JPH05281470A

JPH05281470A - Small-sized two-group zoom lens

Info

Publication number: JPH05281470A
Application number: JP4102413A
Authority: JP
Inventors: Yasushi Ogata; 康司小方
Original assignee: Olympus Optical Co Ltd
Current assignee: Olympus Corp
Priority date: 1992-03-30
Filing date: 1992-03-30
Publication date: 1993-10-29
Anticipated expiration: 2017-10-07
Also published as: JP3331223B2

Abstract

PURPOSE:To decrease the number of constituent elements and to obtain the compact zoom lens with high performance by composing the zoom lens of a positive lens element and a negative lens element in order from the object side and making at least one of negative lens element surfaces aspherical. CONSTITUTION:The front group consists of two elements in two groups, i.e., a negative and a positive lens in order from the object side and has one or two aspherical surfaces. The rear group, on the other hand, consists of a positive lens element and a negative lens element; and the positive lens element is a single lens or cemented lens and the negative lens elements are all single lenses. The rear group, therefore, consists of two elements in two groups or three elements in two groups and has one-three aspherical surfaces. Further, this lens system satisfies conditions shown by inequalities. In the inequalities, f1 and f2 are the focal lengths of the front and rear groups and fw is the focal length of the whole system at the wide-angle end.

Description

Detailed Description of the Invention

【０００１】[0001]

【産業上の利用分野】本発明は、負の屈折力の前群と正
の屈折力の後群からなる小型の２群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 two-group zoom lens including a front group having a negative refractive power and a rear group having a positive refractive power.

【０００２】[0002]

【従来の技術】従来より、このタイプの負，正の２群ズ
ームレンズは、１眼レフレックスカメラ用の交換レンズ
として、標準画角を含むいわゆる標準ズームレンズとし
て広く利用されてきた。この種の２群ズームレンズは、
負の屈折力の前群と正の屈折力の後群の２つの群を離し
て配置する、レトロフォーカスの近軸配置を構成してい
るから、１眼レフレックスカメラのクイックリターンミ
ラーを装着するに必要な、長いバックフォーカスを確保
し易く、全体にコンパクトにまとまる上、良好な性能を
得ることが容易である。2. Description of the Related Art Conventionally, a negative and positive two-group zoom lens of this type has been widely used as an interchangeable lens for a single-lens reflex camera and a so-called standard zoom lens including a standard angle of view. This kind of 2 group zoom lens,
Since a retrofocus paraxial arrangement in which the front lens group with negative refracting power and the rear lens group with positive refracting power are arranged separately, a quick return mirror of a single-lens reflex camera is mounted. It is easy to secure a long back focus, which is necessary for the above, and it is easy to obtain good performance in addition to being compacted as a whole.

【０００３】このような負，正の２群ズームタイプにお
いて、構成枚数を少なくした従来例として、特開昭５９
−６４８１１号公報に記載されたレンズ系が知られてい
る。このレンズ系は、およそ３５〜７０mmの焦点距離を
持つズームレンズであるが、前群を２群２枚、後群を４
群４枚にて構成したものであり、前群中に非球面を設け
ることによって収差補正を行っている。As a conventional example in which the number of constituent elements is reduced in such a negative and positive two-group zoom type, Japanese Patent Laid-Open No. 59-59
A lens system described in Japanese Patent Publication No. -64811 is known. This lens system is a zoom lens with a focal length of about 35 to 70 mm, with two lenses in the front group and four lenses in the rear group.
It is composed of four lens groups, and aberration is corrected by providing an aspherical surface in the front lens group.

【０００４】一方、このタイプのレンズ系をレンズシャ
ッターカメラに適用した例として、特開昭６２−５０７
１８号公報に記載されたレンズ系が知られている。レン
ズシャッターカメラでは、バックフォーカスを長くしな
ければならないと云う要求がないので、その分、全長短
縮が可能である。その上この従来例は後群の構成を正の
屈折力と負の屈折力を離して配置する、いわゆるテレフ
ォトの近軸配置とすることにより一層の全長短縮を図っ
ている。このレンズ系は、およそ３５〜７０mmの焦点距
離をもち、前群を３群３枚、後群を４群６枚にて構成
し、前群と後群の両方に非球面を設けることにより収差
補正を行っている。On the other hand, as an example of applying this type of lens system to a lens shutter camera, Japanese Patent Laid-Open No. 62-507.
The lens system described in Japanese Patent No. 18 is known. Since the lens shutter camera does not require the back focus to be long, the total length can be shortened accordingly. Furthermore, in this conventional example, the total length is further shortened by adopting a so-called telephoto paraxial arrangement in which the rear lens group is arranged so that the positive refractive power and the negative refractive power are separated from each other. This lens system has a focal length of about 35 to 70 mm, the front lens group is composed of 3 lenses in 3 groups, the rear lens group is composed of 6 lenses in 4 groups, and an aspherical surface is provided in both the front lens group and the rear lens group. We are making corrections.

【０００５】[0005]

【発明が解決しようとする課題】前述の従来例のうち、
特開昭５９−６４８１１号公報のレンズ系は、６枚構成
で少ないレンズ枚数であるが、各群への屈折力配分の設
定上、前群の有効径が大きくなってしまうため、コンパ
クトさの点で好ましくない。更に、前群に含まれる２枚
のレンズは有効径が大きいために、その材料費，加工費
ともに高くなってしまい好ましくない。特に、広角端の
焦点距離を短くして、より広画角化を図った場合に、そ
の欠点が顕著になる。Of the above-mentioned conventional examples,
The lens system disclosed in Japanese Patent Laid-Open No. 59-64811 has a small number of lenses with a six-lens configuration, but is small in size because the effective diameter of the front group becomes large due to the setting of the refractive power distribution to each group. It is not preferable in terms. Further, since the two lenses included in the front group have large effective diameters, both material cost and processing cost are high, which is not preferable. In particular, when the focal length at the wide-angle end is shortened to achieve a wider angle of view, the drawback becomes remarkable.

【０００６】又、特開昭６２−５０７１８号公報のレン
ズ系は、全長，有効径ともに小型化されているものの、
全系で９枚ものレンズが使われており、コスト的に好ま
しくない。The lens system disclosed in Japanese Patent Laid-Open No. 62-50718 has a small overall length and an effective diameter.
As many as nine lenses are used in the entire system, which is not preferable in terms of cost.

【０００７】本発明は負の屈折力の前群と正の屈折力の
後群からなり構成枚数が少なく、コンパクトで高性能な
２群ズームレンズを提供することを目的としている。An object of the present invention is to provide a compact and high-performance two-group zoom lens composed of a front group having a negative refracting power and a rear group having a positive refracting power and having a small number of constituent elements.

【０００８】更に広画角で、高変倍比のズームレンズを
提供することを目的とするものである。It is another object of the present invention to provide a zoom lens having a wide angle of view and a high zoom ratio.

【０００９】[0009]

【課題を解決するための手段】本発明のズームレンズ
は、負の屈折力の前群と正の屈折力の後群にて構成さ
れ、両群間の間隔を変えて変倍を行なうもので、後群が
物体側より順に、正レンズ成分と負レンズ成分にて構成
され、前記の負レンズ成分中に少なくとも１面非球面を
設けたレンズ系である。A zoom lens according to the present invention comprises a front group having a negative refracting power and a rear group having a positive refracting power, and performs zooming by changing an interval between the two groups. The rear lens group is composed of a positive lens component and a negative lens component in order from the object side, and at least one aspherical surface is provided in the negative lens component.

【００１０】更に本発明のレンズ系は、下記の条件
（１），（２）を満足する。（１）１＜｜ｆ₁|／ｆ_W ＜２（２）０．７＜ｆ₂ ／ｆ_W ＜１．４ただし、ｆ₁ ，ｆ₂ は夫々前群および後群の焦点距離、
ｆ_W は広角端における全系の焦点距離である。Further, the lens system of the present invention satisfies the following conditions (1) and (2). (1) 1 <| f ₁ | / f _W <2 (2) 0.7 <f ₂ / f _W <1.4 where f ₁ and f ₂ are the focal lengths of the front group and the rear group, respectively.
f _W is the focal length of the entire system at the wide-angle end.

