JP7443018B2 - Zoom lens and optical equipment including it - Google Patents
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Description
本発明は、ズームレンズ及びそれを有する光学機器に関する。 The present invention relates to a zoom lens and an optical device including the zoom lens.
近年、固体撮像素子を用いた一眼レフカメラ等は仕様の多様化が進んでおり、アマチュア層向けに低価格なズームレンズの開発が必要となっている。 In recent years, the specifications of single-lens reflex cameras and the like that use solid-state image sensors have become increasingly diverse, and there is a need to develop low-cost zoom lenses for amateurs.
また、カメラにおいてはクイックリターンミラーがない、いわゆるミラーレスカメラが増えている。このミラーレスカメラは、本体が薄く、小型かつ軽量であることが特徴であるため、ミラーレスカメラにマッチした小型かつ軽量の交換レンズの開発が求められている。 Additionally, so-called mirrorless cameras, which do not have quick return mirrors, are on the rise. Mirrorless cameras are characterized by their thin, compact, and lightweight bodies, so there is a need to develop compact and lightweight interchangeable lenses that match mirrorless cameras.
このミラーレスカメラは、クイックリターンミラーのスペースが不要となるため、従来の交換レンズほどバックフォーカスを確保する必要がなく、小型かつ軽量のレンズを設計することが可能となる。 This mirrorless camera does not require space for a quick return mirror, so there is no need to ensure back focus as much as with conventional interchangeable lenses, making it possible to design a compact and lightweight lens.
特に望遠レンズは、バックフォーカスが長くなり易いが、望遠ズームレンズの広角端のバックフォーカスが短くなる構成とすることで、ミラーレスカメラ用の交換レンズとしての望遠レンズは小型化が可能となる。 In particular, telephoto lenses tend to have a long back focus, but by configuring a telephoto zoom lens to have a short back focus at the wide-angle end, it is possible to downsize the telephoto lens as an interchangeable lens for a mirrorless camera.
従来より、物体側から像側へ順に、正の屈折力を有する第１レンズ群と、負の屈折力を有する第２レンズ群と、複数のレンズ群とを有したズームレンズが知られている。このズームレンズでは、第１レンズ群を繰り出す、あるいは第２レンズ群を像側に移動させることによって主変倍とし、像側に配置された複数のレンズ群を移動させることで高倍率化、高性能化を行っている。 Conventionally, zoom lenses have been known that have, in order from the object side to the image side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, and a plurality of lens groups. . In this zoom lens, main magnification is achieved by extending the first lens group or moving the second lens group toward the image side, and by moving multiple lens groups placed on the image side, high magnification and We are improving performance.
また近年では、画像処理技術の進歩により、一部の収差を電気的に補正することが可能となっている。特に、色収差や歪曲収差といった諸収差を電気的に補正し、その他の収差補正に適した構成とすることで小型化や高画質化、コストダウンを行うことが可能となる。 Furthermore, in recent years, advances in image processing technology have made it possible to electrically correct some aberrations. In particular, by electrically correcting various aberrations such as chromatic aberration and distortion, and creating a configuration suitable for correcting other aberrations, it becomes possible to achieve downsizing, high image quality, and cost reduction.
上記従来のズームレンズの例として、例えば特許文献１が提案されている。このズームレンズは、各群の構成を簡素化することで小型化を実現している。しかし、ズーム全域の色収差は必ずしも十分に補正できているとは言えない状況であった。 As an example of the above-mentioned conventional zoom lens, for example, Patent Document 1 has been proposed. This zoom lens achieves miniaturization by simplifying the configuration of each group. However, it cannot be said that chromatic aberration over the entire zoom range is necessarily sufficiently corrected.
