JPH0850245A - Zoom lens - Google Patents

Abstract

PURPOSE:To obtain high optical performance all over the variable power range where the field angle in photographing at a wide angle end is about 74 deg. and variable power is about 3.5 by appropriately setting the lens constitution of each lens group or the variable power share, etc., of each lens group at the time of executing the variable power. CONSTITUTION:This zoom lens is constituted of four lens groups, that is, a 1st group L1 having negative refractive power, a 2nd group L2 having positive refractive power, a 3rd group L3 having positive refractive power and a 4th group L4 having negative refractive power in this order from an object side. In the case of moving the respective lens groups and varying the power, the 2nd group L2 has the highest variable power rate on a condition of DELTAbetai>1 out of the lens groups having the positive refractive power when it is assumed that the lateral magifications at the wide angle end and a telephoto end of the (i)-th group (i>=2) are betaiW and betaiT respectively, and the variable power rate DELTAbetai of the (i)-th group is DELTAbetai=¦betaiT/betaiW¦, and also it is provided with a three-lens bonding lens obtained by bonding two positive lenses or two negative lenses to one lens having the reverse refractive power to them respectively and having the positive refractive power as a whole.

Description

【発明の詳細な説明】Detailed Description of the Invention

【０００１】[0001]

【産業上の利用分野】本発明はレンズシャッターカメ
ラ、ビデオカメラ等に好適な小型の高変倍で広画角のズ
ームレンズに関し、特に撮影画角の広画角化を図ると共
にレンズ全長（第１レンズ面から像面までの距離）の短
縮化を図った携帯性に優れたズームレンズに関するもの
である。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a compact zoom lens having a high zoom ratio and a wide angle of view, which is suitable for a lens shutter camera, a video camera, etc. The present invention relates to a zoom lens which is excellent in portability and has a shortened distance from one lens surface to an image surface.

【０００２】[0002]

【従来の技術】最近レンズシャッターカメラ、ビデオカ
メラ等においては、カメラの小型化に伴いレンズ全長の
短い小型のズームレンズが要求されている。2. Description of the Related Art Recently, in a lens shutter camera, a video camera, etc., a compact zoom lens having a short total lens length has been demanded as the camera becomes smaller.

【０００３】特にレンズシャッターカメラは、ズーム駆
動用の電気回路などの周辺技術の発達などにより、増々
カメラの小型化が進んでおり、それに備わる撮影レンズ
も高変倍でかつコンパクトなズームレンズが要求されて
いる。In particular, the lens shutter camera is becoming smaller and smaller due to the development of peripheral technologies such as an electric circuit for zoom driving, and a photographing lens provided therein is required to have a high zoom ratio and a compact zoom lens. Has been done.

【０００４】従来、レンズシャッター用のズームレンズ
としては正、負の屈折力の２つのレンズ群より成る所謂
２群ズームレンズが主流であった。この２群ズームレン
ズはレンズ構成及び変倍時の移動機構が簡易なため、カ
メラの小型化及び比較的低コストである等の利点があ
る。Conventionally, as a zoom lens for a lens shutter, a so-called two-group zoom lens composed of two lens groups having positive and negative refracting powers has been mainly used. Since the two-group zoom lens has a simple lens structure and a moving mechanism at the time of zooming, it has advantages such as downsizing of the camera and relatively low cost.

【０００５】しかしながら変倍作用を１つのレンズ群の
みで行わなくてはならないため、その変倍比は１．６〜
２倍程度であり、無理に変倍比を拡大することはレンズ
系の大型化を招くと同時に、高い光学性能を保つことが
困難になってくる。However, since the zooming action must be performed by only one lens group, the zooming ratio is 1.6 to
It is about 2 times, and forcibly enlarging the zoom ratio leads to an increase in the size of the lens system, and at the same time, it becomes difficult to maintain high optical performance.

【０００６】２群ズームレンズを基礎とし、第１群を正
の屈折力の２つのレンズ群に分離し、全体として正、
正、負の屈折力の３群構成として高変倍化を狙った３群
ズームレンズが、例えば特開平３−２８２４０９号公
報、特開平４−３７８１０号公報、特開平４−７６５１
１号公報等で提案されている。On the basis of a two-group zoom lens, the first group is divided into two lens groups having a positive refractive power, and the whole group is positive,
A three-group zoom lens aiming at high zooming as a three-group configuration of positive and negative refracting powers is disclosed in, for example, Japanese Patent Laid-Open Nos. 3-282409, 4-37810, and 4-7651.
It is proposed in Japanese Patent Publication No. 1 and the like.

【０００７】しかしながらこのレンズ群構成で例えば半
画角３５°以上の広画角なズームレンズ系を達成しよう
とすると変倍時の入射瞳位置の変化が大きくなる。この
ため、高変倍化を図る際は変倍による収差変動を抑える
ことが大変困難になってくる。However, if an attempt is made to achieve a wide-angle zoom lens system having a half angle of view of 35 ° or more with this lens group configuration, the change in the entrance pupil position during zooming becomes large. For this reason, it becomes very difficult to suppress aberration variation due to zooming when achieving high zooming.

【０００８】この他、多レンズ群化により広角端の半画
角を３８°程度、変倍比を３．５倍程度とし、広画角化
及び高変倍化を図ったズームレンズが、例えば特開平２
−７２３１６号公報、特開平３−２４９６１４号公報で
提案されている。しかしながら、これらのズームレンズ
系は前玉径及びレンズ全長が共に大型であり、コンパク
トカメラの撮影レンズとしては必ずしも十分でない。In addition to this, a zoom lens having a wide angle of view and a high zoom ratio, for example, has a half angle of view at the wide-angle end of about 38 ° and a zoom ratio of about 3.5 by combining multiple lenses. JP-A-2
-72316 and Japanese Patent Laid-Open No. 3-249614. However, these zoom lens systems have a large front lens diameter and a large overall lens length, and are not always sufficient as photographing lenses for compact cameras.

【０００９】特に外部ファインダーを使用するカメラに
適用する際は、広角端時にレンズ鏡筒がファインダーの
撮影視野を覆ってしまうという問題点がある。又この結
果、ファインダー配置やカメラの形態の制限を与えてし
まうという問題点も生じてくる。Particularly when applied to a camera using an external viewfinder, there is a problem that the lens barrel covers the field of view of the viewfinder at the wide-angle end. Further, as a result, there arises a problem that the viewfinder arrangement and the camera form are restricted.

【００１０】[0010]

【発明が解決しようとする課題】一般にズームレンズに
おいて各レンズ群の屈折力を強めれば所定の変倍比を得
るための各レンズ群の移動量が少なくなり、レンズ全長
の短縮化を図りつつ高変倍化が可能となる。しかしなが
ら単に各レンズ群の屈折力を強めると変倍に伴う収差変
動が大きくなり、特に高変倍化及び広画角化を図る際に
は全変倍範囲にわたり良好なる光学性能を得るのが難し
くなってくるという問題点がある。Generally, in a zoom lens, if the refractive power of each lens group is strengthened, the amount of movement of each lens group for obtaining a predetermined zoom ratio is reduced, and the total lens length is shortened. High zoom ratio is possible. However, if the refracting power of each lens unit is simply increased, the aberration variation due to zooming becomes large, and it is difficult to obtain good optical performance over the entire zooming range, especially when achieving high zooming and widening the angle of view. There is a problem that it will become.

【００１１】一方、非球面を用いて収差補正を容易にし
て高変倍化及びレンズ系全体の小型化を図る方法が種々
と提案されている。しかしながら非球面は球面収差やコ
マ収差等の補正には有効であるが色収差の補正効果は少
ない。このため高変倍のズームレンズでは変倍に伴う色
収差の変動を良好に補正するのが重要な課題となってい
る。On the other hand, various methods have been proposed in which an aspherical surface is used to facilitate aberration correction to achieve high zooming and downsizing of the entire lens system. However, the aspherical surface is effective in correcting spherical aberration and coma, but has little effect of correcting chromatic aberration. For this reason, it is an important issue for a zoom lens with a high zoom ratio to satisfactorily correct the variation of chromatic aberration due to zooming.

【００１２】本発明は、全体として４つのレンズ群より
構成し、各レンズ群のレンズ構成や変倍における各レン
ズ群の変倍分担等を適切に設定し、広角端の撮影画角が
７４°程度、変倍比３．５程度の全変倍範囲にわたり高
い光学性能を有したズームレンズの提供を目的とする。The present invention is composed of four lens groups as a whole, the lens configuration of each lens group, the variable power distribution of each lens group in variable power, etc. are appropriately set, and the photographing angle of view at the wide angle end is 74 °. The objective of the present invention is to provide a zoom lens having high optical performance over the entire zoom range with a zoom ratio of about 3.5.

【００１３】[0013]

【課題を解決するための手段】本発明のズームレンズ
は、 （１−１）物体側より順に広角端において単一又は複数
のレンズ群を有する全体として負の屈折力の第１群、正
の屈折力の第２群、単一又は複数のレンズ群を有する全
体として正の屈折力の第３群、そして負の屈折力の第４
群の４つのレンズ群を有し、各レンズ群を移動させて変
倍を行う際、第ｉ群（ｉ≧２）の広角端と望遠端の横倍
率を各々βｉＷ，βｉＴとし、第ｉ群の変倍率Δβｉを Δβｉ＝｜βｉＴ／βｉＷ｜ とおいたとき、該第２群は正の屈折力のレンズ群中、Δ
βｉ＞１なる条件で最も変倍率が大きく、且つ２枚の正
レンズ又は２枚の負レンズとそれらと逆の屈折力の１つ
のレンズとを接合した全体として正の屈折力の３枚貼合
わせレンズを有していることを特徴としている。The zoom lens of the present invention comprises (1-1) a first lens unit having a negative refracting power as a whole, which has a single lens unit or a plurality of lens units at the wide-angle end in order from the object side; A second group of refractive power, a third group of positive refractive power with a single or multiple lens groups, and a fourth group of negative refractive power.
When there are four lens groups, each lens group is moved to perform zooming, the lateral magnifications of the wide-angle end and the telephoto end of the i-th group (i ≧ 2) are βiW and βiT, respectively. When the scaling factor Δβi of Δβi is set to Δβi = | βiT / βiW |, the second group is
Under the condition of βi> 1, the largest zoom ratio is obtained, and two positive lenses or two negative lenses and one lens having the opposite refractive power are cemented together, and three pieces having a positive refractive power are bonded as a whole. It is characterized by having a lens.