【００１１】本発明は、レンズ構成枚数を極力減らすこ
とを狙いとしているが、その場合いかにして高性能を維
持するかが問題になってくる。レンズ枚数が極めて少な
くしかも良好な光学性能を有するレンズ系を得るために
は、収差補正の中でも特に、色収差補正のために後群を
正レンズ成分と負レンズ成分の２つの成分にて構成する
のが良い。更に、軸外収差、特に、非点収差，歪曲収差
を良好に補正するために、前記後群の負レンズ成分中に
少なくとも１面の非球面を設ける必要がある。The present invention aims to reduce the number of lens components as much as possible, but in that case, how to maintain high performance becomes a problem. In order to obtain a lens system having an extremely small number of lenses and good optical performance, the rear group is composed of two components, a positive lens component and a negative lens component, for chromatic aberration correction, in particular for aberration correction. Is good. Furthermore, in order to satisfactorily correct off-axis aberrations, particularly astigmatism and distortion, it is necessary to provide at least one aspherical surface in the negative lens component of the rear group.

【００１２】一方、構成枚数を少なくしてコストダウン
を達成したとしても、レンズ系が巨大なものになっては
商品価値がない。そこで、前記の通りの少ない枚数のレ
ンズ構成にて、十分なコンパクトさと高性能を達成する
ためには、まず、前，後群に適切な屈折力配分を与える
ことが必要である。そのために設けたのが前記の条件で
あって、条件（１）は前群の焦点距離、条件（２）は後
群の焦点距離を規定するものである。On the other hand, even if the number of constituent elements is reduced to achieve cost reduction, the lens system becomes huge and has no commercial value. Therefore, in order to achieve sufficient compactness and high performance with the lens configuration of a small number of lenses as described above, it is first necessary to give appropriate refractive power distribution to the front and rear groups. The above conditions are provided for that purpose. Condition (1) defines the focal length of the front group, and condition (2) defines the focal length of the rear group.

【００１３】既に、良く知られているように、負．正の
レンズ群よりなる２群ズームタイプのレンズ系は、中間
焦点距離ｆ_S ｛ｆ_W ，ｆ_T を夫々広角端、望遠端におけ
る全系焦点距離とした時、ｆ_S ＝（ｆ_W・ｆ_T）^1/2ｆ_W
・ｆ_T ｝にて、後群が等倍結像となる場合に、変倍に伴
う前群の移動量が最小となる。、本発明では、前群の移
動量を少なくすることと収差補正の可能性とを考慮し
て、条件（１）を満足するように第１群の焦点距離を定
めることによって、中間焦点距離から広角端の間に、後
群の等倍結像位置があるようにしている。従って、条件
（１）の上限をこえると、自ずから前群の移動量が大き
くなり、更に、前群と後群の間隔が広がるため前群の有
効径が大きくなり好ましくない。また、条件（１）の下
限をこえると、少ないレンズ構成枚数では十分な収差補
正が出来なくなる。As is well known, negative. When the intermediate focal lengths f _S {f _W and f _T are the focal lengths of the entire system at the wide-angle end and the telephoto end, respectively, f _S = (f _W · f _T ) ^1/2 f _W
At f _T }, the amount of movement of the front group due to zooming is minimized when the rear group forms an image of the same magnification. In the present invention, the focal length of the first lens unit is determined so as to satisfy the condition (1) in consideration of the reduction in the amount of movement of the front lens unit and the possibility of aberration correction. The same-magnification image formation position of the rear group is arranged between the wide-angle ends. Therefore, if the upper limit of the condition (1) is exceeded, the amount of movement of the front group naturally increases, and further the distance between the front group and the rear group widens, so that the effective diameter of the front group increases, which is not preferable. Further, if the lower limit of the condition (1) is exceeded, sufficient aberration correction cannot be performed with a small number of lens components.

【００１４】条件（２）は、後群の変倍に伴う移動量と
収差補正の可能性とから設定した条件である。後群の屈
折力が強い程、その移動量を少なくできるが、後群の屈
折力を、条件（２）の下限を越えて強くすると本発明の
レンズ構成では十分な収差補正が出来なくなる。一方、
条件（２）の上限を越えて後群の屈折力が弱くなると、
後群の移動量が大きくなる上に、前群と後群の間隔が広
がるため前群の有効径が大きくなり好ましくない。The condition (2) is a condition set from the movement amount and the possibility of aberration correction associated with the zooming of the rear group. The stronger the refracting power of the rear group is, the smaller the amount of movement thereof can be. However, if the refracting power of the rear group is made stronger than the lower limit of the condition (2), the lens structure of the present invention cannot correct aberrations sufficiently. on the other hand,
When the upper limit of the condition (2) is exceeded and the refractive power of the rear group becomes weak,
This is not preferable because the amount of movement of the rear group increases and the effective diameter of the front group increases because the distance between the front group and the rear group increases.

【００１５】更に、本発明のレンズ系において良好な収
差補正を達成するために、後群中の負レンズ成分に非球
面を用いることが重要であるが、このとき少なくとも１
面の非球面は下記条件（３）を満足することが望まし
い。（３）０＜Δ_R2／φ_R2 ただしΔ_R2は後群中の負のレンズ成分中に設けられた非
球面の有効半径における非球面量、φ_R2は上記非球面の
近軸曲率半径をｒ_R2、非球面の前後の媒質の屈折率を夫
々ｎ_R2，ｎ'_R2 とした時、下記の式にて与えられる値で
ある。 φ_R2＝（ｎ'_R2 −ｎ_R2）／ｒ_R2 条件（３）は非球面の形状を定めたもので、その形状
が、光軸から離れるに従って徐々に負の屈折力を強める
ような非球面形状であることを示している。条件（３）
を外れると、広角端における非点収差，歪曲収差の補正
が十分でなくなる。Further, in order to achieve good aberration correction in the lens system of the present invention, it is important to use an aspherical surface for the negative lens component in the rear lens group.
It is desirable that the aspherical surface should satisfy the following condition (3). (3) 0 <Δ _R2 / φ _{R2 where} Δ _R2 is the aspherical amount in the effective radius of the aspherical surface provided in the negative lens component in the rear group, and φ _R2 is the paraxial radius of curvature of the aspherical surface. _R2 is the value given by the following formula, where n _R2 and n ′ _R2 are the refractive indices of the media before and after the aspherical surface, respectively. φ _R2 = (n ′ _R2 −n _R2 ) / r _R2 Condition (3) defines the shape of the aspherical surface, and the shape is such that the negative refractive power gradually increases as the distance from the optical axis increases. It shows that it is a shape. Condition (3)
If deviating from the range, the correction of astigmatism and distortion at the wide-angle end becomes insufficient.

【００１６】又、後群中の正レンズ成分のアッベ数をν
₂₁とすると、このアッベ数ν₂₁が下記条件（４）を満足
することが望ましい。（４）７０＜ν₂₁ ここでν₂₁は、正レンズ成分が接合レンズ等の複数のレ
ンズよりなる場合は、正レンズ及び負レンズ等含まれる
全てのレンズのアッベ数の和とする。Also, the Abbe number of the positive lens component in the rear group is ν
_{If it is 21} , it is desirable that this Abbe number ν ₂₁ satisfies the following condition (4). (4) 70 <ν ₂₁ Here, ν ₂₁ is the sum of the Abbe numbers of all the lenses including the positive lens and the negative lens when the positive lens component includes a plurality of lenses such as cemented lenses.

【００１７】後群の屈折力は正レンズ成分が担ってお
り、色収差を補正するためには、この正レンズ成分と負
レンズ成分との打ち消し合いが望ましい。しかし後述の
実施例にもあるように、負レンズ成分の屈折力は必ずし
も強くなくても良いので、変倍に伴う色収差の変動を抑
えるためには、正レンズ成分での色収差発生を抑えてお
くことが望ましい。ν₂₁が条件（４）を満足すれば、負
レンズ成分の屈折力が強い場合でも、より良い収差補正
が可能である。The positive lens component is responsible for the refracting power of the rear group, and it is desirable to cancel out the positive lens component and the negative lens component in order to correct chromatic aberration. However, as will be described later in Examples, the refractive power of the negative lens component does not necessarily have to be strong. Therefore, in order to suppress variation in chromatic aberration due to zooming, generation of chromatic aberration in the positive lens component is suppressed. Is desirable. If ν ₂₁ satisfies the condition (4), better aberration correction is possible even if the negative lens component has a strong refractive power.