また、上記従来のズームレンズの他の例として、例えば特許文献２が提案されている。このズームレンズは４群構成とし、レンズ全長の小型化を特徴としている。しかし、望遠側の球面収差が十分補正されていないため光学性能という点では必ずしも十分とは言えない状況であった。 Moreover, as another example of the above-mentioned conventional zoom lens, for example, Patent Document 2 has been proposed. This zoom lens has a four-group structure and is characterized by a compact overall lens length. However, since the spherical aberration on the telephoto side is not sufficiently corrected, the optical performance cannot necessarily be said to be sufficient.
そこで、本発明は、上記課題を解決するため、ショートバックに対応し、安価でズーム全域で光学性能が良好なズームレンズおよびそれを有する光学機器の提供を目的とする。 SUMMARY OF THE INVENTION In order to solve the above problems, the present invention aims to provide a zoom lens that is compatible with short backs, is inexpensive, and has good optical performance over the entire zoom range, and an optical device having the same.
本発明の一側面としてのズームレンズは、物体側より像側へ順に配置された、正の屈折力を有する第１レンズ群と、負の屈折力を有する第２レンズ群と、複数のレンズ群を含む後続群とからなり、ズーミングに際して隣り合うレンズ群の間隔が変化するズームレンズであって、前記第１レンズ群は、前記物体側から前記像側へ順に、１枚の負レンズと１枚の正レンズから構成され、前記後続群のうち、最も像側に配置されたレンズ群Ｒｎは負の屈折力を有し、前記第１レンズ群に含まれる前記負レンズの異常分散性をΔθｇＦ１ｎ、前記負レンズのアッベ数および部分分散比を各々νｄ１ｎ、θｇＦ１ｎ、前記第１レンズ群の最も物体側のレンズ面の曲率、および最も像側のレンズ面の曲率を各々Ｒ１ｏｂｊ、Ｒ１ｉｍｇ、広角端および望遠端のバックフォーカスを各々ＢＦｗ、ＢＦｔ、前記レンズ群Ｒｎの焦点距離をｆＲｎ、前記第１レンズ群の焦点距離をｆ１としたとき、
ΔθｇＦ１ｎ＜０
ΔθｇＦ１ｎ＝θｇＦ１ｎ－（－１．６６５×１０
－７ ×νｄ１ｎ ３ ＋５．２１３×１０
－５ ×νｄ１ｎ ２ －５．６５６×１０
－３ ×νｄ１ｎ＋０．７２６８）
－０．９＜（Ｒ１ｏｂｊ＋Ｒ１ｉｍｇ）／（Ｒ１ｏｂｊ－Ｒ１ｉｍｇ）＜０
２．３＜ＢＦｔ／ＢＦｗ＜４．５
－１．２０＜ｆＲｎ／ｆ１＜－０．４５
なる条件式を満足することを特徴とする。
A zoom lens according to an aspect of the present invention includes a first lens group having a positive refractive power, a second lens group having a negative refractive power, and a plurality of lens groups arranged in order from the object side to the image side. The first lens group includes one negative lens and one negative lens in order from the object side to the image side. Among the subsequent groups, the lens group Rn disposed closest to the image side has a negative refractive power, and the anomalous dispersion of the negative lens included in the first lens group is expressed as Δθg F 1n, the Abbe number and partial dispersion ratio of the negative lens are respectively νd1n and θg F 1n, the curvature of the lens surface closest to the object side of the first lens group, and the curvature of the lens surface closest to the image side are respectively R1obj, R1img, When the back focus at the wide-angle end and the telephoto end are respectively BFw and BFt, the focal length of the lens group Rn is fRn, and the focal length of the first lens group is f1,
Δθg F 1n<0
Δθg F 1n=θg F 1n-(-1.665 ×10 -7 ×νd1n 3 +5.213 ×10 -5 ×νd1n 2 -5.656 ×10 -3 ×νd1n+0.7268)
-0.9<(R1obj+R1img)/(R1obj-R1img)<0
2.3<BFt/BFw<4.5
-1.20<fRn/f1<-0.45
It is characterized by satisfying the following conditional expression.
本発明の他の目的及び特徴は、以下の実施形態において説明される。 Other objects and features of the invention are explained in the following embodiments.