【００１４】特に、広角端に対し、望遠端において該第
１群と第２群の間隔及び該第３群と第４群の間隔が小と
なり、該第２群と第３群の間隔が大となるように各レン
ズ群を光軸上移動させて変倍を行っていることを特徴と
している。In particular, the distance between the first and second groups and the distance between the third and fourth groups are small and the distance between the second and third groups is large at the telephoto end with respect to the wide-angle end. It is characterized in that each lens unit is moved on the optical axis so that the zooming is performed.

【００１５】（１−２）物体側より順に広角端において
単一又は複数のレンズ群を有する全体として負の屈折力
の第１群、正の屈折力の第２群、単一又は複数のレンズ
群を有する全体として正の屈折力の第３群、そして負の
屈折力の第４群の４つのレンズ群を有し、各レンズ群を
移動させて変倍を行う際、該第２群は２枚の正レンズ又
は２枚の負レンズとそれらと逆の屈折力の１つのレンズ
とを接合した全体として正の屈折力の３枚貼合わせレン
ズを有しており、該第２群よりも像面側に焦点距離をＦ
Ｂ（ＦＢ＜０）、広角端における全系の焦点距離をＦＷ
としたとき ｜ＦＢ／ＦＷ｜＜１．１ 成る条件を満足する負の屈折力のレンズ群が設けられて
いることを特徴としている。(1-2) A first group having negative refracting power, a second group having positive refracting power as a whole, and a single or plural lenses having a single or plural lens groups at the wide-angle end in order from the object side. There are four lens groups, namely, a third lens group having a positive refractive power and a fourth lens group having a negative refractive power as a whole, and each lens group is moved to perform zooming. It has a three-piece cemented lens having a positive refracting power as a whole in which two positive lenses or two negative lenses and one lens having a refracting power opposite to those are cemented, and more than the second group. The focal length is F on the image side
B (FB <0), the focal length of the entire system at the wide-angle end is FW
It is characterized in that a lens unit having a negative refractive power that satisfies the condition | FB / FW | <1.1 is provided.

【００１６】特に、広角端に対し、望遠端において該第
１群と第２群の間隔及び該第３群と第４群の間隔が小と
なり、該第２群と第３群の間隔が大となるように各レン
ズ群を光軸上移動させて変倍を行っていることを特徴と
している。In particular, the distance between the first and second groups and the distance between the third and fourth groups are small and the distance between the second and third groups is large at the telephoto end with respect to the wide-angle end. It is characterized in that each lens unit is moved on the optical axis so that the zooming is performed.

【００１７】[0017]

【実施例】図１〜図３は本発明のズームレンズの近軸屈
折力配置の説明図、図４〜図１０は各々本発明の数値実
施例１〜７の広角端におけるレンズ断面図である。図１
１〜図３１は本発明の数値実施例１〜７の諸収差図であ
る。1 to 3 are explanatory views of a paraxial refracting power arrangement of a zoom lens of the present invention, and FIGS. 4 to 10 are lens cross-sectional views at the wide angle end of Numerical Examples 1 to 7 of the present invention, respectively. . FIG.
1 to 31 are various aberration diagrams of Numerical Examples 1 to 7 of the present invention.

【００１８】図中、Ｌ１は負の屈折力の第１群、Ｌ２は
正の屈折力の第２群、Ｌ３は正の屈折力の第３群、Ｌ４
は負の屈折力の第４群である。矢印は広角側から望遠側
への変倍を行う際の各レンズ群の移動方向を示す。ＳＰ
は絞り、ＳＰＰは固定絞り、ＩＰは像面である。In the figure, L1 is a first group having a negative refractive power, L2 is a second group having a positive refractive power, L3 is a third group having a positive refractive power, and L4.
Is the fourth group of negative refractive power. The arrows indicate the direction of movement of each lens group when zooming from the wide-angle side to the telephoto side. SP
Is an aperture, SPP is a fixed aperture, and IP is an image plane.

【００１９】本実施例では広角端から望遠端への変倍に
際して、第１群と第２群の間隔及び第３群と第４群の間
隔が減少し、第２群と第３群の間隔が増大するように各
レンズ群を独立に光軸上物体側へ移動させている。In this embodiment, during zooming from the wide-angle end to the telephoto end, the distance between the first group and the second group and the distance between the third group and the fourth group decrease, and the distance between the second group and the third group decreases. Each lens group is independently moved to the object side on the optical axis so that

【００２０】一般にズームレンズにおいて変倍に伴い発
生する倍率色収差や球面収差等を補正する際、各レンズ
群を少ないレンズ枚数にて効果的な補正を行うことが望
ましい。しかしながら現実的な硝材の存在域を考慮した
とき大変困難である。又レンズ枚数を増加させて補正す
る方法では一定の周辺光量比を獲得するためにレンズど
うしの干渉を防止するようにレンズを配置しなければな
らず、この時所定のバックフォーカスを維持することが
困難となったり、又レンズ外径が大きくなりすぎてメカ
機構が難しくなってくる場合がある。Generally, when correcting magnification chromatic aberration, spherical aberration, etc., which occur with zooming in a zoom lens, it is desirable to effectively correct each lens group with a small number of lenses. However, it is very difficult when considering the existence area of a realistic glass material. Further, in the method of correcting by increasing the number of lenses, it is necessary to arrange the lenses so as to prevent interference between the lenses in order to obtain a constant peripheral light amount ratio, and at this time, it is possible to maintain a predetermined back focus. In some cases, it becomes difficult, or the outer diameter of the lens becomes too large, which makes the mechanical mechanism difficult.

【００２１】この為本発明ではズームレンズの基本構成
を物体側より順に負の屈折力の第１群、正の屈折力の第
２群、正の屈折力の第３群、そして負の屈折力の第４群
の４つのレンズ群より構成し、広角端に対し、望遠端に
おいて該第１群と第２群の間隔及び該第３群と第４群の
間隔が小となり、該第２群と第３群の間隔は大となるよ
うに各レンズ群を光軸上物体側へ移動させている。そし
て変倍中、レンズ系全体が略対称型に近くなるように
し、全変倍範囲にわたり良好なる光学性能を得ている。
特に広角側においてレンズ系全体がレトロフォーカス型
となるようにして広画角化を容易にしている。Therefore, in the present invention, the basic construction of the zoom lens is, in order from the object side, the first group having negative refracting power, the second group having positive refracting power, the third group having positive refracting power, and the negative refracting power. The fourth lens group of the fourth lens group, the distance between the first group and the second group and the distance between the third group and the fourth group are small at the telephoto end with respect to the wide-angle end, Each lens group is moved toward the object side on the optical axis so that the distance between the third lens group and the third lens group becomes large. Then, during zooming, the entire lens system is made to be substantially symmetrical, and good optical performance is obtained over the entire zoom range.
In particular, on the wide-angle side, the entire lens system is retrofocused to facilitate widening of the angle of view.

【００２２】図１は本発明の数値実施例１〜３の近軸的
屈折力配置図を示している。同図では第１群Ｌ１群を物
体側より正の屈折力の第Ｌ１１群と負の屈折力の第Ｌ１
２群の２つのレンズ群より構成している。そして広角端
より望遠端への変倍に際して第１群〜第４群を前述の如
く移動させると共に第Ｌ１１群と第Ｌ１２群の間隔を大
きくすることにより広角端では負の歪曲収差の補正を良
好に行い、望遠端ではテレフォトタイプのレンズ構成と
して光学性能の向上を図っている。FIG. 1 shows a paraxial refractive power arrangement of Numerical Embodiments 1 to 3 of the present invention. In the figure, the first lens unit L1 is arranged from the object side to the L11th lens unit having a positive refractive power and the L1th lens unit having a negative refractive power.
It is composed of two lens groups of two groups. At the time of zooming from the wide-angle end to the telephoto end, the first to fourth groups are moved as described above, and the distance between the L11th and L12th groups is increased, so that negative distortion is well corrected at the wide-angle end. At the telephoto end, a telephoto type lens configuration is used to improve the optical performance.

【００２３】図２は本発明の数値実施例４，５の近軸的
屈折力配置図を示している。同図では第１群〜第４群の
各レンズ群を前述した如く移動させている。特に変倍中
におけるレンズ系が全体として対称型を維持するように
して良好な光学性能を得ると共に広角端におけるレンズ
全長の短縮化を図っている。FIG. 2 shows a paraxial refractive power arrangement diagram of Numerical Embodiments 4 and 5 of the present invention. In the figure, the first to fourth lens groups are moved as described above. In particular, the lens system during zooming maintains a symmetrical type as a whole to obtain good optical performance and to shorten the total lens length at the wide-angle end.

【００２４】図３は本発明の数値実施例６，７の近軸的
屈折力配置図を示している。同図では第１群Ｌ１を正の
屈折力の第Ｌ１１群と負の屈折力の第Ｌ１２群より構成
し、第３群Ｌ３を負の屈折力の第Ｌ３１群と正の屈折力
の第Ｌ３２群より構成している。そして広角端から望遠
端への変倍に際して第１群〜第４群を前述の如く移動さ
せると共に第Ｌ１１群と第Ｌ１２群の間隔が大きくな
り、第Ｌ３１群と第Ｌ３２群の間隔が大きくなるように
各々物体側へ移動させている。これにより特に軸外光線
が第Ｌ３２群の光軸より離れた位置を通過するようにし
て軸上収差と軸外収差の補正をバランス良く行ってい
る。FIG. 3 shows a paraxial refractive power arrangement of Numerical Embodiments 6 and 7 of the present invention. In the figure, the first lens unit L1 is composed of an L11 lens unit having a positive refractive power and an L12 lens unit having a negative refractive power, and a third lens unit L3 is composed of an L31 lens unit having a negative refractive power and an L32 lens unit having a positive refractive power. It is composed of groups. When zooming from the wide-angle end to the telephoto end, the first to fourth groups are moved as described above, the distance between the L11 and L12 groups is increased, and the distance between the L31 and L32 groups is increased. Each of them is moved to the object side. As a result, the off-axis ray is allowed to pass through a position distant from the optical axis of the L32 group, and the axial aberration and the off-axis aberration are corrected in a well-balanced manner.

【００２５】そして本発明では次の構成要件（イ），
（ロ）のうち少なくとも何れか一方の構成をとることに
より高変倍化を図る際の変倍に伴う色収差の変動を良好
に補正し、全変倍範囲にわたり高い光学性能を得てい
る。In the present invention, the following constituent requirements (a),
By adopting at least one of the constitutions of (b), the variation of chromatic aberration due to the magnification change at the time of achieving the high magnification change is favorably corrected, and high optical performance is obtained over the entire range of magnification change.