【００１８】一方、前群の構成は物体側より順に、負レ
ンズ成分と正レンズ成分にて構成し、少なくとも１面の
非球面を有することが、一層好ましい。このように、前
群中に非球面を設けるとき、この非球面は下記条件
（５）を満足することが望ましい。（５）０＜Δ_F ／φ_F ただしφ_F は、ｒ_F を前群に設けられた非球面の近軸曲
率半径、ｎ_F ，ｎ'_Fを夫々非球面の前後の媒質の屈折率
としたとき下記の式で表わされる値、Δ_F は有効半径に
おける非球面量である。 φ_F ＝（ｎ'_F−ｎ_F ）／ｒ_F 条件（５）は条件（３）と同様に、非球面の形状が、光
軸から離れるにしたがって徐々に負の屈折力を強めるよ
うな形状であることを示すものである。On the other hand, it is more preferable that the front lens group has a negative lens component and a positive lens component in order from the object side, and has at least one aspherical surface. Thus, when the aspherical surface is provided in the front group, it is desirable that this aspherical surface satisfy the following condition (5). _{(5) 0 <Δ F /} φ F However phi _F is a refractive index before and after the medium aspherical paraxial radius of curvature of which is provided a r _F in the front group, n _F, n _'F respectively aspherical Then, the value represented by the following equation, Δ _F, is the amount of aspherical surface at the effective radius. φ _F = (n ′ _F −n _F ) / r _{F The} condition (5) is similar to the condition (3) such that the shape of the aspherical surface gradually increases the negative refracting power with increasing distance from the optical axis. It means that.

【００１９】この条件（５）を満足する非球面を前群中
に用いれば、非点収差，歪曲収差を一層良好に補正する
上で望ましい。It is desirable to use an aspherical surface satisfying the condition (5) in the front lens group, in order to more satisfactorily correct astigmatism and distortion.

【００２０】又、前記後群中の正レンズ成分の焦点距離
をｆ_R1とすると下記条件（６）を満足することが望まし
い。（６）０．５＜ｆ_R1／ｆ₂ ＜１条件（６）の上限は、後群中の負レンズ成分の屈折力が
０であることを意味するから、この上限を越えることは
ない。一方、条件（６）の下限を越えた場合、正レンズ
成分と負レンズ成分はともに屈折力が強くなり本発明の
構成では十分な収差補正ができない。Further, when the focal length of the positive lens component in the rear group is f _R1 , it is desirable to satisfy the following condition (6). (6) 0.5 <f _R1 / f ₂ <1 The upper limit of the condition (6) means that the refractive power of the negative lens component in the rear group is 0, and therefore it does not exceed this upper limit. On the other hand, when the value goes below the lower limit of the condition (6), both the positive lens component and the negative lens component have strong refracting power, and the aberration of the present invention cannot be sufficiently corrected.

【００２１】前記後群中の正レンズ成分の全厚みをｄ_R1
とすると下記条件（７）を満足することが望ましい。（７）０．１＜ｄ_R1／ｆ₂ ＜０．５条件（７）の下限を越えると、非点収差の補正が十分で
なくなる。一方、条件（７）の上限を越えると収差補正
上は有利だが、レンズ系全長の増大を招き好ましくな
い。The total thickness of the positive lens component in the rear group is d _R1
Then, it is desirable to satisfy the following condition (7). (7) 0.1 <d _R1 / f ₂ <0.5 If the lower limit of condition (7) is exceeded, the correction of astigmatism will be insufficient. On the other hand, when the value exceeds the upper limit of the condition (7), it is advantageous for aberration correction, but it is not preferable because it causes an increase in the entire length of the lens system.

【００２２】[0022]

