施例にかかる変倍光学系の構成
を示す図である。FIG. 2 is a diagram illustrating a configuration of a variable power optical system according to a first example of the present invention.

【図３】第１実施例の広角端状態における無限遠合焦状
態での諸収差図である。FIG. 3 is a diagram illustrating various aberrations of the first example in a focused state at infinity in a wide-angle end state.

【図４】第１実施例の第１中間焦点距離状態における無
限遠合焦状態での諸収差図である。FIG. 4 is a diagram illustrating various aberrations of the first example in a first intermediate focal length state in an infinity in-focus state;

【図５】第１実施例の第２中間焦点距離状態における無
限遠合焦状態での諸収差図である。FIG. 5 is a diagram illustrating various aberrations of the first example in a second intermediate focal length state in an infinity in-focus state;

【図６】第１実施例の望遠端状態における無限遠合焦状
態での諸収差図である。FIG. 6 is a diagram illustrating various aberrations of the first example at a telephoto end in an infinity in-focus state;

【図７】第１実施例の広角端状態における撮影倍率−１
／３０倍での諸収差図である。FIG. 7 is a photographing magnification-1 in the wide-angle end state of the first embodiment.
It is a graph of various aberrations at / 30 time.

【図８】第１実施例の第１中間焦点距離状態における撮
影倍率−１／３０倍での諸収差図である。FIG. 8 is a diagram illustrating various aberrations at a magnification of −1/30 in the first intermediate focal length state of the first example.

【図９】第１実施例の第２中間焦点距離状態における撮
影倍率−１／３０倍での諸収差図である。FIG. 9 is a diagram illustrating various aberrations at a magnification of −1/30 in the second intermediate focal length state of the first example.

【図１０】第１実施例の望遠端状態における撮影倍率−
１／３０倍での諸収差図である。FIG. 10 shows a photographing magnification in the telephoto end state of the first embodiment.
It is a some-aberration figure at 1/30 time.

【図１１】本発明の第２実施例にかかる変倍光学系の構
成を示す図である。FIG. 11 is a diagram showing a configuration of a variable power optical system according to Example 2 of the present invention.

【図１２】第２実施例の広角端状態における無限遠合焦
状態での諸収差図である。FIG. 12 is a diagram illustrating various aberrations of the second example in a state of being focused on infinity in a wide-angle end state.

【図１３】第２実施例の第１中間焦点距離状態における
無限遠合焦状態での諸収差図である。FIG. 13 is a diagram illustrating various aberrations of the second example in a first intermediate focal length state in an infinity in-focus state;

【図１４】第２実施例の第２中間焦点距離状態における
無限遠合焦状態での諸収差図である。FIG. 14 is a diagram illustrating various aberrations of the second example in a second intermediate focal length state in an infinity in-focus state;

【図１５】第２実施例の望遠端状態における無限遠合焦
状態での諸収差図である。FIG. 15 is a diagram illustrating various aberrations of the second example at a telephoto end in an infinity in-focus condition;

【図１６】第２実施例の広角端状態における撮影倍率−
１／３０倍での諸収差図である。FIG. 16 shows a photographing magnification in the wide-angle end state according to the second embodiment.
It is a some-aberration figure at 1/30 time.

【図１７】第２実施例の第１中間焦点距離状態における
撮影倍率−１／３０倍での諸収差図である。FIG. 17 is a diagram illustrating various aberrations at a magnification of −1/30 in the first intermediate focal length state in the second example.

【図１８】第２実施例の第２中間焦点距離状態における
撮影倍率−１／３０倍での諸収差図である。FIG. 18 is a diagram illustrating various aberrations at a magnification of −1/30 in the second intermediate focal length state according to the second example.

【図１９】第２実施例の望遠端状態における撮影倍率−
１／３０倍での諸収差図である。FIG. 19 is a photographing magnification in the telephoto end state of the second embodiment.
It is a some-aberration figure at 1/30 time.

【符号の説明】[Explanation of symbols]

Ｇ１ 第１レンズ群 Ｇ２ 第２レンズ群 Ｇ３ 第３レンズ群 Ｇ４ 第４レンズ群 Ｇ５ 第５レンズ群 Ｌｉ 各レンズ成分 Ｓ 開口絞り G1 first lens group G2 second lens group G3 third lens group G4 fourth lens group G5 fifth lens group Li each lens component S aperture stop

Claims (6)