【００２６】（イ）第ｉ群（ｉ≧２）の広角端と望遠端
の横倍率を各々βｉＷ，βｉＴとし、第ｉ群の変倍率Δ
βｉを Δβｉ＝｜βｉＴ／βｉＷ｜ とおいたとき、第２群が正の屈折力のレンズ群中、Δβ
ｉ＞１なる条件で最も変倍率が大きく、且つ２枚の正レ
ンズ又は２枚の負レンズとそれらと逆の屈折力の１つの
レンズとを接合した全体として正の屈折力の３枚貼合わ
せレンズ（レンズＡ）を有すること。(A) The lateral magnifications at the wide-angle end and the telephoto end of the i-th group (i ≧ 2) are βiW and βiT, respectively, and the magnification ratio Δ of the i-th group is Δ.
When βi is set as Δβi = | βiT / βiW |, when the second lens group has a positive refractive power, Δβ
If the condition of i> 1 is satisfied, the maximum zoom ratio is large, and two positive lenses or two negative lenses and one lens having the opposite refractive power are cemented together, and three pieces having a positive refractive power are bonded as a whole. Must have a lens (lens A).

【００２７】（ロ）第２群が２枚の正レンズ又は２枚の
負レンズとそれらと逆の屈折力の１つのレンズとを接合
した全体として正の屈折力の３枚貼合わせレンズ（レン
ズＡ）を有しており、第２群よりも像面側に焦点距離を
ＦＢ（ＦＢ＜０）、広角端における全系の焦点距離をＦ
Ｗとしたとき ｜ＦＢ／ＦＷ｜＜１．１ ‥‥‥（１） 成る条件を満足する負の屈折力のレンズ群Ｂを設けるこ
と。(B) The second lens group has two positive lenses or two negative lenses and one lens having the opposite refractive power cemented with each other, and has a positive refractive power as a whole. A), the focal length is FB (FB <0) closer to the image surface than the second lens unit, and the focal length of the entire system is F at the wide-angle end.
When W is set: | FB / FW | <1.1 (1) Provide a lens unit B having a negative refractive power that satisfies the following condition.

【００２８】ここで条件式（１）はレンズ系全体の小型
化を効率よく達成する為のものである。この条件式を外
れるとレンズＡを含んだ第２群より像面側に位置する負
の屈折力のレンズ群の変倍に伴う移動量に対する変倍作
用が弱まってくる。又広角端においてレトロタイプの作
用が弱まってくる為レンズ系全体が大型化してくるので
良くない。The conditional expression (1) is for efficiently achieving the downsizing of the entire lens system. If this conditional expression is not satisfied, the zooming effect on the amount of movement of the lens unit having negative refractive power located closer to the image plane than the second lens unit including the lens A due to zooming becomes weak. Moreover, since the action of the retro type is weakened at the wide-angle end, the entire lens system becomes large, which is not good.

【００２９】次に第２群に設けたレンズＡの特徴につい
て説明する。図３２，図３３，図３４は後述する本発明
の数値実施例５における物体距離が無限遠での変倍域中
の各々３次の軸上色収差、倍率色収差、球面収差を示
し、ズームレンズ系中の各レンズ群での発生量とそのト
ータル量を表した説明図である。Next, the features of the lens A provided in the second group will be described. 32, 33, and 34 respectively show third-order axial chromatic aberration, lateral chromatic aberration, and spherical aberration in the zooming range when the object distance is infinity in Numerical Example 5 of the present invention, which will be described later. It is explanatory drawing showing the generation | occurrence | production amount in each lens group in the inside, and the total amount.

【００３０】ここで正の屈折力の第２群（Ｌ２）に着目
すると負の屈折力の第１群（Ｌ１）で発生する軸上色収
差、倍率色収差及び負の屈折力の第４群（Ｌ４）にて発
生する倍率色収差と球面収差をキャンセルしていること
が理解される。Focusing on the second lens unit (L2) having a positive refractive power, the axial chromatic aberration, the chromatic aberration of magnification, and the fourth lens unit (L4) having a negative refractive power generated in the first lens unit (L1) having a negative refractive power. It is understood that the chromatic aberration of magnification and the spherical aberration that occur in () are canceled.

【００３１】ここで第２群（Ｌ２）中に前述した構成の
レンズＡを導入することにより、該レンズＡ中の２つの
接合レンズ面にて色収差と球面収差をお互い良好に補正
している。この場合物体側及び像面側の何れの接合レン
ズ面も負の屈折力を有するように配置することが望まし
く、それによれば第２群（Ｌ２）にて発生する色収差と
球面収差をズームレンズ系全体においてバランス良く補
正することができる。By introducing the lens A having the above-mentioned configuration into the second lens unit (L2), the chromatic aberration and the spherical aberration are favorably corrected at the two cemented lens surfaces in the lens A. In this case, it is desirable that both the cemented lens surface on the object side and the cemented lens surface on the image surface side have a negative refracting power, whereby chromatic aberration and spherical aberration generated in the second lens unit (L2) can be reduced. It is possible to make a well-balanced correction as a whole.

【００３２】尚本実施例においてレンズＡの接合レンズ
面を分離し、レンズ面間に空気間隔を置くと高次の球面
収差が多く発生し、これを他のレンズ面にてこれを補正
することが困難になってくる。又接合レンズ面を一つと
した場合は、色収差と球面収差をバランス良く補正する
のが難しくなってくる。In this embodiment, if the cemented lens surface of the lens A is separated and an air space is provided between the lens surfaces, a lot of high-order spherical aberrations occur, and this should be corrected by another lens surface. Becomes difficult. If only one cemented lens surface is used, it becomes difficult to correct chromatic aberration and spherical aberration in a well-balanced manner.

【００３３】本発明の目的とするズームレンズは以上の
諸条件を満足することにより達成されるが、更にレンズ
系全体の小型化を図りつつ全変倍範囲にわたり高い光学
性能を得るには前述した構成要件（イ）又は（ロ）の基
で以下の諸条件のうち少なくとも１つを満足させるのが
良い。The zoom lens which is the object of the present invention can be achieved by satisfying the above-mentioned various conditions. To attain high optical performance over the entire zoom range while further downsizing the entire lens system, the zoom lens described above is provided. It is preferable that at least one of the following conditions is satisfied based on the constituent requirement (a) or (b).

【００３４】（２−１）変倍領域において最も大きな変
倍率を有する負の屈折力のレンズ群Ｃの焦点距離をＦ
Ｃ、広角端における全系の焦点距離をＦＷとしたとき ０．５＜｜ＦＣ／ＦＷ｜＜１．２ ‥‥‥（２） なる条件を満足することである。(2-1) The focal length of the lens unit C having a negative refractive power and having the largest zoom ratio in the zoom region is F
C, when the focal length of the entire system at the wide-angle end is FW, the condition of 0.5 <| FC / FW | <1.2 (2) is satisfied.

【００３５】ここでレンズ群Ｃは図１，図２では第４
群、図３では第Ｌ３１群又は第４群に相当する。条件式
（２）の上限値を越えてレンズ群Ｃの屈折力が弱くなっ
てくると一定の変倍比を得る為にレンズ群Ｃの移動量を
増大させねばならず、この結果、レンズ全長が増大して
くるので良くない。又下限値を越えて、レンズ群Ｃの屈
折力が強くなりすぎるとコマ収差及び像面湾曲収差等の
軸外収差の発生量が多くなりこれを良好に補正すること
が困難になってくる。Here, the lens group C is the fourth lens in FIGS.
This group corresponds to the L31 group or the fourth group in FIG. When the upper limit of conditional expression (2) is exceeded and the refractive power of the lens group C becomes weaker, the amount of movement of the lens group C must be increased in order to obtain a constant zoom ratio, and as a result, the total lens length is increased. Is increasing, which is not good. If the lower limit value is exceeded and the refractive power of the lens group C becomes too strong, the amount of off-axis aberrations such as coma and field curvature aberration increases, and it becomes difficult to correct these aberrations satisfactorily.

【００３６】（２−２）レンズＡは物体側より順に物体
側に凸面を向けたメニスカス状の負レンズＡ１、両レン
ズ面が凸面の正レンズＡ２、像面側に凸面を向けたメニ
スカス状の負レンズＡ３より構成することである。今負
レンズＡ１と正レンズＡ２の接合レンズ面をＳ１、正レ
ンズＡ２と負レンズＡ３の接合レンズ面をＳ２とする。
接合レンズ面Ｓ１にて強い色収差の補正作用をもたらす
為には接合レンズ面Ｓ１を強い曲率にして接合レンズ面
の屈折力を強めるのが有効である。しかしながら単に曲
率を強めると接合レンズ面Ｓ１上の軸上光線の光軸付近
を通過する光線に対し、周辺を通過する光線が屈折作用
を及ぼしてしまい、高次の球面収差が発生してくる。(2-2) The lens A is a meniscus negative lens A1 having a convex surface directed from the object side to the object side, a positive lens A2 having convex lens surfaces on both sides, and a meniscus shape having a convex surface directed to the image side. It is to be composed of a negative lens A3. Now, the cemented lens surface of the negative lens A1 and the positive lens A2 is S1, and the cemented lens surface of the positive lens A2 and the negative lens A3 is S2.
In order to bring about a strong chromatic aberration correcting action on the cemented lens surface S1, it is effective to make the cemented lens surface S1 have a strong curvature to strengthen the refractive power of the cemented lens surface. However, if the curvature is simply increased, the rays passing through the periphery of the axial rays on the cemented lens surface S1 have a refracting effect on the rays passing near the optical axis, and high-order spherical aberration occurs.

【００３７】そこで本発明では接合レンズ面Ｓ１と接合
レンズ面Ｓ２の２つの接合レンズ面を設けている。これ
によりレンズＡ中に色収差の補正作用を有するレンズ面
を増し、又それと同時に球面収差を色収差と共にバラン
ス良く補正している。Therefore, in the present invention, two cemented lens surfaces, that is, a cemented lens surface S1 and a cemented lens surface S2 are provided. As a result, the lens surface having the effect of correcting chromatic aberration is increased in the lens A, and at the same time, spherical aberration is corrected in good balance with chromatic aberration.

【００３８】（２−３）第２群よりも像面側に絞りを配
置することである。本発明のズームレンズでは軸外光線
が第４群に対して光軸と対称に近い位置でレンズ内を通
過する。この為本発明では前述の如く絞りを配置し、こ
れにより第４群で発生する軸外の諸収差を良好に補正し
ている。(2-3) Arranging the stop closer to the image side than the second lens unit. In the zoom lens of the present invention, the off-axis light ray passes through the lens at a position close to the optical axis with respect to the fourth lens group. Therefore, in the present invention, the stop is arranged as described above, and thereby various off-axis aberrations occurring in the fourth lens group are corrected well.