【実施例】次に本発明の小型な２群ズームレンズの各実
施例を示す。実施例１ｆ＝35〜49.5〜70mm ，Ｆ／4.6 〜Ｆ／5.45〜Ｆ／6.67 ２ω＝63.36 〜47.15 〜34.30 °，ｆ_B ＝43.3〜53.3〜67.4mm ｒ₁ ＝83.3070 （非球面）ｄ₁ ＝1.8000 ｎ₁ ＝1.72000 ν₁ ＝46.03 ｒ₂ ＝17.0980 ｄ₂ ＝6.3600 ｒ₃ ＝20.2750 ｄ₃ ＝3.0000 ｎ₂ ＝1.78472 ν₂ ＝25.68 ｒ₄ ＝27.2690 ｄ₄ ＝Ｄ（可変）ｒ₅ ＝∞（絞り）ｄ₅ ＝1.0000 ｒ₆ ＝15.1410 （非球面）ｄ₆ ＝7.7700 ｎ₃ ＝1.58913 ν₃ ＝61.18 ｒ₇ ＝-16.6450 ｄ₇ ＝1.5000 ｎ₄ ＝1.59270 ν₄ ＝35.29 ｒ₈ ＝150.1760 ｄ₈ ＝4.6600 ｒ₉ ＝-196.3710 (非球面）ｄ₉ ＝1.8000 ｎ₅ ＝1.67790 ν₅ ＝50.72 ｒ₁₀＝101.1350 非球面係数（ｒ₁ 面）Ｐ＝0.9806，Ａ₄ ＝0.12526 ×10^-5 ，Ａ₆ ＝0.19987 ×10^-8 ，Ａ₈ ＝0.65313 ×10^-11 （ｒ₆ 面）Ｐ＝0.9397，Ａ₄ ＝0.40635 ×10^-5 ，Ａ₆ ＝0.20012 ×10^-8 ，Ａ₈ ＝0.50181 ×10^-9 ，Ａ₁₀＝0.16818 ×10^-11 （ｒ₉ 面）Ｐ＝1.6594 ，Ａ₄ ＝-0.85593×10^-4 ，Ａ₆ ＝0.90250 ×10^-7 ，Ａ₈ ＝-0.23955×10^-7 ，Ａ₁₀＝0.25014 ×10^-9 ｆ 35 49.5 70 Ｄ 26.615 12.905 3.214 ｜ｆ₁|／ｆ_W ＝1.39 ，ｆ₂ ／ｆ_W ＝0.96 ， Δ_R2／φ_R2＝34.18 （ｙ＝5.853 ）ｒ₉ 面，ν₂₁＝96.47 ， Δ_F ／φ_F ＝6.48（ｙ＝13.263）ｒ₁ 面，ｆ_R1／ｆ₂ ＝0.83 実施例２ｆ＝35〜49.5〜70mm ，Ｆ／5.42〜Ｆ／6.49〜Ｆ／8.00 ２ω＝63.36 〜47.15 〜34.30 °，ｆ_B ＝44.4〜54.9〜69.7mm ｒ₁ ＝163.6670（非球面）ｄ₁ ＝1.7700 ｎ₁ ＝1.69500 ν₁ ＝42.16 ｒ₂ ＝16.9780 （非球面）ｄ₂ ＝6.7000 ｒ₃ ＝22.0480 ｄ₃ ＝3.0000 ｎ₂ ＝1.80518 ν₂ ＝25.43 ｒ₄ ＝31.9850 ｄ₄ ＝Ｄ（可変）ｒ₅ ＝∞（絞り）ｄ₅ ＝1.0000 ｒ₆ ＝11.9950 （非球面）ｄ₆ ＝10.3000 ｎ₃ ＝1.49700 ν₃ ＝81.61 ｒ₇ ＝-551.5680 ｄ₇ ＝2.3400 ｒ₈ ＝-55.1110（非球面）ｄ₈ ＝2.0000 ｎ₄ ＝1.76182 ν₄ ＝26.52 ｒ₉ ＝141.7500 非球面係数（ｒ₁ 面）Ｐ＝0.9951 ，Ａ₄ ＝0.43429 ×10^-5 ，Ａ₆ ＝-0.13506×10^-9 ，Ａ₈ ＝-0.29536×10^-10 （ｒ₂ 面）Ｐ＝1.1585 ，Ａ₄ ＝-0.56237×10^-5 ，Ａ₆ ＝0.38280 ×10^-7 ，Ａ₈ ＝-0.51975×10^-9 （ｒ₆ 面）Ｐ＝0.9465 ，Ａ₄ ＝0.23840 ×10^-5 ，Ａ₆ ＝0.56190 ×10^-7 ，Ａ₈ ＝0.15830 ×10^-8 ，Ａ₁₀＝0.71618 ×10^-11 （ｒ₈ 面）Ｐ＝1.6434 ，Ａ₄ ＝-0.12066×10^-3 ，Ａ₆ ＝-0.26085×10^-6 ，Ａ₈ ＝-0.39344×10^-7 ，Ａ₁₀＝0.43534 ×10^-9 ｆ 35 49.5 70 Ｄ 24.654 12.199 3.395 ｜ｆ₁|／ｆ_W ＝1.29 ，ｆ₂ ／ｆ_W ＝0.94 ， Δ_R2／φ_R2＝6.66（ｙ＝5.013 ）ｒ₈ 面，ν₂₁＝81.61 ， Δ_F ／φ_F ＝19.31 （ｙ＝12.233）ｒ₁ 面，0.24（ｙ＝10.390）ｒ₂ 面，ｆ_R1／ｆ₂ ＝0.72 実施例３ｆ＝35〜49.5〜70mm ，Ｆ／5.52〜Ｆ／6.54〜Ｆ／8.00 ２ω＝63.36 〜47.15 〜34.30 °，ｆ_B ＝45.6〜56.6〜72.2mm ｒ₁ ＝56.8690 ｄ₁ ＝1.7600 ｎ₁ ＝1.66672 ν₁ ＝48.32 ｒ₂ ＝14.0300 ｄ₂ ＝6.3500 ｒ₃ ＝25.4720 ｄ₃ ＝3.0300 ｎ₂ ＝1.80518 ν₂ ＝25.43 ｒ₄ ＝38.5240 （非球面）ｄ₄ ＝Ｄ（可変）ｒ₅ ＝∞（絞り）ｄ₅ ＝1.0000 ｒ₆ ＝16.2750 ｄ₆ ＝8.7600 ｎ₃ ＝1.56907 ν₃ ＝71.30 ｒ₇ ＝-17.2510 ｄ₇ ＝1.5000 ｎ₄ ＝1.59551 ν₄ ＝39.21 ｒ₈ ＝199.6540 ｄ₈ ＝6.1800 ｒ₉ ＝-50.7120（非球面）ｄ₉ ＝1.7600 ｎ₅ ＝1.63854 ν₅ ＝55.38 ｒ₁₀＝-71.0530 非球面係数（ｒ₄ 面）Ｐ＝1.0000 ，Ａ₄ ＝-0.13599×10^-4 ，Ａ₆ ＝-0.43293×10^-7 ，Ａ₈ ＝-0.18507×10^-9 （ｒ₉ 面）Ｐ＝1.6364 ，Ａ₄ ＝-0.62409×10^-4 ，Ａ₆ ＝-0.11008×10^-6 ，Ａ₈ ＝-0.94972×10^-8 ，Ａ₁₀＝0.88123 ×10^-10 ｆ 35 49.5 70 Ｄ 25.379 12.385 3.200 ｜ｆ₁|／ｆ_W ＝1.29 ，ｆ₂ ／ｆ_W ＝0.98 ， Δ_R2／φ_R2＝7.47（ｙ＝5.953 ）ｒ₉ 面，ν₂₁＝110.51 Δ_F ／φ_F ＝7.08（ｙ＝9.403 ）ｒ₄ 面，ｆ_R1／ｆ₂ ＝0.93 実施例４ｆ＝35〜56.1〜90mm ，Ｆ／5.6 〜Ｆ／7.25〜Ｆ／9.92 ，２ω＝63.36 〜42.12 〜26.99 °，ｆ_B ＝49.4〜67.1〜95.5mm ｒ₁ ＝215.0200 ｄ₁ ＝1.8300 ｎ₁ ＝1.80400 ν₁ ＝46.57 ｒ₂ ＝17.1590 （非球面）ｄ₂ ＝6.7700 ｒ₃ ＝27.0920 ｄ₃ ＝3.0000 ｎ₂ ＝1.76182 ν₂ ＝26.52 ｒ₄ ＝58.3920 ｄ₄ ＝Ｄ（可変）ｒ₅ ＝∞（絞り）ｄ₅ ＝1.0000 ｒ₆ ＝13.4650 （非球面）ｄ₆ ＝7.5200 ｎ₃ ＝1.56873 ν₃ ＝63.16 ｒ₇ ＝-17.6940 ｄ₇ ＝1.5000 ｎ₄ ＝1.63636 ν₄ ＝35.37 ｒ₈ ＝114.7790 ｄ₈ ＝4.7100 ｒ₉ ＝-45.6040（非球面）ｄ₉ ＝1.8800 ｎ₅ ＝1.77250 ν₅ ＝49.66 ｒ₁₀＝-127.6830 非球面係数（ｒ₂ 面）Ｐ＝1.2761 ，Ａ₄ ＝-0.19169×10^-4 ，Ａ₆ ＝-0.12866×10^-7 ，Ａ₈ ＝-0.52470×10^-9 （ｒ₆ 面）Ｐ＝0.9460 ，Ａ₄ ＝0.57808 ×10^-5 ，Ａ₆ ＝0.10384 ×10^-6 ，Ａ₈ ＝0.49381 ×10^-9 ，Ａ₁₀＝0.80171 ×10^-11 （ｒ₉ 面）Ｐ＝1.6587 ，Ａ₄ ＝-0.91883×10^-4 ，Ａ₆ ＝-0.44647×10^-6 ，Ａ₈ ＝-0.14988×10^-7 ，Ａ₁₀＝0.11064 ×10^-9 ｆ 35 56.1 90 Ｄ 27.720 11.696 1.685 ｜ｆ₁|／ｆ_W ＝1.21 ，ｆ₂ ／ｆ_W ＝1.01 ， Δ_R2／φ_R2＝4.90（ｙ＝5.204 ）ｒ₉ 面，ν₂₁＝98.53 ， Δ_F ／φ_F ＝3.61（ｙ＝10.296）ｒ₂ 面，ｆ_R1／ｆ₂ ＝0.81 実施例５ｆ＝28〜41〜60mm ，Ｆ／4.6 〜Ｆ／5.48〜Ｆ／6.78 ２ω＝75.30 〜55.56 〜39.60 °，ｆ_B ＝37.7〜46.5〜59.5mm ｒ₁ ＝122.7820（非球面）ｄ₁ ＝1.8000 ｎ₁ ＝1.70154 ν₁ ＝41.24 ｒ₂ ＝16.3020 （非球面）ｄ₂ ＝6.7800 ｒ₃ ＝22.2110 ｄ₃ ＝3.4000 ｎ₂ ＝1.80518 ν₂ ＝25.43 ｒ₄ ＝34.0820 ｄ₄ ＝Ｄ（可変）ｒ₅ ＝∞（絞り）ｄ₅ ＝1.0000 ｒ₆ ＝11.7020 （非球面）ｄ₆ ＝11.9900 ｎ₃ ＝1.49700 ν₃ ＝81.61 ｒ₇ ＝-141.3070 ｄ₇ ＝1.1200 ｒ₈ ＝-67.2250（非球面）ｄ₈ ＝1.7500 ｎ₄ ＝1.72151 ν₄ ＝29.24 ｒ₉ ＝54.9190 非球面係数（ｒ₁ 面）Ｐ＝0.9773 ，Ａ₄ ＝0.89503 ×10^-5 ，Ａ₆ ＝-0.22491×10^-7 ，Ａ₈ ＝0.22777 ×10^-10 （ｒ₂ 面）Ｐ＝0.8460 ，Ａ₄ ＝0.59062 ×10^-5 ，Ａ₆ ＝0.21591 ×10^-7 ，Ａ₈ ＝-0.22459×10^-9 （ｒ₆ 面）Ｐ＝1.2248 ，Ａ₄ ＝-0.26776×10^-4 ，Ａ₆ ＝0.16761 ×10^-6 ，Ａ₈ ＝-0.79024×10^-8 ，Ａ₁₀＝0.64742 ×10^-10 （ｒ₈ 面）Ｐ＝1.6355 ，Ａ₄ ＝-0.13223×10^-3 ，Ａ₆ ＝-0.11823×10^-5 ，Ａ₈ ＝0.30622 ×10^-8 ，Ａ₁₀＝-0.35826×10^-9 ｆ 28 41 60 Ｄ 34.863 17.308 5.335 ｜ｆ₁|／ｆ_W ＝1.70 ，ｆ₂ ／ｆ_W ＝1.16 ， Δ_R2／φ_R2＝12.30 （ｙ＝5.271 ）ｒ₈ 面，ν₂₁＝81.61 Δ_F ／φ_F ＝72.11 （ｙ＝17.791）ｒ₁ 面，9.50（ｙ＝13.905）ｒ₂ 面，ｆ_R1／ｆ₂ ＝0.69 実施例６ｆ＝28〜47.3〜80mm ，Ｆ／5 〜Ｆ／6.50〜Ｆ／9.05 ，２ω＝75.30 〜49.09 〜30.22 °，ｆ_B ＝40.1〜54.7〜79.4mm ｒ₁ ＝249.5410 ｄ₁ ＝2.0000 ｎ₁ ＝1.72000 ν₁ ＝43.70 ｒ₂ ＝15.6930 （非球面）ｄ₂ ＝6.8000 ｒ₃ ＝26.8560 ｄ₃ ＝3.5000 ｎ₂ ＝1.80518 ν₂ ＝25.43 ｒ₄ ＝57.2890 ｄ₄ ＝Ｄ（可変）ｒ₅ ＝∞（絞り）ｄ₅ ＝1.0000 ｒ₆ ＝10.7530 （非球面）ｄ₆ ＝9.9900 ｎ₃ ＝1.49700 ν₃ ＝81.61 ｒ₇ ＝-23.7700 ｄ₇ ＝2.0000 ｎ₄ ＝1.74950 ν₄ ＝35.27 ｒ₈ ＝-112.9100 ｄ₈ ＝1.0900 ｒ₉ ＝-44.6140（非球面）ｄ₉ ＝2.0000 ｎ₅ ＝1.71700 ν₅ ＝47.94 ｒ₁₀＝104.3130 非球面係数（ｒ₂ 面）Ｐ＝0.6617 ，Ａ₄ ＝-0.71044×10^-5 ，Ａ₆ ＝0.52999 ×10^-8 ，Ａ₈ ＝-0.14357×10^-9 （ｒ₆ 面）Ｐ＝1.2229 ，Ａ₄ ＝-0.23436×10^-4 ，Ａ₆ ＝-0.90880×10^-7 ，Ａ₈ ＝-0.12618×10^-8 ，Ａ₁₀＝-0.13681×10^-11 （ｒ₉ 面）Ｐ＝1.6353 ，Ａ₄ ＝-0.17152×10^-3 ，Ａ₆ ＝-0.10439×10^-5 ，Ａ₈ ＝-0.39303×10^-7 ｆ 28 47.3 80 Ｄ 36.490 14.605 1.627 ｜ｆ₁|／ｆ_W ＝1.59 ，ｆ₂ ／ｆ_W ＝1.20 ， Δ_R2／φ_R2＝8.21（ｙ＝4.938 ）ｒ₉ 面，ν₂₁＝116.88 ， Δ_F ／φ_F ＝30.64 （ｙ＝13.688）ｒ₂ 面，ｆ_R1／ｆ₂ ＝0.69 実施例７ｆ＝35〜49.5〜70mm ，Ｆ／5.4 〜Ｆ／6.48〜Ｆ／8.00 ，２ω＝63.36 〜47.15 〜34.30 °，ｆ_B ＝35.0〜43.9〜56.4mm ｒ₁ ＝464.3240 ｄ₁ ＝1.8200 ｎ₁ ＝1.83400 ν₁ ＝37.16 ｒ₂ ＝19.3530 （非球面）ｄ₂ ＝4.5100 ｒ₃ ＝25.8360 ｄ₃ ＝2.8900 ｎ₂ ＝1.78472 ν₂ ＝25.68 ｒ₄ ＝64.4360 ｄ₄ ＝Ｄ（可変）ｒ₅ ＝∞（絞り）ｄ₅ ＝1.0000 ｒ₆ ＝10.2900 （非球面）ｄ₆ ＝7.1200 ｎ₃ ＝1.56873 ν₃ ＝63.16 ｒ₇ ＝-13.4020 ｄ₇ ＝1.5000 ｎ₄ ＝1.72342 ν₄ ＝37.95 ｒ₈ ＝453.9560 ｄ₈ ＝5.2600 ｒ₉ ＝-19.6390（非球面）ｄ₉ ＝1.8000 ｎ₅ ＝1.72916 ν₅ ＝54.68 ｒ₁₀＝-75.2090（非球面）非球面係数（ｒ₂ 面）Ｐ＝1.2759 ，Ａ₄ ＝-0.85380×10^-5 ，Ａ₆ ＝-0.95837×10^-8 ，Ａ₈ ＝-0.17605×10^-9 （ｒ₆ 面）Ｐ＝0.4009 ，Ａ₄ ＝0.73404 ×10^-4 ，Ａ₆ ＝0.60455 ×10^-6 ，Ａ₈ ＝0.52059 ×10^-8 ，Ａ₁₀＝0.65724 ×10^-10 （ｒ₉ 面）Ｐ＝1.9469 ，Ａ₄ ＝-0.57999×10^-3 ，Ａ₆ ＝-0.41946×10^-5 ，Ａ₈ ＝0.81235 ×10^-7 ，Ａ₁₀＝-0.35585×10^-8 （ｒ₁₀面）Ｐ＝1.4468 ，Ａ₄ ＝-0.33489×10^-3 ，Ａ₆ ＝0.16171 ×10^-5 ，Ａ₈ ＝0.86077 ×10^-8 ｆ 35 49.5 70 Ｄ 25.089 12.004 2.755 ｜ｆ₁|／ｆ_W ＝1.44 ，ｆ₂ ／ｆ_W ＝0.88 ， Δ_R2／φ_R2＝10.83 （ｙ＝4.895 ）ｒ₉ 面，-28.98（ｙ＝5.659 ）ｒ₁₀面 ν₂₁＝101.11 ，Δ_F ／φ_F ＝1.21（ｙ＝10.315）ｒ₂ 面，ｆ_R1／ｆ₂ ＝0.71 実施例８ｆ＝28〜44.3〜70mm ，Ｆ／4.6 〜Ｆ／5.75〜Ｆ／7.56 ，２ω＝75.30 〜51.99 〜34.30 °，ｆ_B ＝35.0〜46.3〜64.0mm ｒ₁ ＝154.9070 ｄ₁ ＝1.8000 ｎ₁ ＝1.80440 ν₁ ＝39.58 ｒ₂ ＝15.7480 （非球面）ｄ₂ ＝5.0000 ｒ₃ ＝24.0530 ｄ₃ ＝4.2000 ｎ₂ ＝1.78472 ν₂ ＝25.68 ｒ₄ ＝61.3550 ｄ₄ ＝Ｄ（可変）ｒ₅ ＝∞（絞り）ｄ₅ ＝1.0000 ｒ₆ ＝13.4590 （非球面）ｄ₆ ＝5.9200 ｎ₃ ＝1.58913 ν₃ ＝61.18 ｒ₇ ＝-15.0400 ｄ₇ ＝1.5000 ｎ₄ ＝1.66680 ν₄ ＝33.04 ｒ₈ ＝-204.7310 ｄ₈ ＝6.6500 ｒ₉ ＝-38.7950（非球面）ｄ₉ ＝1.8000 ｎ₅ ＝1.67790 ν₅ ＝55.33 ｒ₁₀＝182.5170 非球面係数（ｒ₂ 面）Ｐ＝0.6337 ，Ａ₄ ＝-0.11938×10^-5 ，Ａ₆ ＝0.65110 ×10^-8 ，Ａ₈ ＝-0.86380×10^-10 （ｒ₆ 面）Ｐ＝0.9233 ，Ａ₄ ＝0.41782 ×10^-5 ，Ａ₆ ＝0.16006 ×10^-6 ，Ａ₈ ＝-0.23806×10^-8 ，Ａ₁₀＝0.36353 ×10^-10 （ｒ₉ 面）Ｐ＝19.6285 ，Ａ₄ ＝-0.87703×10^-4 ，Ａ₆ ＝-0.50475×10^-6 ，Ａ₈ ＝-0.99444×10^-8 ｆ 28 44.3 70 Ｄ 34.954 15.359 3.001 ｜ｆ₁|／ｆ_W ＝1.66 ，ｆ₂ ／ｆ_W ＝1.15 ， Δ_R2／φ_R2＝9.90（ｙ＝5.681 ）ｒ₉ 面，ν₂₁＝94.22 ， Δ_F ／φ_F ＝20.36 （ｙ＝13.483）ｒ₂ 面，ｆ_R1／ｆ₂ ＝0.74 ただしｒ₁ ，ｒ₂ ，・・・はレンズ各面の曲率半径、ｄ
₁ ，ｄ₂ ，・・・は各レンズの肉厚およびレンズ間隔、ｎ
₁ ，ｎ₂ ，・・・は各レンズの屈折率、ν₁ ，ν₂ ，・・・
は各レンズのアッベ数、ｆ_B はバックフォーカスであ
る。Embodiments Next, respective embodiments of the compact two-group zoom lens of the present invention will be shown. Example 1 f = 35 to 49.5 to 70 mm, F / 4.6 to F / 5.45 to F / 6.67 2ω = 63.36 to 47.15 to 34.30 °, f _B = 43.3 to 53.3 to 67.4 mm r ₁ = 83.3070 (aspherical surface) d ₁ = 1.8000 n ₁ = 1.72000 ν ₁ ＝ 46.03 r ₂ = 17.0980 d ₂ ＝ 6.3600 r ₃ ＝ 20.2750 d ₃ ＝ 3.0000 n ₂ ＝ 1.78472 ν ₂ ＝ 25.68 r ₄ ＝ 27.2690 d ₄ ＝ D (variable) r ₅ ＝ ∞ ( _{_{stop) d 5 = 1.0000 r 6 =}} 15.1410 ( _{_{aspherical) d 6 = 7.7700 n 3 =}} 1.58913 ν 3 = 61.18 r 7 = -16.6450 d 7 = 1.5000 n 4 = 1.59270 ν 4 = 35.29 r 8 = 150.1760 d 8 = 4.6600 r ₉ = -196.3710 (aspherical surface) d ₉ = 1.8000 n ₅ = 1.67790 ν ₅ = 50.72 r ₁₀ = 101.1350 aspherical surface coefficient (r ₁ surface) P = 0.9806, A ₄ = 0.12526 × 10 ^-5 , A ₆ = 0.19987 × 10 ^-8 , A ₈ = 0.65313 × 10 ^-11 (r ₆ surface) P = 0.9397, A ₄ = 0.40635 × 10 ^-5 , A ₆ = 0.20012 × 10 ^-8 , A ₈ = 0.50181 × 10 ^-9 , A ₁₀ = 0.16818 × 10 ^-11 (r ₉ surface) P = 1.6594, A ₄ = -0.85593 × 10 ^-4 , A ₆ = 0.90250 × 10 ^-7 , A ₈ = -0.23955 × 10 ^-7 , A ₁₀ = 0.25014 × 10 ^-9 f 35 49.5 70 D 26.615 12.905 3.214 | f ₁ | / f _W = 1.39, f ₂ / F _W = 0.96, Δ _R2 / φ _R2 = 34.18 (y = 5.853) r ₉ surface, ν ₂₁ = 96.47, Δ _F / φ _F = 6.48 (y = 13.263) r ₁ surface, f _R1 / f ₂ = 0.83 Example 2 f = 35 to 49.5 to 70 mm, F / 5.42 to F / 6.49 to F / 8.00 2ω = 63.36 to 47.15 to 34.30 °, f _B = 44.4 to 54.9 to 69.7 mm r ₁ = 163.6670 (aspherical surface) d ₁ = 1.7700 n ₁ = 1.69500 ν ₁ ＝ 42.16 r ₂ = 16.9780 (aspherical surface) d ₂ ＝ 6.7000 r ₃ ＝ 22.0480 d ₃ ＝ 3.0000 n ₂ = 1.80518 ν ₂ ＝ 25.43 r ₄ ＝ 31.9850 d ₄ ＝ D (variable) r ₅ = ∞ _{_{(stop) d 5 = 1.0000 r 6 =}} 11.9950 ( _{_{aspherical) d 6 = 10.3000 n 3 =}} 1.49700 ν 3 = 81.61 r 7 = -551.5680 d 7 = 2.3400 r 8 = -55.1110 ( aspherical) d ₈ = 2.0000 n ₄ = 1.76182 ν ₄ = 26.52 r ₉ = 141.7500 Aspheric coefficient (r ₁ surface) P = 0. 9951, A ₄ = 0.43429 × 10 ^-5 , A ₆ = -0.13506 × 10 ^-9 , A ₈ = -0.29536 × 10 ^-10 (r ₂ surface) P = 1.1585, A ₄ = -0.56237 × 10 ^-5 , A ₆ = 0.38280 × 10 ^-7 , A ₈ = -0.51975 × 10 ^-9 (r ₆ surface) P = 0.9465, A ₄ = 0.23840 × 10 ^-5 , A ₆ = 0.56190 × 10 ^-7 , A ₈ = 0.15830 × 10 ^-8 , A ₁₀ = 0.71618 × 10 ^-11 (r ₈ surface) P = 1.6434, A ₄ = -0.12066 × 10 ^-3 , A ₆ = -0.26085 × 10 ^-6 , A ₈ = -0.39344 × 10 ^-7 , A ₁₀ = 0.43534 × 10 ^-9 f 35 49.5 70 D 24.654 12.199 3.395 | f ₁ | / f _W = 1.29, f ₂ / f _W = 0.94, Δ _{R 2} / φ _{R 2} = 6.66 (y = 5.013) r ₈ surface, ν ₂₁ = 81.61, Δ _F / φ _F = 19.31 (y = 12.233) r ₁ surface, 0.24 (y = 10.390) r ₂ surface, f _R1 / f ₂ = 0.72 Example 3 f = 35 to 49.5 to 70 mm, F /5.52 to F / 6.54 to F / 8.00 2ω = 63.36 to 47.15 to 34.30 °, f _B = 45.6 to 56.6 to 72.2 mm r ₁ = 56.8690 d ₁ = 1.7600 n ₁ = 1.66672 ν ₁ = 48.32 r ₂ = 14.0300 d ₂ = 6 .3500 r ₃ = 25.4720 d ₃ = 3.0300 n ₂ = 1.80518 ν ₂ = 25.43 r ₄ = 38.5240 (aspherical surface) d ₄ = D (variable) r ₅ = ∞ (aperture) d ₅ = 1.0000 r ₆ = 16.2750 d ₆ _{_{= 8.7600 n 3 = 1.56907 ν 3}} = 71.30 r 7 = -17.2510 d 7 = 1.5000 n 4 = 1.59551 ν 4 = 39.21 r 8 = 199.6540 d 8 = 6.1800 r 9 = -50.7120 ( aspherical) d ₉ = 1.7600 n ₅ = 1.63854 ν ₅ = 55.38 r ₁₀ = -71.0530 Aspheric surface coefficient (r ₄ surface) P = 1.0000, A ₄ = -0.13599 × 10 ^-4 , A ₆ = -0.43293 × 10 ^-7 , A ₈ = -0.18507 × 10 ^-9 (r ₉ surface) P = 1.6364, A ₄ = -0.62409 x 10 ^-4 , A ₆ = -0.11008 x 10 ^-6 , A ₈ = -0.94972 x 10 ^-8 , A ₁₀ = 0.88123 x 10 ^-10 f 35 49.5 70 D 25.379 12.385 3.200 | f ₁ | / f _W = 1.29, f ₂ / f _W = 0.98, Δ _R2 / φ _R2 = 7.47 (y = 5.953) r ₉ surface, ν ₂₁ = 110.51 Δ _F / φ _F = 7.08 (y = 9.403) r ₄ faces, f _R1 / f ₂ = 0.93 Example 4 f = 35 to 56.1 to 90 mm, F / 5.6 to F / 7.25 ~ F / 9.92, 2ω = 63.36 ~ 42.12 ~ 26.99 °, f _B = 49.4 ~ 67.1 ~ 95.5 mm r ₁ = 215.0200 d ₁ = 1.8300 n ₁ = 1.80400 ν ₁ = 46.57 r ₂ = 17.1590 (aspherical surface) d ₂ = 6.7700 r ₃ = 27.0920 d ₃ = 3.0000 n ₂ = 1.76182 ν ₂ = 26.52 r ₄ = 58.3920 d ₄ = D (variable) r ₅ = ∞ (aperture) d ₅ = 1.0000 r ₆ = 13.4650 (aspherical surface) d ₆ = _{_{7.5200 n 3 = 1.56873 ν 3 =}} 63.16 r 7 = -17.6940 d 7 = 1.5000 n 4 = 1.63636 ν 4 = 35.37 r 8 = 114.7790 d 8 = 4.7100 r 9 = -45.6040 ( aspherical) d ₉ = 1.8800 n ₅ = 1.77250 ν ₅ = 49.66 r ₁₀ = -127.6830 Aspheric coefficient (r ₂ surface) P = 1.2761, A ₄ = -0.19169 × 10 ⁻⁴ , A ₆ = −0.12866 × 