【特許請求の範囲】[Claims] 【請求項１】 物体側から順に、正の屈折力を有する第
１レンズ群Ｇ１と、負の屈折力を有する第２レンズ群Ｇ
２と、負の屈折力を有する第３レンズ群Ｇ３と、正の屈
折力を有する第４レンズ群Ｇ４と、正の屈折力を有する
第５レンズ群Ｇ５とを備え、 広角端状態から望遠端状態への変倍に際して、前記第１
レンズ群Ｇ１と前記第２レンズ群Ｇ２との間に形成され
る第１空気間隔は増大し、前記第２レンズ群Ｇ２と前記
第３レンズ群Ｇ３との間に形成される第２空気間隔は増
大し、前記第３レンズ群Ｇ３と前記第４レンズ群Ｇ４と
の間に形成される第３空気間隔は減少し、前記第４レン
ズ群Ｇ４と前記第５レンズ群Ｇ５との間に形成される第
４空気間隔は変化するように、少なくとも前記第１レン
ズ群Ｇ１および前記第５レンズ群Ｇ５は物体側へ移動
し、 前記第１レンズ群Ｇ１の焦点距離をｆ１とし、前記第２
レンズ群Ｇ２の焦点距離をｆ２とし、前記第３レンズ群
Ｇ３の焦点距離をｆ３とし、広角端状態におけるレンズ
系全体の焦点距離をｆｗとし、望遠端状態におけるレン
ズ系全体の焦点距離をｆｔとしたとき、 −０．５＜（ｆ２−ｆ３）／（ｆ２・ｆ３）1/2 ＜０．３ ０．８＜ｆ１／（ｆｗ・ｆｔ）1/2 ＜１．４ の条件を満足することを特徴とする変倍光学系。1. A first lens group G1 having a positive refractive power and a second lens group G having a negative refractive power in order from the object side.
2, a third lens group G3 having a negative refractive power, a fourth lens group G4 having a positive refractive power, and a fifth lens group G5 having a positive refractive power. Upon zooming to a state, the first
The first air gap formed between the lens group G1 and the second lens group G2 increases, and the second air gap formed between the second lens group G2 and the third lens group G3 increases. The third air gap formed between the third lens group G3 and the fourth lens group G4 decreases, and the third air gap formed between the third lens group G4 and the fifth lens group G5 increases. At least the first lens group G1 and the fifth lens group G5 move toward the object side so that the fourth air gap changes, and the focal length of the first lens group G1 is f1, and the second lens group G1 is the second lens group G1.
The focal length of the lens group G2 is f2, the focal length of the third lens group G3 is f3, the focal length of the entire lens system in the wide-angle end state is fw, and the focal length of the entire lens system in the telephoto end state is ft. Satisfies the following condition: -0.5 <(f2-f3) / (f2 · f3) 1/2 <0.3 0.8 <f1 / (fw · ft) 1/2 <1.4 A variable power optical system characterized by the following. 【請求項２】 前記第１レンズ群Ｇ１と前記第４レンズ
群Ｇ４との間に配置されるレンズ群のうちの１つのレン
ズ群を光軸に沿って移動させて、近距離物体への合焦を
行うことを特徴とする請求項１に記載の変倍光学系。2. One of the lens groups disposed between the first lens group G1 and the fourth lens group G4 is moved along the optical axis to form a lens group close to an object at a short distance. The variable power optical system according to claim 1, wherein focusing is performed. 【請求項３】 広角端状態における前記第２レンズ群Ｇ
２と前記第３レンズ群Ｇ３との軸上空気間隔をd23wと
し、望遠端状態における前記第２レンズ群Ｇ２と前記第
３レンズ群Ｇ３との軸上空気間隔をd23tとし、前記第２
レンズ群Ｇ２の焦点距離をｆ２とし、前記第３レンズ群
Ｇ３の焦点距離をｆ３とし、広角端状態におけるレンズ
系全体の焦点距離をｆｗとし、望遠端状態におけるレン
ズ系全体の焦点距離をｆｔとしたとき、 0.07＜（d23t−d23w）（fw・ft）1/2 ／（f2・f3）＜0.35 の条件を満足することを特徴とする請求項１または２に
記載の変倍光学系。3. The second lens group G in a wide-angle end state.
The axial air gap between the second lens group G3 and the third lens group G3 is d23w, and the axial air gap between the second lens group G2 and the third lens group G3 in the telephoto end state is d23t.
The focal length of the lens group G2 is f2, the focal length of the third lens group G3 is f3, the focal length of the entire lens system in the wide-angle end state is fw, and the focal length of the entire lens system in the telephoto end state is ft. The variable-power optical system according to claim 1, wherein a condition of 0.07 <(d23t−d23w) (fw · ft) 1/2 /(f2·f3)<0.35 is satisfied. 【請求項４】 前記第３レンズ群Ｇ３よりも像側で前記
第５レンズ群Ｇ５よりも物体側の光路中に開口絞りが設
けられていることを特徴とする請求項１乃至３のいずれ
か１項に記載の変倍光学系。4. An aperture stop is provided in an optical path on the image side of the third lens group G3 and on the object side of the fifth lens group G5. 2. The variable power optical system according to claim 1. 【請求項５】 広角端状態における前記第１レンズ群Ｇ
１と前記第２レンズ群Ｇ２との軸上空気間隔をd12wと
し、望遠端状態における前記第１レンズ群Ｇ１と前記第
２レンズ群Ｇ２との軸上空気間隔をd12tとし、前記第１
レンズ群Ｇ１の焦点距離をｆ１とし、前記第２レンズ群
Ｇ２の焦点距離をｆ２とし、広角端状態におけるレンズ
系全体の焦点距離をｆｗとし、望遠端状態におけるレン
ズ系全体の焦点距離をｆｔとしたとき、 -0.5＜｛f1＋f2−（d12t−d12w）／２｝／（fw・ft）1/2 ＜0.75 の条件を満足することを特徴とする請求項２に記載の変
倍光学系。5. The first lens group G in a wide-angle end state
The axial air gap between the first lens group G2 and the second lens group G2 is d12w, and the axial air gap between the first lens group G1 and the second lens group G2 in the telephoto end state is d12t.
The focal length of the lens group G1 is f1, the focal length of the second lens group G2 is f2, the focal length of the entire lens system in the wide-angle end state is fw, and the focal length of the entire lens system in the telephoto end state is ft. 3. The variable power optical system according to claim 2, wherein the following condition is satisfied: -0.5 <{f1 + f2- (d12t-d12w) / 2} / (fw.ft) 1/2 <0.75. 【請求項６】 前記第４レンズ群Ｇ４は、少なくとも２
枚の正レンズと、少なくとも１枚の負レンズとを有する
ことを特徴とする請求項１乃至５のいずれか１項に記載
の変倍光学系。6. The fourth lens group G4 has at least two lenses.
The variable power optical system according to any one of claims 1 to 5, comprising at least one positive lens and at least one negative lens.
JP21948296A 1996-08-01 1996-08-01 Variable magnification optical system Expired - Lifetime JP3716418B2 (en)

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