【００３９】（２−４）前記第１群と第２群の広角端に
おける合成焦点距離をＦ１，２Ｗ、広角端における全系
の焦点距離をＦＷとしたとき ０．８＜Ｆ１，２Ｗ／ＦＷ＜１．７ ‥‥‥（３） なる条件を満足することである。(2-4) When the combined focal length of the first group and the second group at the wide-angle end is F1, 2W, and the focal length of the entire system at the wide-angle end is FW, 0.8 <F1,2W / FW <1.7 ... (3) It is to satisfy the following condition.

【００４０】条件式（３）はレンズ系全体を小型にしつ
つズーム全域にわたって光学性能を良好に保つ為のもの
である。条件式（３）の上限値を越えると広角端におい
て一定の焦点距離を得る場合、他の負レンズ群の屈折力
を弱める必要がある。この結果一定の変倍比を得る為の
第４群と他のレンズ群の変倍に伴う移動量が増加し、又
レンズ群どうしの干渉を防止する為にレンズ群間隔を予
め広くとらねばならなくなり、レンズ全長が増加してく
るので良くない。Conditional expression (3) is for keeping the optical performance good over the entire zoom range while making the entire lens system compact. When the upper limit of conditional expression (3) is exceeded, it is necessary to weaken the refractive power of the other negative lens group in order to obtain a fixed focal length at the wide-angle end. As a result, the amount of movement of the fourth lens unit for obtaining a constant zoom ratio and other lens units increases with zooming, and the lens group spacing must be widened in advance in order to prevent interference between lens groups. It is not good because it disappears and the total lens length increases.

【００４１】他方、下限値を越えて第１群と第２群の合
成焦点距離Ｆ１，２Ｗが短くなってくると所定のバック
フォーカスを得ることが難しくなると同時に負の球面収
差が多く発生し、これを良好に補正することが困難にな
ってくる。On the other hand, if the combined focal lengths F1 and W of the first and second lens units become shorter than the lower limit, it becomes difficult to obtain a predetermined back focus, and at the same time a large amount of negative spherical aberration occurs. It becomes difficult to satisfactorily correct this.

【００４２】（２−５）前記３枚貼合わせレンズの物体
側からｉ番目のレンズの材質のアッベ数をνＡｉ、ｉ番
目のレンズ面の曲率半径をＲＡｉ、該３枚貼合わせレン
ズの焦点距離をＦＡとしたとき ０．６＜ＦＡ／ＦＷ＜１．３ ‥‥‥（４） ２０＜νＡ２−（νＡ１＋νＡ３）／２ ‥‥‥（５） ０．１３＜（ＲＡ３＋ＲＡ２）／（ＲＡ３−ＲＡ２）＜０．４５ ‥‥‥（６） なる条件を満足することである。(2-5) The Abbe number of the material of the i-th lens from the object side of the three-piece cemented lens is νAi, the radius of curvature of the i-th lens surface is RAi, and the focal length of the three-piece cemented lens is Where FA is 0.6 <FA / FW <1.3 (4) 20 <νA2- (νA1 + νA3) / 2 (5) 0.13 <(RA3 + RA2) / (RA3-RA2) <0.45 (6) It is to satisfy the condition.

【００４３】条件式（４）は広角端における第２群の屈
折力とレンズ系全体の屈折力との比に関する。条件式
（４）の上限値を越えて第２群の屈折力が弱くなりすぎ
ると一定の変倍比を得る為の第２群の移動量が増大し、
結果としてレンズ全長が増大してくる。一方、下限値を
越えて第２群の屈折力が強くなってくると高次の球面収
差及びコマ収差が多く発生し、これらの良好なる補正が
困難になってくる。Conditional expression (4) relates to the ratio between the refractive power of the second lens unit at the wide-angle end and the refractive power of the entire lens system. When the upper limit of conditional expression (4) is exceeded and the refractive power of the second lens unit becomes too weak, the amount of movement of the second lens unit to obtain a constant zoom ratio increases,
As a result, the total lens length increases. On the other hand, when the refractive power of the second lens group becomes stronger beyond the lower limit, a lot of high-order spherical aberration and coma occur, and it becomes difficult to correct them satisfactorily.

【００４４】条件式（５）は３枚貼合わせレンズ（レン
ズＡ）で第４群より発生する色収差を効果的に補正する
為の条件式である。この条件式（５）を外れると変倍域
全域にわたって良好な色収差の補正が難しくなってく
る。Conditional expression (5) is a conditional expression for effectively correcting the chromatic aberration generated from the fourth lens group in the three-piece cemented lens (lens A). If the conditional expression (5) is not satisfied, it becomes difficult to satisfactorily correct chromatic aberration over the entire zoom range.

【００４５】条件式（６）はレンズＡ中の両レンズ面が
凸面のレンズＡ２の形状因子に関し、条件式（６）の範
囲を超えると接合レンズ面における球面収差と色収差を
バランス良く補正するのが難しくなり変倍域全域にわた
って高画質な光学系を達成するのが難しくなってくる。Conditional expression (6) relates to the shape factor of the lens A2 in which both lens surfaces in the lens A are convex surfaces. If the range of conditional expression (6) is exceeded, spherical aberration and chromatic aberration on the cemented lens surface will be corrected in a well-balanced manner. It becomes difficult to achieve a high quality optical system over the entire zoom range.

【００４６】（２−６）第２群を２枚の正レンズ又は２
枚の負レンズとそれらと逆の屈折力の１つのレンズとを
接合した全体として正の屈折力の３枚貼合わせレンズよ
り構成することである。これによればレンズ全長の短縮
化と同時に入射瞳位置を物体側に持っていけて、前玉径
の小型化が行える。(2-6) The second lens unit is composed of two positive lenses or two.
It is to be composed of three cemented lenses each having a positive refracting power as a whole in which a negative lens and one lens having a refracting power opposite thereto are cemented. According to this, the entrance pupil position can be brought to the object side at the same time as the total lens length is shortened, and the front lens diameter can be reduced.

【００４７】（２−７）各々レンズ群に非球面を導入す
ることが良い。これによれば光学性能を、より向上させ
ることができる。(2-7) It is preferable to introduce an aspherical surface into each lens group. According to this, the optical performance can be further improved.

【００４８】（２−８）ズーミング中のレンズ群移動に
関し、２つ以上のレンズ群を一体として移動させる方式
をとっても良い。これによれば鏡胴機構の簡略化を行う
際に有効となる。(2-8) Regarding the movement of the lens groups during zooming, a method of moving two or more lens groups as a unit may be adopted. This is effective in simplifying the lens barrel mechanism.

【００４９】（２−９）レンズ系が絞りを持つ際は、変
倍時に該絞りを他のレンズ群とは独立に移動させても良
く、又他のレンズ群と一体に移動させても良い。それに
より変倍時に移動する入射瞳位置近傍に絞り位置を配置
することが可能となり、小絞り時の像面湾曲収差の変化
を良好に防止するのが有利になる。(2-9) When the lens system has a diaphragm, the diaphragm may be moved independently of the other lens groups during zooming, or may be moved integrally with the other lens groups. . This makes it possible to dispose the diaphragm position in the vicinity of the position of the entrance pupil that moves during zooming, and it is advantageous to favorably prevent changes in field curvature aberration when the diaphragm is small.

【００５０】（２−１０）本発明においてフォーカシン
グはズーミング中、フォーカス群の横倍率が等倍になら
ない任意のレンズ群が適用できる。第１群がある程度強
い屈折力を有している際は第１群を物体側へ移動するフ
ォーカス方式がズーム全域中任意の物体距離におけるフ
ォーカシング量を一定にでき、機構が簡略化されるので
好ましい。(2-10) In the present invention, focusing is applicable to any lens group in which the lateral magnification of the focus group does not become equal during zooming. When the first lens unit has a certain degree of strong refractive power, a focus method of moving the first lens unit to the object side is preferable because the focusing amount can be made constant at any object distance throughout the zoom range and the mechanism is simplified. .

【００５１】広角端においてバックフォーカスが充分に
あり、且つ最終レンズ群の屈折力がある程度強い場合は
最終レンズ群を像面側に移動するフォーカス方式が良
く、この際は第１群のレンズ外径の小型化を行うのに有
効となる。又第１群から最終レンズ群中の２つ以上のレ
ンズ群を同時に移動させるフォーカス方式でも良い。尚
フォーカス群が絞りを含む場合、絞りを光軸上固定状態
にしてフォーカス群を移動させるフォーカス方法はフォ
ーカス時に絞り機構を移動させる為の駆動トルクの低減
を行うことができる。When the back focus is sufficient at the wide-angle end and the refracting power of the final lens group is strong to some extent, a focusing method in which the final lens group is moved to the image side is preferable. It is effective for downsizing. Further, a focus system in which two or more lens groups in the first lens group to the last lens group are moved simultaneously may be used. When the focus group includes an aperture, the focus method of moving the focus group with the aperture fixed on the optical axis can reduce the driving torque for moving the aperture mechanism during focusing.

【００５２】（２−１１）第２群中の３枚貼合わせレン
ズ（レンズＡ）を物体側より順に物体側に凸面を向けた
正レンズ、両レンズ面が凹面の負レンズ、そして像面側
に凸面を向けた正レンズを接合して構成しても良い。(2-11) A three-lens cemented lens (lens A) in the second group is a positive lens whose convex surface faces the object side in order from the object side, a negative lens whose both lens surfaces are concave surfaces, and an image surface side. It may be configured by cementing a positive lens with the convex surface facing to.

【００５３】（２−１２）本発明において第Ｌ１群は単
一の正レンズより成る第Ｌ１１群、そして負レンズと正
レンズの２つのレンズ又は単一の負レンズより成る第Ｌ
１２群の２つのレンズ群より構成、又は正レンズ，負レ
ンズそして正レンズの３つのレンズより成る１つのレン
ズ群より構成するのが良い。(2-12) In the present invention, the L1-th lens unit is the L11-th lens unit consisting of a single positive lens, and the L1-Lth lens unit consisting of two lenses, a negative lens and a positive lens, or a single negative lens.
It is preferable that the lens group is composed of two lens groups of twelve groups, or one lens group composed of three lenses of a positive lens, a negative lens and a positive lens.

【００５４】第Ｌ２群は、物体側に凸面を向けた正レン
ズと両レンズ面が凸面の正レンズそして像面側に凸面を
向けたメニスカス状の負レンズの３つのレンズを接合し
た全体として正の屈折力の３枚貼合わせレンズより構成
するのが良い。The L2 lens group is composed of a positive lens having a convex surface directed toward the object side, a positive lens having convex lens surfaces on both sides, and a meniscus negative lens having a convex surface directed toward the image side. It is preferable to use a cemented three-lens lens having the above refractive power.