10 ⁻⁷ , A ₈ = −0.52470 × 10 ^{− 9} (r ₆ surface) P = 0.9460, A ₄ = 0.57808 × 10 ^-5 , A ₆ = 0.10384 × 10 ^-6 , A ₈ = 0.49381 × 10 ^-9 , A ₁₀ = 0.80171 × 10 ^-11 (r ₉ surface) _{P = 1.6587, A 4 = -0.91883} × 10 -4, A 6 = -0.44647 × 10 -6, A 8 = -0.14988 × 1 0 ^-7 , A ₁₀ = 0.11064 × 10 ^-9 f 35 56.1 90 D 27.720 11.696 1.685 ｜ f ₁ | / f _W = 1.21, f ₂ / f _W = 1.01, Δ _{R 2} / φ _{R 2} = 4.90 (y = 5.204) r ₉ surface, ν ₂₁ = 98.53, Δ _F / φ _F = 3.61 (y = 10.296) r ₂ surface, f _R1 / f ₂ = 0.81 Example 5 f = 28 to 41 to 60 mm, F / 4.6 to F / 5.48 ~F / 6.78 2ω = 75.30 ~55.56 ~39.60 °, f B = 37.7~46.5~59.5mm r 1 = 122.7820 ( _{_{aspherical) d 1 = 1.8000 n 1 =}} 1.70154 ν 1 = 41.24 r 2 = 16.3020 ( aspherical) d ₂ = 6.7800 r ₃ = 22.2110 d ₃ = 3.4000 n ₂ = 1.80518 ν ₂ = 25.43 r ₄ = 34.0820 d ₄ = D (variable) r ₅ = ∞ (aperture) d ₅ = 1.0000 r ₆ = 11.7020 (aspherical surface) _{_{d 6 = 11.9900 n 3 = 1.49700}} ν 3 = 81.61 r 7 = -141.3070 d 7 = 1.1200 r 8 = -67.2250 ( _{_{aspherical) d 8 = 1.7500 n 4 =}} 1.72151 ν 4 = 29.24 r 9 = 54.9190 aspheric coefficients ( r ₁ _{surface) P = 0.9773, A 4 =} 0.89503 × 10 -5, A 6 = -0.22491 × 10 - ⁷ , A ₈ = 0.22777 × 10 ^-10 (r ₂ surface) P = 0.8460, A ₄ = 0.59062 × 10 ^-5 , A ₆ = 0.21591 × 10 ^-7 , A ₈ = -0.22459 × 10 ^-9 (r ₆ surface) _{) P = 1.2248, A 4 =} -0.26776 × 10 -4, A 6 = 0.16761 × 10 -6, A 8 = -0.79024 × 10 -8, A 10 = 0.64742 × 10 -10 (r 8 side) P = 1.6355 , A ₄ = -0.13223 x 10 ^-3 , A ₆ = -0.11823 x 10 ^-5 , A ₈ = 0.30622 x 10 ^-8 , A ₁₀ = -0.35826 x 10 ^-9 f 28 41 60 D 34.863 17.308 5.335 | f ₁ | / F _W = 1.70, f ₂ / f _W = 1.16, Δ _R2 / φ _R2 = 12.30 (y = 5.271) r ₈ faces, ν ₂₁ = 81.61 Δ _F / φ _F = 72.11 (y = 17.791) r ₁ face , 9.50 (y = 13.905) r ₂ surface, f _R1 / f ₂ = 0.69, Example 6 f = 28 to 47.3 to 80 mm, F / 5 to F / 6.50 to F / 9.05, 2ω = 75.30 to 49.09 to 30.22 °, _{_{f B = 40.1~54.7~79.4mm r 1 = 249.5410}} d 1 = 2.0000 n 1 = 1.72000 ν 1 = 43.70 r 2 = 15.6930 ( _{_{aspherical) d 2 = 6.8000 r 3 =}} 26.8560 d 3 = 3.5000 n 2 _{_{1.80518 ν 2 = 25.43 r 4 =}} 57.2890 d 4 = D ( variable) r ₅ = ∞ _{_{(stop) d 5 = 1.0000 r 6 =}} 10.7530 ( _{_{aspherical) d 6 = 9.9900 n 3 =}} 1.49700 ν 3 = 81.61 r 7 = _{_{-23.7700 d 7 = 2.0000 n 4 =}} 1.74950 ν 4 = 35.27 r 8 = -112.9100 d 8 = 1.0900 r 9 = -44.6140 ( _{_{aspherical) d 9 = 2.0000 n 5 =}} 1.71700 ν 5 = 47.94 r 10 = 104.3130 aspherical Coefficient (r ₂ surface) P = 0.6617, A ₄ = -0.71044 × 10 ^-5 , A ₆ = 0.52999 × 10 ^-8 , A ₈ = -0.14357 × 10 ^-9 (r ₆ surface) P = 1.2229, A ₄ = -0.23436 × 10 ^-4 , A ₆ = -0.90880 × 10 ^-7 , A ₈ = -0.12618 × 10 ^-8 , A ₁₀ = -0.13681 × 10 ^-11 (r ₉ surface) P = 1.6353, A ₄ = -0.17152 × 10 ^-3 , A ₆ = -0.10439 × 10 ^-5 , A ₈ = -0.39303 × 10 ^-7 f 28 47.3 80 D 36.490 14.605 1.627 ｜ f ₁ | / f _W = 1.59, f ₂ / f _W = 1.20, Δ _R2 / φ _R2 = 8.21 (y = 4.938) r ₉ faces, ν ₂₁ = 116.88, Δ _F / φ _F = 30.64 (y = 13.688) r ₂ faces, f _R1 / f ₂ = 0.69 Example 7 f = 35 to 49.5 to 70 mm, F / 5.4 to F / 6.48 to F / 8.00, 2ω = 63.36 to 47.15 to 34.30 °, f _B = 35.0 to 43.9 to 56.4 mm r ₁ = 464.3240 d ₁ _{_{= 1.8200 n 1 = 1.83400 ν 1}} = 37.16 r 2 = 19.3530 ( _{_{aspherical) d 2 = 4.5100 r 3 =}} 25.8360 d 3 = 2.8900 n 2 = 1.78472 ν 2 = 25.68 r 4 = 64.4360 d 4 = D ( variable) r ₅ = ∞ _{_{(stop) d 5 = 1.0000 r 6 =}} 10.2900 ( _{_{aspherical) d 6 = 7.1200 n 3 =}} 1.56873 ν 3 = 63.16 r 7 = -13.4020 d 7 = 1.5000 n 4 = 1.72342 ν 4 = 37.95 r 8 = 453.9560 d ₈ = 5.2600 r ₉ = -19.6390 (aspherical surface) d ₉ = 1.8000 n ₅ = 1.72916 ν ₅ = 54.68 r ₁₀ = -75.2090 (aspherical surface) aspherical coefficient (r ₂ surface) P = 1.2759, A ₄ = -0.85380 x 10 ^-5 , A ₆ = -0.95837 x 10 ^-8 , A ₈ = -0.17605 x 10 ^-9 (r ₆ surface) P = 0.4009, A ₄ = 0.73404 x 10 ^-4 , A ₆ = 0.60455 x 10 ^-6 , A ₈ = 0.52059 × 10 ^-8 , A ₁₀ = 0.65724 × 10 ^-10 (r ₉ surface) P = 1.9469, A ₄ = -0.57999 x 10 ^-3 , A ₆ = -0.41946 x 10 ^-5 , A ₈ = 0.81235 x 10 ^-7 , A ₁₀ = -0.35585 x 10 ^-8 (r ₁₀ plane) P = 1.4468, A ₄ = -0.33489 x 10 ^-3 , A ₆ = 0.16171 x 10 ^-5 , A ₈ = 0.86077 x 10 ^-8 f 35 49.5 70 D 25.089 12.004 2.755 | f ₁ | / f _W = 1.44, f ₂ / f _W = 0.88, Δ _R2 / φ _R2 = 10.83 (y = 4.895) r ₉ faces, -28.98 (y = 5.659) r ₁₀ faces ν ₂₁ = 101.11, Δ _F / φ _F = 1.21 (y = 10.315) r ₂ faces, f _R1 / f ₂ = 0.71 example 8 f = 28~44.3~70mm, F / 4.6 ~F / 5.75~F / 7.56, 2ω = 75.30 ~51.99 ~34.30 °, f B = 35.0~46.3~64.0mm r 1 = 154.9070 d ₁ = 1.8000 n ₁ = 1.80440 ν ₁ ＝ 39.58 r ₂ = 15.7480 (aspherical surface) d ₂ ＝ 5.0000 r ₃ ＝ 24.0530 d ₃ ＝ 4.2000 n ₂ ＝ 1.78472 ν ₂ ＝ 25.68 r ₄ ＝ 61.3550 d ₄ ＝ D ( variable) r ₅ = ∞ _{_{(stop) d 5 = 1.0000 r 6 =}} 13.4590 ( _{_{aspherical) d 6 = 5.9200 n 3 =}} 1.58913 ν 3 = 61.18 _{_{7 = -15.0400 d 7 = 1.5000 n}} 4 = 1.66680 ν 4 = 33.04 r 8 = -204.7310 d 8 = 6.6500 r 9 = -38.7950 ( _{_{aspherical) d 9 = 1.8000 n 5 =}} 1.67790 ν 5 = 55.33 r 10 = 182.5170 Aspherical surface coefficient (r ₂ surface) P = 0.6337, A ₄ = -0.11938 × 10 ^-5 , A ₆ = 0.65110 × 10 ^-8 , A ₈ = -0.86380 × 10 ^-10 (r ₆ surface) P = 0.9233, A ₄ = 0.41782 × 10 ^-5 , A ₆ = 0.16006 × 10 ^-6 , A ₈ = -0.23806 × 10 ^-8 , A ₁₀ = 0.36353 × 10 ^-10 (r ₉ surface) P = 19.6285, A ₄ = -0.87703 × 10 ^-4 , A ₆ = -0.50475 × 10 ^-6 , A ₈ = -0.99444 × 10 ^-8 f 28 44.3 70 D 34.954 15.359 3.001 | f ₁ | / f _W = 1.66, f ₂ / f _W = 1.15, Δ _{_{R2 / φ R2 = 9.90 (y}} = 5.681) r 9 _{_{side, ν 21 = 94.22, Δ F}} / φ F = 20.36 (y = 13.483) r 2 surface, f _R1 / f ₂ = 0.74 However r _1, r _2, ... is the radius of curvature of each lens surface, d
₁ , d ₂ , ... Is the thickness of each lens and the lens interval, n
₁ , n ₂ , ... Are the refractive indices of the respective lenses, ν ₁ , ν ₂ ,.
Is the Abbe number of each lens, and f _B is the back focus.