【００５５】第３群は負レンズ、負レンズと正レンズを
接合した貼合わせレンズの全体として３つのレンズより
構成、又は負レンズと正レンズ２つのレンズより構成す
るのが良い。The third lens group is preferably composed of three lenses as a negative lens or a cemented lens in which a negative lens and a positive lens are cemented, or a negative lens and a positive lens.

【００５６】第４群は像面側に凸面を向けたメニスカス
状の正レンズと少なくとも１つの負レンズより構成又は
物体側に凹面を向けた負レンズ、正レンズそして負レン
ズの３つのレンズより構成するのが良い。The fourth group is composed of a meniscus-shaped positive lens having a convex surface facing the image side and at least one negative lens, or a negative lens having a concave surface facing the object side, a positive lens and a negative lens. Good to do.

【００５７】次に本発明の数値実施例を示す。数値実施
例においてＲｉは物体側より順に第ｉ番目のレンズ面の
曲率半径、Ｄｉは物体側より第ｉ番目のレンズ厚及び空
気間隔、Ｎｉとνｉは各々物体側より順に第ｉ番目のレ
ンズのガラスの屈折率とアッベ数である。又前述の各条
件式と数値実施例における諸数値との関係を表−１に示
す。非球面形状は光軸方向にＸ軸、光軸と垂直方向にＨ
軸、光の進行方向を正としＲを近軸曲率半径、Ｋ，Ａ，
Ｂ，Ｃ，Ｄを各々非球面係数としたときNext, numerical examples of the present invention will be shown. In the numerical examples, Ri is the radius of curvature of the i-th lens surface in order from the object side, Di is the i-th lens thickness and air gap from the object side, and Ni and νi are respectively from the object side of the i-th lens. The refractive index of glass and the Abbe number. Table 1 shows the relationship between the above-mentioned conditional expressions and various numerical values in the numerical examples. The aspherical shape has an X axis along the optical axis and H along the direction perpendicular to the optical axis.
Axis, light traveling direction is positive, R is paraxial radius of curvature, K, A,
When B, C and D are aspherical coefficients respectively

【００５８】[0058]

【数１】 なる式で表わしている。又「ｅ−０ｘ」は１０^-xを意味
している。[Equation 1] It is expressed by "E-0x" means 10- ^x .

【００５９】〈数値実施例１〉 f= 28.84 〜101.06 fno=4.33 〜9.00 2ω= 73.8°〜24.2° R 1= 89.26 D 1= 3.30 N 1=1.51633 ν 1= 64.2 R 2= -73.65 D 2= 可変 R 3= -43.75 D 3= 1.20 N 2=1.80400 ν 2= 46.6 R 4= 18.20 D 4= 1.66 R 5= 21.94 D 5= 3.00 N 3=1.84665 ν 3= 23.8 R 6= 101.94 D 6= 可変 R 7= 16.54 D 7= 0.90 N 4=1.84665 ν 4= 23.8 R 8= 11.47 D 8= 4.80 N 5=1.48749 ν 5= 70.2 R 9= -22.49 D 9= 1.10 N 6=1.84665 ν 6= 23.8 R10= -25.48 D10= 0.80 R11= 絞り D11= 1.50 R12= -24.98 D12= 1.60 N 7=1.80518 ν 7= 25.4 R13= -47.12 D13= 1.60 R14= -35.21 D14= 1.90 N 8=1.65159 ν 8= 58.5 R15= -88.13 D15= 3.50 N 9=1.77249 ν 9= 49.6 R16= -15.90 D16= 可変 R17= -28.58 D17= 2.10 N10=1.84665 ν10= 23.8 R18= -19.52 D18= 3.33 R19= -17.07 D19= 1.80 N11=1.80400 ν11= 46.6 R20= 93.48 Numerical Example 1 f = 28.84 to 101.06 fno = 4.33 to 9.00 2ω = 73.8 ° to 24.2 ° R 1 = 89.26 D 1 = 3.30 N 1 = 1.51633 ν 1 = 64.2 R 2 = -73.65 D 2 = Variable R 3 = -43.75 D 3 = 1.20 N 2 = 1.80400 ν 2 = 46.6 R 4 = 18.20 D 4 = 1.66 R 5 = 21.94 D 5 = 3.00 N 3 = 1.84665 ν 3 = 23.8 R 6 = 101.94 D 6 = variable R 7 = 16.54 D 7 = 0.90 N 4 = 1.84665 ν 4 = 23.8 R 8 = 11.47 D 8 = 4.80 N 5 = 1.48749 ν 5 = 70.2 R 9 = -22.49 D 9 = 1.10 N 6 = 1.84665 ν 6 = 23.8 R10 = -25.48 D10 = 0.80 R11 = Aperture D11 = 1.50 R12 = -24.98 D12 = 1.60 N 7 = 1.80518 ν 7 = 25.4 R13 = -47.12 D13 = 1.60 R14 = -35.21 D14 = 1.90 N 8 = 1.65159 ν 8 = 58.5 R15 = -88.13 D15 = 3.50 N 9 = 1.77249 ν 9 = 49.6 R16 = -15.90 D16 = Variable R17 = -28.58 D17 = 2.10 N10 = 1.84665 ν10 = 23.8 R18 = -19.52 D18 = 3.33 R19 = -17.07 D19 = 1.80 N11 = 1.80400 ν11 = 46.6 R20 = 93.48

【００６０】[0060]

【表１】 〈数値実施例２〉 f= 28.74 〜101.17 fno=4.33 〜9.00 2ω= 74.0°〜24.1° R 1= 639.62 D 1= 2.50 N 1=1.51633 ν 1= 64.2 R 2= -56.09 D 2= 可変 R 3= -41.05 D 3= 1.20 N 2=1.80400 ν 2= 46.6 R 4= 19.48 D 4= 1.64 R 5= 23.15 D 5= 2.75 N 3=1.84665 ν 3= 23.8 R 6= 160.15 D 6= 可変 R 7= 15.90 D 7= 0.90 N 4=1.84665 ν 4= 23.8 R 8= 11.73 D 8= 4.80 N 5=1.48749 ν 5= 70.2 R 9= -21.42 D 9= 0.90 N 6=1.84665 ν 6= 23.8 R10= -28.84 D10= 可変 R11= 絞り D11= 1.50 R12= -27.14 D12= 1.60 N 7=1.80518 ν 7= 25.4 R13= -48.22 D13= 1.36 R14= -38.16 D14= 2.00 N 8=1.65159 ν 8= 58.5 R15= -26.71 D15= 3.50 N 9=1.77249 ν 9= 49.6 R16= -15.71 D16= 可変 R17= -34.31 D17= 2.30 N10=1.84665 ν10= 23.8 R18= -21.84 D18= 0.91 R19= -32.78 D19= 1.30 N11=1.69679 ν11= 55.5 R20= -58.16 D20= 3.21 R21= -18.28 D21= 1.50 N12=1.77249 ν12= 49.6 R22= 223.19 [Table 1] <Numerical Example 2> f = 28.74 to 101.17 fno = 4.33 to 9.00 2 ω = 74.0 ° to 24.1 ° R 1 = 639.62 D 1 = 2.50 N 1 = 1.51633 ν 1 = 64.2 R 2 = -56.09 D 2 = variable R 3 = -41.05 D 3 = 1.20 N 2 = 1.80400 ν 2 = 46.6 R 4 = 19.48 D 4 = 1.64 R 5 = 23.15 D 5 = 2.75 N 3 = 1.84665 ν 3 = 23.8 R 6 = 160.15 D 6 = Variable R 7 = 15.90 D 7 = 0.90 N 4 = 1.84665 ν 4 = 23.8 R 8 = 11.73 D 8 = 4.80 N 5 = 1.48749 ν 5 = 70.2 R 9 = -21.42 D 9 = 0.90 N 6 = 1.84665 ν 6 = 23.8 R10 = -28.84 D10 = Variable R11 = Aperture D11 = 1.50 R12 = -27.14 D12 = 1.60 N 7 = 1.80518 ν 7 = 25.4 R13 = -48.22 D13 = 1.36 R14 = -38.16 D14 = 2.00 N 8 = 1.65159 ν 8 = 58.5 R15 = -26.71 D15 = 3.50 N 9 = 1.77249 ν 9 = 49.6 R16 = -15.71 D16 = Variable R17 = -34.31 D17 = 2.30 N10 = 1.84665 ν10 = 23.8 R18 = -21.84 D18 = 0.91 R19 = -32.78 D19 = 1.30 N11 = 1.69679 ν11 = 55.5 R20 = -58.16 D20 = 3.21 R21 = -18.28 D21 = 1.50 N12 = 1.77249 ν12 = 49.6 R22 = 223.19

【００６１】[0061]