【００２３】いずれの実施例も、前群は物体側より順に
負レンズと正レンズの２群２枚にて構成され、１面ない
し２面の非球面を有している。一方、後群は既に記載の
通り正レンズ成分と負レンズ成分から構成されている
が、正レンズ成分は単レンズの場合と接合レンズの場合
との２通りあり、又負レンズ成分は、全て単レンズであ
る。従って、後群は２群２枚、又は、２群３枚にて構成
され１面ないし３面の非球面を有している。In any of the embodiments, the front lens group is composed of two negative lens elements and two positive lens elements in order from the object side, and has one or two aspherical surfaces. On the other hand, the rear lens group is composed of a positive lens component and a negative lens component as already described, but there are two types of positive lens components, that is, a single lens and a cemented lens, and all the negative lens components are single lenses. It is a lens. Therefore, the rear group is composed of two lenses in two groups or three lenses in two groups and has one to three aspherical surfaces.

【００２４】なお、接合レンズの場合、正レンズと負レ
ンズをわずか離した構成にしても問題はない。In the case of the cemented lens, there is no problem even if the positive lens and the negative lens are slightly separated.

【００２５】実施例は全てガラス材料を使用している
が、実施例３のように、後群中の負レンズ成分の屈折力
が弱い場合には、温度，湿度変化の影響を余り強く受け
ないので、プラスチック材料を利用することが可能であ
る。Although all the examples use glass materials, when the negative lens component in the rear lens group has a weak refracting power as in the example 3, it is not so strongly affected by changes in temperature and humidity. So it is possible to utilize plastic materials.