【表２】 〈数値実施例３〉 f= 28.85 〜101.00 fno=3.30 〜9.00 2ω= 73.7°〜24.2° R 1= 424.11 D 1= 2.40 N 1=1.51633 ν 1= 64.2 R 2= -60.06 D 2= 可変 R 3= -38.54 D 3= 1.20 N 2=1.80400 ν 2= 46.6 R 4= 19.56 D 4= 1.35 R 5= 21.49 D 5= 2.90 N 3=1.84665 ν 3= 23.8 R 6= 176.01 D 6= 可変 R 7= 15.65 D 7= 0.90 N 4=1.84665 ν 4= 23.8 R 8= 11.27 D 8= 4.50 N 5=1.48749 ν 5= 70.2 R 9= -21.44 D 9= 0.90 N 6=1.84665 ν 6= 23.8 R10= -29.88 D10= 可変 R11= 絞り D11= 3.00 R12= -24.67 D12= 2.55 N 7=1.80518 ν 7= 25.4 R13= -47.29 D13= 0.50 R14= -36.54 D14= 1.00 N 8=1.65159 ν 8= 58.5 R15= 155.75 D15= 5.80 N 9=1.77249 ν 9= 49.6 R16= -14.23 D16= 可変 R17= -28.76 D17= 2.30 N10=1.84665 ν10= 23.8 R18= -20.20 D18= 0.30 R19= -25.76 D19= 1.30 N11=1.69679 ν11= 55.5 R20= -80.69 D20= 3.51 R21= -18.83 D21= 1.50 N12=1.77249 ν12= 49.6 R22= 431.90 [Table 2] <Numerical Example 3> f = 28.85 to 101.00 fno = 3.30 to 9.00 2 ω = 73.7 ° to 24.2 ° R 1 = 424.11 D 1 = 2.40 N 1 = 1.51633 ν 1 = 64.2 R 2 = -60.06 D 2 = variable R 3 = -38.54 D 3 = 1.20 N 2 = 1.80400 ν 2 = 46.6 R 4 = 19.56 D 4 = 1.35 R 5 = 21.49 D 5 = 2.90 N 3 = 1.84665 ν 3 = 23.8 R 6 = 176.01 D 6 = variable R 7 = 15.65 D 7 = 0.90 N 4 = 1.84665 ν 4 = 23.8 R 8 = 11.27 D 8 = 4.50 N 5 = 1.48749 ν 5 = 70.2 R 9 = -21.44 D 9 = 0.90 N 6 = 1.84665 ν 6 = 23.8 R10 = -29.88 D10 = Variable R11 = Aperture D11 = 3.00 R12 = -24.67 D12 = 2.55 N 7 = 1.80518 ν 7 = 25.4 R13 = -47.29 D13 = 0.50 R14 = -36.54 D14 = 1.00 N 8 = 1.65159 ν 8 = 58.5 R15 = 155.75 D15 = 5.80 N 9 = 1.77249 ν 9 = 49.6 R16 = -14.23 D16 = Variable R17 = -28.76 D17 = 2.30 N10 = 1.84665 ν10 = 23.8 R18 = -20.20 D18 = 0.30 R19 = -25.76 D19 = 1.30 N11 = 1.69679 ν 11 = 55.5 R20 = -80.69 D20 = 3.51 R21 = -18.83 D21 = 1.50 N12 = 1.77249 ν12 = 49.6 R22 = 431.90

【００６２】[0062]

【表３】 〈数値実施例４〉 f= 28.86 〜101.58 fno=3.06 〜9.00 2ω= 73.7°〜24.1° R 1= 101.89 D 1= 2.85 N 1=1.51633 ν 1= 64.2 R 2= -61.28 D 2= 0.84 R 3= -39.42 D 3= 1.20 N 2=1.80400 ν 2= 46.6 R 4= 17.90 D 4= 1.07 R 5= 19.60 D 5= 3.35 N 3=1.84665 ν 3= 23.8 R 6= 95.82 D 6= 可変 R 7= 16.21 D 7= 0.90 N 4=1.84665 ν 4= 23.8 R 8= 11.92 D 8= 4.80 N 5=1.48749 ν 5= 70.2 R 9= -19.85 D 9= 0.90 N 6=1.84665 ν 6= 23.8 R10= -27.78 D10= 可変 R11= 絞り D11= 3.50 R12= -26.05 D12= 2.42 N 7=1.80518 ν 7= 25.4 R13= -45.55 D13= 0.56 R14= -34.59 D14= 1.00 N 8=1.65159 ν 8= 58.5 R15= 310.25 D15= 5.80 N 9=1.77249 ν 9= 49.6 R16= -13.79 D16= 可変 R17= -28.83 D17= 2.30 N10=1.84665 ν10= 23.8 R18= -20.42 D18= 0.24 R19= -25.56 D19= 1.30 N11=1.69679 ν11= 55.5 R20=-131.56 D20= 3.53 R21= -20.55 D21= 1.50 N12=1.77249 ν12= 49.6 R22= 204.29 [Table 3] <Numerical Example 4> f = 28.86 to 101.58 fno = 3.06 to 9.00 2 ω = 73.7 ° to 24.1 ° R 1 = 101.89 D 1 = 2.85 N 1 = 1.51633 ν 1 = 64.2 R 2 = -61.28 D 2 = 0.84 R 3 = -39.42 D 3 = 1.20 N 2 = 1.80400 ν 2 = 46.6 R 4 = 17.90 D 4 = 1.07 R 5 = 19.60 D 5 = 3.35 N 3 = 1.84665 ν 3 = 23.8 R 6 = 95.82 D 6 = variable R 7 = 16.21 D 7 = 0.90 N 4 = 1.84665 ν 4 = 23.8 R 8 = 11.92 D 8 = 4.80 N 5 = 1.48749 ν 5 = 70.2 R 9 = -19.85 D 9 = 0.90 N 6 = 1.84665 ν 6 = 23.8 R10 = -27.78 D10 = Variable R11 = Aperture D11 = 3.50 R12 = -26.05 D12 = 2.42 N 7 = 1.80518 ν 7 = 25.4 R13 = -45.55 D13 = 0.56 R14 = -34.59 D14 = 1.00 N 8 = 1.65159 ν 8 = 58.5 R15 = 310.25 D15 = 5.80 N 9 = 1.77249 ν 9 = 49.6 R16 = -13.79 D16 = Variable R17 = -28.83 D17 = 2.30 N10 = 1.84665 ν10 = 23.8 R18 = -20.42 D18 = 0.24 R19 = -25.56 D19 = 1.30 N11 = 1.69679 ν 11 = 55.5 R20 = -131.56 D20 = 3.53 R21 = -20.55 D21 = 1.50 N12 = 1.77249 ν12 = 49.6 R22 = 204.29

【００６３】[0063]

【表４】 〈数値実施例５〉 f= 28.85 〜101.49 fno=3.29 〜9.00 2ω= 73.7°〜24.1° R 1= 163.89 D 1= 3.25 N 1=1.51633 ν 1= 64.2 R 2= -26.34 D 2= 1.20 N 2=1.80400 ν 2= 46.6 R 3= 16.98 D 3= 1.21 R 4= 18.93 D 4= 2.50 N 3=1.84665 ν 3= 23.8 R 5= 108.28 D 5= 可変 R 6= 16.38 D 6= 0.90 N 4=1.84665 ν 4= 23.8 R 7= 11.85 D 7= 4.60 N 5=1.48749 ν 5= 70.2 R 8= -19.38 D 8= 0.90 N 6=1.84665 ν 6= 23.8 R 9= -25.91 D 9= 可変 R10= 絞り D10= 2.00 R11= -24.61 D11= 2.07 N 7=1.80518 ν 7= 25.4 R12= -71.21 D12= 0.48 R13= -44.54 D13= 1.30 N 8=1.65159 ν 8= 58.5 R14=-317.49 D14= 5.00 N 9=1.77249 ν 9= 49.6 R15= -13.39 D15= 可変 R16= -33.60 D16= 2.30 N10=1.84665 ν10= 23.8 R17= -22.01 D17= 0.77 R18= -25.47 D18= 1.30 N11=1.69679 ν11= 55.5 R19=-654.85 D19= 4.11 R20= -18.51 D20= 1.50 N12=1.77249 ν12= 49.6 R21=-202.43 [Table 4] <Numerical Example 5> f = 28.85 to 101.49 fno = 3.29 to 9.00 2 ω = 73.7 ° to 24.1 ° R 1 = 163.89 D 1 = 3.25 N 1 = 1.51633 ν 1 = 64.2 R 2 = -26.34 D 2 = 1.20 N 2 = 1.80400 ν 2 = 46.6 R 3 = 16.98 D 3 = 1.21 R 4 = 18.93 D 4 = 2.50 N 3 = 1.84665 ν 3 = 23.8 R 5 = 108.28 D 5 = Variable R 6 = 16.38 D 6 = 0.90 N 4 = 1.84665 ν 4 = 23.8 R 7 = 11.85 D 7 = 4.60 N 5 = 1.48749 ν 5 = 70.2 R 8 = -19.38 D 8 = 0.90 N 6 = 1.84665 ν 6 = 23.8 R 9 = -25.91 D 9 = Variable R10 = Aperture D10 = 2.00 R11 = -24.61 D11 = 2.07 N 7 = 1.80518 ν 7 = 25.4 R12 = -71.21 D12 = 0.48 R13 = -44.54 D13 = 1.30 N 8 = 1.65159 ν 8 = 58.5 R14 = -317.49 D14 = 5.00 N 9 = 1.77249 ν 9 = 49.6 R15 = -13.39 D15 = Variable R16 = -33.60 D16 = 2.30 N10 = 1.84665 ν10 = 23.8 R17 = -22.01 D17 = 0.77 R18 = -25.47 D18 = 1.30 N11 = 1.69679 ν11 = 55.5 R19 = -654.85 D19 = 4.11 R20 = -18.51 D20 = 1.50 N12 = 1.77249 ν12 = 49.6 R21 = -202.43

【００６４】[0064]

【表５】 〈数値実施例６〉 f= 28.83 〜101.02 fno=4.00 〜8.75 2ω= 73.8°〜24.2° R 1= 62.55 D 1= 2.40 N 1=1.84665 ν 1= 23.8 R 2=-704.82 D 2= 可変 R 3= -79.39 D 3= 1.20 N 2=1.77249 ν 2= 49.6 R 4= 27.29 D 4= 可変 R 5= 14.31 D 5= 0.90 N 3=1.84665 ν 3= 23.8 R 6= 13.95 D 6= 3.50 N 4=1.51822 ν 4= 59.0 R 7= -22.52 D 7= 0.90 N 5=1.84665 ν 5= 23.8 R 8= -40.19 D 8= 1.00 R 9= 絞り D 9= 4.67 R10= -17.92 D10= 2.85 N 6=1.80518 ν 6= 25.4 R11=-109.72 D11= 可変 R12= 264.84 D12= 1.10 N 7=1.84665 ν 7= 23.8 R13= 46.19 D13= 4.50 N 8=1.80439 ν 8= 39.6 R14= -15.33 D14= 可変 R15= -25.10 D15= 2.50 N 9=1.80518 ν 9= 25.4 R16= -17.84 D16= 1.21 R17= -17.91 D17= 1.30 N10=1.69679 ν10= 55.5 R18= -68.84 D18= 2.13 R19= -29.26 D19= 1.40 N11=1.77249 ν11= 49.6 R20=-308.12 [Table 5] <Numerical Example 6> f = 28.83 to 101.02 fno = 4.00 to 8.75 2ω = 73.8 ° to 24.2 ° R 1 = 62.55 D 1 = 2.40 N 1 = 1.84665 ν 1 = 23.8 R 2 = -704.82 D 2 = variable R 3 = -79.39 D 3 = 1.20 N 2 = 1.77249 ν 2 = 49.6 R 4 = 27.29 D 4 = Variable R 5 = 14.31 D 5 = 0.90 N 3 = 1.84665 ν 3 = 23.8 R 6 = 13.95 D 6 = 3.50 N 4 = 1.51822 ν 4 = 59.0 R 7 = -22.52 D 7 = 0.90 N 5 = 1.84665 ν 5 = 23.8 R 8 = -40.19 D 8 = 1.00 R 9 = aperture D 9 = 4.67 R10 = -17.92 D10 = 2.85 N 6 = 1.80518 ν 6 = 25.4 R11 = -109.72 D11 = variable R12 = 264.84 D12 = 1.10 N 7 = 1.84665 ν 7 = 23.8 R13 = 46.19 D13 = 4.50 N 8 = 1.80439 ν 8 = 39.6 R14 = -15.33 D14 = variable R15 = -25.10 D15 = 2.50 N 9 = 1.80518 ν 9 = 25.4 R16 = -17.84 D16 = 1.21 R17 = -17.91 D17 = 1.30 N10 = 1.69679 ν10 = 55.5 R18 = -68.84 D18 = 2.13 R19 = -29.26 D19 = 1.40 N11 = 1.77249 ν 11 = 49.6 R20 = -308.12

【００６５】[0065]

【表６】 〈数値実施例７〉 f= 28.87 〜100.85 fno=4.00 〜8.76 2ω= 73.7°〜24.2° R 1= 80.90 D 1= 2.40 N 1=1.84665 ν 1= 23.8 R 2=-245.18 D 2= 可変 R 3= -53.00 D 3= 1.20 N 2=1.69679 ν 2= 55.5 R 4= 23.65 D 4= 可変 R 5= 15.02 D 5= 1.20 N 3=1.84665 ν 3= 23.8 R 6= 15.55 D 6= 3.50 N 4=1.58913 ν 4= 61.2 R 7= -22.14 D 7= 1.00 N 5=1.84665 ν 5= 23.8 R 8= -51.78 D 8= 可変 R 9= 絞り D 9= 3.59 R10= -20.71 D10= 1.20 N 6=1.80518 ν 6= 25.4 R11= -86.49 D11= 可変 R12=固定絞り D12= 2.80 R13=3202.97 D13= 4.60 N 7=1.78589 ν 7= 44.2 R14= -15.18 D14= 可変 R15= -26.57 D15= 1.20 N 8=1.77249 ν 8= 49.6 R16= 74.12 D16= 2.20 N 9=1.80518 ν 9= 25.4 R17= 266.07 D17= 2.01 R18= -64.20 D18= 1.50 N10=1.69679 ν10= 55.5 R19=-13681.8 [Table 6] Numerical Example 7 f = 28.87 to 100.85 fno = 4.00 to 8.76 2 ω = 73.7 ° to 24.2 ° R 1 = 80.90 D 1 = 2.40 N 1 = 1.84665 ν 1 = 23.8 R 2 = -245.18 D 2 = variable R 3 = -53.00 D 3 = 1.20 N 2 = 1.69679 ν 2 = 55.5 R 4 = 23.65 D 4 = Variable R 5 = 15.02 D 5 = 1.20 N 3 = 1.84665 ν 3 = 23.8 R 6 = 15.55 D 6 = 3.50 N 4 = 1.58913 ν 4 = 61.2 R 7 = -22.14 D 7 = 1.00 N 5 = 1.84665 ν 5 = 23.8 R 8 = -51.78 D 8 = Variable R 9 = Aperture D 9 = 3.59 R10 = -20.71 D10 = 1.20 N 6 = 1.80518 ν 6 = 25.4 R11 = -86.49 D11 = Variable R12 = Fixed Aperture D12 = 2.80 R13 = 3202.97 D13 = 4.60 N 7 = 1.78589 ν 7 = 44.2 R14 = -15.18 D14 = Variable R15 = -26.57 D15 = 1.20 N 8 = 1.77249 ν 8 = 49.6 R16 = 74.12 D16 = 2.20 N 9 = 1.80518 ν 9 = 25.4 R17 = 266.07 D17 = 2.01 R18 = -64.20 D18 = 1.50 N10 = 1.69679 ν10 = 55.5 R19 = -13681.8

【００６６】[0066]

【表７】 [Table 7]

【００６７】[0067]

【発明の効果】本発明によれば以上のように、全体とし
て４つのレンズ群より構成し、変倍における各レンズ群
の移動条件や屈折力等を適切に設定することにより広角
端の撮影画角が７４°程度、変倍比３．５程度の全変倍
範囲にわたり高い光学性能を有したズームレンズを達成
することができる。As described above, according to the present invention, as a whole, it is composed of four lens groups, and by appropriately setting the moving condition, the refractive power, etc. of each lens group during zooming, a photographed image at the wide-angle end is obtained. It is possible to achieve a zoom lens having high optical performance over the entire zoom range with an angle of about 74 ° and a zoom ratio of about 3.5.

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

【図１】 本発明のズームレンズの近軸屈折力配置の
説明図FIG. 1 is an explanatory view of a paraxial refractive power arrangement of a zoom lens according to the present invention.

【図２】 本発明のズームレンズの近軸屈折力配置の
説明図FIG. 2 is an explanatory diagram of a paraxial refractive power arrangement of the zoom lens of the present invention.

【図３】 本発明のズームレンズの近軸屈折力配置の
説明図FIG. 3 is an explanatory diagram of a paraxial refractive power arrangement of the zoom lens of the present invention.

【図４】 本発明の数値実施例１の広角端のレンズ断
面図FIG. 4 is a lens cross-sectional view at a wide-angle end according to Numerical Example 1 of the present invention.

【図５】 本発明の数値実施例２の広角端のレンズ断
面図FIG. 5 is a lens cross-sectional view at a wide-angle end according to Numerical Example 2 of the present invention.

【図６】 本発明の数値実施例３の広角端のレンズ断
面図FIG. 6 is a lens cross-sectional view at a wide-angle end according to Numerical Example 3 of the present invention.

【図７】 本発明の数値実施例４の広角端のレンズ断
面図FIG. 7 is a lens cross-sectional view at a wide-angle end according to Numerical Example 4 of the present invention.

【図８】 本発明の数値実施例５の広角端のレンズ断
面図FIG. 8 is a lens cross-sectional view at a wide-angle end according to Numerical Example 5 of the present invention.

【図９】 本発明の数値実施例６の広角端のレンズ断
面図FIG. 9 is a lens cross-sectional view at a wide-angle end according to Numerical Example 6 of the present invention.

【図１０】 本発明の数値実施例７の広角端のレンズ断
面図FIG. 10 is a lens cross-sectional view at a wide-angle end according to Numerical Embodiment 7 of the present invention.

【図１１】 本発明の数値実施例１の広角端の収差図FIG. 11 is an aberration diagram at the wide-angle end according to Numerical Example 1 of the present invention.

【図１２】 本発明の数値実施例１の中間の収差図FIG. 12 is an intermediate aberration diagram of Numerical example 1 of the present invention.

【図１３】 本発明の数値実施例１の望遠端の収差図FIG. 13 is an aberration diagram at a telephoto end according to Numerical Example 1 of the present invention.

【図１４】 本発明の数値実施例２の広角端の収差図FIG. 14 is an aberration diagram at the wide-angle end according to Numerical Example 2 of the present invention.

【図１５】 本発明の数値実施例２の中間の収差図FIG. 15 is an intermediate aberration diagram of Numerical example 2 of the present invention.

【図１６】 本発明の数値実施例２の望遠端の収差図FIG. 16 is an aberration diagram at a telephoto end according to Numerical Example 2 of the present invention.

【図１７】 本発明の数値実施例３の広角端の収差図FIG. 17 is an aberration diagram at a wide-angle end according to Numerical Example 3 of the present invention.

【図１８】 本発明の数値実施例３の中間の収差図FIG. 18 is an intermediate aberration diagram of Numerical example 3 of the present invention.

【図１９】 本発明の数値実施例３の望遠端の収差図FIG. 19 is an aberration diagram at a telephoto end according to Numerical Example 3 of the present invention.

【図２０】 本発明の数値実施例４の広角端の収差図FIG. 20 is an aberration diagram at a wide-angle end according to Numerical Example 4 of the present invention.

【図２１】 本発明の数値実施例４の中間の収差図FIG. 21 is an intermediate aberration diagram of Numerical Example 4 of the present invention.

【図２２】 本発明の数値実施例４の望遠端の収差図FIG. 22 is an aberration diagram at a telephoto end according to Numerical Example 4 of the present invention.

【図２３】 本発明の数値実施例５の広角端の収差図FIG. 23 is an aberration diagram at a wide-angle end according to Numerical Example 5 of the present invention.

【図２４】 本発明の数値実施例５の中間の収差図FIG. 24 is an intermediate aberration diagram of Numerical Example 5 of the present invention.

【図２５】 本発明の数値実施例５の望遠端の収差図FIG. 25 is an aberration diagram at a telephoto end according to Numerical Example 5 of the present invention.

【図２６】 本発明の数値実施例６の広角端の収差図FIG. 26 is an aberration diagram at a wide-angle end according to Numerical Example 6 of the present invention.

【図２７】 本発明の数値実施例６の中間の収差図FIG. 27 is an intermediate aberration diagram of Numerical Example 6 of the present invention.

【図２８】 本発明の数値実施例６の望遠端の収差図FIG. 28 is an aberration diagram at a telephoto end according to Numerical Example 6 of the present invention.

【図２９】 本発明の数値実施例７の広角端の収差図FIG. 29 is an aberration diagram at the wide-angle end according to Numerical Example 7 of the present invention.

【図３０】 本発明の数値実施例７の中間の収差図FIG. 30 is an intermediate aberration diagram of Numerical Example 7 of the present invention.

【図３１】 本発明の数値実施例７の望遠端の収差図FIG. 31 is an aberration diagram at a telephoto end according to Numerical Example 7 of the present invention.

【図３２】 本発明の数値実施例５の３次軸上色収差係
数の説明図FIG. 32 is an explanatory diagram of a cubic axial chromatic aberration coefficient according to Numerical Example 5 of the present invention.

【図３３】 本発明の数値実施例５の３次倍率色収差係
数の説明図FIG. 33 is an explanatory diagram of a third-order magnification chromatic aberration coefficient according to Numerical Example 5 of the present invention.

【図３４】 本発明の数値実施例５の３次球面収差係数
の説明図FIG. 34 is an explanatory diagram of a third-order spherical aberration coefficient according to Numerical Example 5 of the present invention.