【００２６】実施例中の非球面の形状は、光軸上、光の
進行方向にＺ軸、光軸と直交する方向にＹ軸をとったと
き、以下の式で表わされる。 The shape of the aspherical surface in the embodiment is expressed by the following formula when the Z axis is in the light traveling direction and the Y axis is in the direction orthogonal to the optical axis on the optical axis.

【００２７】但し、ｒは近軸曲率半径、Ｐ，Ａ₄ ，Ａ
₆ ，Ａ₈ ，Ａ₁₀は非球面係数である。However, r is a paraxial radius of curvature, P, A ₄ , A
₆ , A ₈ and A ₁₀ are aspherical coefficients.

【００２８】又、実施例中、条件（３）と条件（５）の
数値において、Ｙは非球面量Δを計算するときの有効半
径を示す。In the examples, in the numerical values of condition (3) and condition (5), Y represents the effective radius when the aspherical surface amount Δ is calculated.

【００２９】[0029]

【発明の効果】本発明は前記構成をとることによって、
負，正の２群ズームタイプにおいて、少ないレンズ枚数
にもかかわらず、コンパクトで高性能なズームレンズが
得られた。According to the present invention, by adopting the above constitution,
In the negative and positive two-group zoom type, a compact and high-performance zoom lens was obtained despite the small number of lenses.

[Brief description of drawings]

【図１】実施例１の断面図FIG. 1 is a sectional view of a first embodiment.

【図２】実施例２の断面図FIG. 2 is a sectional view of a second embodiment.

【図３】実施例３の断面図FIG. 3 is a sectional view of a third embodiment.

【図４】実施例４の断面図FIG. 4 is a cross-sectional view of Example 4.

【図５】実施例５の断面図FIG. 5 is a sectional view of the fifth embodiment.

【図６】実施例６の断面図FIG. 6 is a sectional view of Example 6.

【図７】実施例７の断面図FIG. 7 is a sectional view of Example 7.

【図８】実施例８の断面図FIG. 8 is a sectional view of Example 8.

【図９】実施例１の広角端における収差曲線図FIG. 9 is an aberration curve diagram of Example 1 at the wide-angle end.

【図１０】実施例１の中間焦点距離における収差曲線
図FIG. 10 is an aberration curve diagram for Example 1 at an intermediate focal length.

【図１１】実施例１の望遠端における収差曲線図FIG. 11 is an aberration curve diagram of Example 1 at the telephoto end.

【図１２】実施例２の広角端における収差曲線図FIG. 12 is an aberration curve diagram for Example 2 at the wide-angle end.

【図１３】実施例２の中間焦点距離における収差曲線
図FIG. 13 is an aberration curve diagram for Example 2 at an intermediate focal length.

【図１４】実施例２の望遠端における収差曲線図14 is an aberration curve diagram for Example 2 at the telephoto end. FIG.

【図１５】実施例３の広角端における収差曲線図FIG. 15 is an aberration curve diagram for Example 3 at the wide-angle end.

【図１６】実施例３の中間焦点距離における収差曲線
図FIG. 16 is an aberration curve diagram for Example 3 at the intermediate focal length.

【図１７】実施例３の望遠端における収差曲線図FIG. 17 is an aberration curve diagram for Example 3 at the telephoto end.

【図１８】実施例４の広角端における収差曲線図FIG. 18 is an aberration curve diagram for Example 4 at the wide-angle end.

【図１９】実施例４の中間焦点距離における収差曲線
図FIG. 19 is an aberration curve diagram at the intermediate focal length of Example 4.

【図２０】実施例４の望遠端における収差曲線図20 is an aberration curve diagram for Example 4 at the telephoto end. FIG.

【図２１】実施例５の広角端における収差曲線図FIG. 21 is an aberration curve diagram for Example 5 at the wide-angle end.

【図２２】実施例５の中間焦点距離における収差曲線
図22 is an aberration curve diagram for Example 5 at the intermediate focal length. FIG.

【図２３】実施例５の望遠端における収差曲線図23 is an aberration curve diagram for Example 5 at the telephoto end. FIG.

【図２４】実施例６の広角端における収差曲線図FIG. 24 is an aberration curve diagram for Example 6 at the wide-angle end.

【図２５】実施例６の中間焦点距離における収差曲線
図FIG. 25 is an aberration curve diagram for Example 6 at the intermediate focal length.

【図２６】実施例６の望遠端における収差曲線図FIG. 26 is an aberration curve diagram for Example 6 at the telephoto end.

【図２７】実施例７の広角端における収差曲線図FIG. 27 is an aberration curve diagram of Example 7 at the wide-angle end.

【図２８】実施例７の中間焦点距離における収差曲線
図28 is an aberration curve diagram for Example 7 at the intermediate focal length. FIG.

【図２９】実施例７の望遠端における収差曲線図FIG. 29 is an aberration curve diagram for Example 7 at the telephoto end.

【図３０】実施例８の広角端における収差曲線図FIG. 30 is an aberration curve diagram for Example 8 at the wide-angle end.

【図３１】実施例８の中間焦点距離における収差曲線
図FIG. 31 is an aberration curve diagram for Example 8 at the intermediate focal length.

【図３２】実施例８の望遠端における収差曲線図FIG. 32 is an aberration curve diagram for Example 8 at the telephoto end.

Claims

[Claims]

1. A zoom lens comprising a front group having a negative refracting power and a rear group having a positive refracting power, in which zooming is performed by changing an interval between the two groups, wherein the rear group is a positive lens in order from the object side. A small two-group zoom lens including a negative lens component and a negative lens component, the negative lens component having at least one aspherical surface.

2. A compact two-group zoom lens according to claim 1, wherein the following conditions (1) and (2) are satisfied. (1) 1 <| f ₁ | / f _W <2 (2) 0.7 <f ₂ / f _W <1.4 where f ₁ and f ₂ are the focal lengths of the front group and the rear group, respectively.
_W is the focal length of the entire system at the wide-angle end.

3. At least one aspherical surface satisfies the following condition (3).
The compact two-group zoom lens according to claim 2, wherein (3) 0 <Δ _R2 / φ _{R2 where} Δ _R2 is the aspherical amount in the effective radius of the aspherical surface provided in the negative lens component in the rear group, and φ _R2 is the paraxial radius of curvature of the aspherical surface. _R2 is the value given by the following formula, where n _R2 and n ′ _R2 are the refractive indices of the media before and after the aspherical surface, respectively. φ _R2 = (n ' _R2- n _R2 ) / r _R2