【符号の説明】[Explanation of symbols]

Ｌ１ 第１群 Ｌ２ 第２群 Ｌ３ 第３群 Ｌ４ 第４群 ＳＰ 絞り ＳＰＰ 固定絞り ＩＰ 像面 ｄ ｄ線 ｇ ｇ線 Ｓ．Ｃ 正弦条件 ΔＳ サジタル像面 ΔＭ メリディオナル像面 L1 first group L2 second group L3 third group L4 fourth group SP diaphragm SPP fixed diaphragm IP image plane d d line g g line S.I. C Sine condition ΔS Sagittal image plane ΔM Meridional image plane

Claims (14)

【特許請求の範囲】[Claims] 【請求項１】 物体側より順に広角端において単一又は
複数のレンズ群を有する全体として負の屈折力の第１
群、正の屈折力の第２群、単一又は複数のレンズ群を有
する全体として正の屈折力の第３群、そして負の屈折力
の第４群の４つのレンズ群を有し、各レンズ群を移動さ
せて変倍を行う際、第ｉ群（ｉ≧２）の広角端と望遠端
の横倍率を各々βｉＷ，βｉＴとし、第ｉ群の変倍率Δ
βｉを Δβｉ＝｜βｉＴ／βｉＷ｜ とおいたとき、該第２群は正の屈折力のレンズ群中、Δ
βｉ＞１なる条件で最も変倍率が大きく、且つ２枚の正
レンズ又は２枚の負レンズとそれらと逆の屈折力の１つ
のレンズとを接合した全体として正の屈折力の３枚貼合
わせレンズを有していることを特徴とするズームレン
ズ。1. A first lens having a negative refracting power as a whole having a single or a plurality of lens groups at the wide-angle end in order from the object side.
Group, a second group having a positive refractive power, a third group having a positive refractive power as a whole having a single lens group or a plurality of lens groups, and a fourth group having a negative refractive power, each having four lens groups, When performing zooming by moving the lens units, the lateral magnifications of the wide-angle end and the telephoto end of the i-th group (i ≧ 2) are set to βiW and βiT, respectively, and the scaling ratio Δ of the i-th group is set.
When βi is set as Δβi = | βiT / βiW |, the second group is Δ
Under the condition of βi> 1, the largest zoom ratio is obtained, and two positive lenses or two negative lenses and one lens having the opposite refractive power are cemented together, and three pieces having a positive refractive power are bonded as a whole. A zoom lens having a lens. 【請求項２】 広角端に対し、望遠端において該第１群
と第２群の間隔及び該第３群と第４群の間隔が小とな
り、該第２群と第３群の間隔が大となるように各レンズ
群を光軸上移動させて変倍を行っていることを特徴とす
る請求項１のズームレンズ。2. The distance between the first group and the second group and the distance between the third group and the fourth group are small at the telephoto end with respect to the wide angle end, and the distance between the second group and the third group is large. The zoom lens according to claim 1, wherein each of the lens units is moved along the optical axis so that the zooming is performed. 【請求項３】 変倍領域において最も大きな変倍率を有
する負の屈折力のレンズ群の焦点距離をＦＣ、広角端に
おける全系の焦点距離をＦＷとしたとき ０．５＜｜ＦＣ／ＦＷ｜＜１．２ なる条件を満足することを特徴とする請求項１のズーム
レンズ。3. When the focal length of the lens unit having a negative refractive power and having the largest magnification in the zoom region is FC, and the focal length of the entire system at the wide-angle end is FW, 0.5 <| FC / FW | The zoom lens according to claim 1, wherein the condition <1.2 is satisfied. 【請求項４】 前記３枚貼合わせレンズは物体側より順
に物体側に凸面を向けたメニスカス状のレンズ、両レン
ズ面が凸面の正レンズ、像面側に凸面を向けたメニスカ
ス状のレンズより成っていることを特徴とする請求項１
又は３のズームレンズ。4. The three-lens cemented lens comprises a meniscus lens whose convex surface faces the object side in order from the object side, a positive lens whose both lens surfaces are convex surfaces, and a meniscus lens whose convex surface faces the image surface side. Claim 1 characterized by being formed.
Or 3 zoom lens. 【請求項５】 前記第２群より像面側に絞りが配置され
ていることを特徴とする請求項４のズームレンズ。5. The zoom lens according to claim 4, wherein a stop is arranged closer to the image surface side than the second lens group. 【請求項６】 前記第１群と第２群の広角端における合
成焦点距離をＦ１，２Ｗ、広角端における全系の焦点距
離をＦＷとしたとき ０．８＜Ｆ１，２Ｗ／ＦＷ＜１．７ なる条件を満足することを特徴とする請求項５のズーム
レンズ。6. When the combined focal length of the first group and the second group at the wide-angle end is F1 and W, and the focal length of the entire system at the wide-angle end is FW, 0.8 <F1,2W / FW <1. 7. The zoom lens according to claim 5, wherein the condition 7 is satisfied. 【請求項７】 前記３枚貼合わせレンズの物体側からｉ
番目のレンズの材質のアッベ数をνＡｉ、ｉ番目のレン
ズ面の曲率半径をＲＡｉ、該３枚貼合わせレンズの焦点
距離をＦＡとしたとき ０．６＜ＦＡ／ＦＷ＜１．３ ２０＜νＡ２−（νＡ１＋νＡ３）／２ ０．１３＜（ＲＡ３＋ＲＡ２）／（ＲＡ３−ＲＡ２）＜
０．４５ なる条件を満足することを特徴とする請求項４又は６の
ズームレンズ。7. The i from the object side of the three-piece cemented lens
When the Abbe number of the material of the th lens is νAi, the radius of curvature of the i-th lens surface is RAi, and the focal length of the three cemented lens is FA, 0.6 <FA / FW <1.3 20 <νA2 -(ΝA1 + νA3) / 2 0.13 <(RA3 + RA2) / (RA3-RA2) <
7. The zoom lens according to claim 4, wherein the condition of 0.45 is satisfied. 【請求項８】 物体側より順に広角端において単一又は
複数のレンズ群を有する全体として負の屈折力の第１
群、正の屈折力の第２群、単一又は複数のレンズ群を有
する全体として正の屈折力の第３群、そして負の屈折力
の第４群の４つのレンズ群を有し、各レンズ群を移動さ
せて変倍を行う際、該第２群は２枚の正レンズ又は２枚
の負レンズとそれらと逆の屈折力の１つのレンズとを接
合した全体として正の屈折力の３枚貼合わせレンズを有
しており、該第２群よりも像面側に焦点距離をＦＢ（Ｆ
Ｂ＜０）、広角端における全系の焦点距離をＦＷとした
とき ｜ＦＢ／ＦＷ｜＜１．１ 成る条件を満足する負の屈折力のレンズ群が設けられて
いることを特徴とするズームレンズ。8. A first lens having a negative refracting power as a whole having a single or a plurality of lens groups at the wide-angle end in order from the object side.
Group, a second group having a positive refractive power, a third group having a positive refractive power as a whole having a single lens group or a plurality of lens groups, and a fourth group having a negative refractive power, each having four lens groups, When the lens group is moved to perform the magnification change, the second group has a positive refractive power as a whole in which two positive lenses or two negative lenses and one lens having the opposite refractive power are cemented. It has a three-piece cemented lens and has a focal length FB (F
B <0), when the focal length of the entire system at the wide-angle end is FW, a zoom lens is provided which has a negative refractive power lens group that satisfies the condition | FB / FW | <1.1. lens. 【請求項９】 広角端に対し、望遠端において該第１群
と第２群の間隔及び該第３群と第４群の間隔が小とな
り、該第２群と第３群の間隔が大となるように各レンズ
群を光軸上移動させて変倍を行っていることを特徴とす
る請求項８のズームレンズ。9. The distance between the first group and the second group and the distance between the third group and the fourth group are small at the telephoto end with respect to the wide angle end, and the distance between the second group and the third group is large. 9. The zoom lens according to claim 8, wherein each of the lens groups is moved on the optical axis so that zooming is performed. 【請求項１０】 変倍領域において最も大きな変倍率を
有する負の屈折力のレンズ群の焦点距離をＦＣ、広角端
における全系の焦点距離をＦＷとしたとき ０．５＜｜ＦＣ／ＦＷ｜＜１．２ なる条件を満足することを特徴とする請求項８のズーム
レンズ。10. When the focal length of the lens unit having a negative refractive power and having the largest magnification in the zoom region is FC, and the focal length of the entire system at the wide-angle end is FW, 0.5 <| FC / FW | The zoom lens according to claim 8, wherein the condition <1.2 is satisfied. 【請求項１１】 前記３枚貼合わせレンズは物体側より
順に物体側に凸面を向けたメニスカス状のレンズ、両レ
ンズ面が凸面の正レンズ、像面側に凸面を向けたメニス
カス状のレンズより成っていることを特徴とする請求項
８又は１０のズームレンズ。11. The three-piece cemented lens comprises a meniscus lens having convex surfaces facing the object side in order from the object side, a positive lens having convex lens surfaces on both sides, and a meniscus lens having convex surfaces facing the image surface side. The zoom lens according to claim 8 or 10, wherein the zoom lens is formed. 【請求項１２】 前記第２群より像面側に絞りが配置さ
れていることを特徴とする請求項１１のズームレンズ。12. The zoom lens according to claim 11, wherein a stop is arranged closer to the image surface side than the second lens group. 【請求項１３】 前記第１群と第２群の広角端における
合成焦点距離をＦ１，２Ｗ、広角端における全系の焦点
距離をＦＷとしたとき ０．８＜Ｆ１，２Ｗ／ＦＷ＜１．７ なる条件を満足することを特徴とする請求項１２のズー
ムレンズ。13. When the combined focal length of the first group and the second group at the wide-angle end is F1 and W, and the focal length of the entire system at the wide-angle end is FW, 0.8 <F1,2W / FW <1. 13. The zoom lens according to claim 12, wherein the condition 7 is satisfied. 【請求項１４】 前記３枚貼合わせレンズの物体側から
ｉ番目のレンズの材質のアッベ数をνＡｉ、ｉ番目のレ
ンズ面の曲率半径をＲＡｉ、該３枚貼合わせレンズの焦
点距離をＦＡとしたとき ０．６＜ＦＡ／ＦＷ＜１．３ ２０＜νＡ２−（νＡ１＋νＡ３）／２ ０．１３＜（ＲＡ３＋ＲＡ２）／（ＲＡ３−ＲＡ２）＜
０．４５ なる条件を満足することを特徴とする請求項１１又は１
３のズームレンズ。14. The Abbe number of the material of the i-th lens from the object side of the triple-bonded lens is νAi, the radius of curvature of the i-th lens surface is RAi, and the focal length of the triple-bonded lens is FA. 0.6 <FA / FW <1.3 20 <νA2- (νA1 + νA3) / 2 0.13 <(RA3 + RA2) / (RA3-RA2) <
The condition of 0.45 is satisfied, or the condition is satisfied.
3 zoom lens.