本発明によれば、ショートバックに対応し、安価でズーム全域で光学性能が良好なズームレンズおよびそれを有する光学機器が得られる。 According to the present invention, it is possible to obtain a zoom lens that is compatible with short backs, is inexpensive, and has good optical performance over the entire zoom range, and an optical device having the same.
以下、本発明の実施形態について、図面を参照しながら詳細に説明する。 Embodiments of the present invention will be described in detail below with reference to the drawings.
本発明のズームレンズは、ショートバックに対応し、安価でズーム全域で光学性能が良好なズームレンズであることが特徴である。本発明のズームレンズは、望遠系のズームレンズである。そのため、レンズ全体の価格のうち、レンズ外径が大きい第１レンズ群が占める割合が大きい。よって、本発明のズームレンズは、第１レンズ群を負レンズと正レンズの２枚構成としている。従来の望遠系のズームレンズとしては、第１レンズ群が３枚構成のものが知られている。２枚構成とすることで望遠側の諸収差、特に色収差、球面収差、コマ収差の発生が問題となってしまう。そのため、第１レンズ群の硝材および形状を適切に設定する必要がある。 The zoom lens of the present invention is characterized by being compatible with short backs, being inexpensive, and having good optical performance over the entire zoom range. The zoom lens of the present invention is a telephoto zoom lens. Therefore, the first lens group, which has a large lens outer diameter, accounts for a large proportion of the price of the entire lens. Therefore, in the zoom lens of the present invention, the first lens group is composed of two lenses, a negative lens and a positive lens. As a conventional telephoto zoom lens, one in which the first lens group is composed of three lenses is known. With a two-element configuration, various aberrations on the telephoto side, especially chromatic aberration, spherical aberration, and coma aberration, become a problem. Therefore, it is necessary to appropriately set the glass material and shape of the first lens group.
そこで、本発明のズームレンズは、第１レンズ群の負レンズに部分分散比の小さい低分散材料を使用している。低分散材料を使用することで、望遠側の２次の色消しが容易となる。この結果、従来３枚構成で軸上色収差を補正していたが、軸上色収差を２枚構成で補正することが可能となる。 Therefore, in the zoom lens of the present invention, a low dispersion material with a small partial dispersion ratio is used for the negative lens of the first lens group. By using a low-dispersion material, secondary achromatization on the telephoto side becomes easy. As a result, axial chromatic aberration has conventionally been corrected with a three-element structure, but it becomes possible to correct longitudinal chromatic aberration with a two-element structure.
第１レンズ群で軸上色収差の補正を行うと、変倍時に第１レンズ群が移動する。このため、第１レンズ群を通過する軸外光線の位置が変化し、変倍による倍率色収差変化が悪化する。そのため、軸外光線のレンズ群中の通過位置が高い最も像側のレンズ群で変倍による倍率色収差変動を補正している。 When axial chromatic aberration is corrected in the first lens group, the first lens group moves during zooming. For this reason, the position of off-axis rays passing through the first lens group changes, worsening changes in chromatic aberration of magnification due to zooming. Therefore, the variation in chromatic aberration of magnification due to zooming is corrected in the lens group closest to the image side, where the off-axis rays pass through the lens group.
特に最も像側のレンズ群を変倍時に大きく物体側へ繰り出すことで、軸外光線のレンズ群中の通過位置が大きく変化する。この変倍による軸外光線のレンズ群中の通過位置の差を利用して倍率色収差の変動を良好に補正している。 In particular, when the lens group closest to the image side is moved largely toward the object side during zooming, the passage position of off-axis rays in the lens group changes significantly. Fluctuations in chromatic aberration of magnification are effectively corrected by utilizing the difference in the passing position of off-axis rays in the lens groups due to this zooming.
一方、球面収差やコマ収差は、一般的に高屈折率の硝種を使用することで補正が容易となるが、色収差が悪化する。本発明のズームレンズでは、第１レンズ群のレンズ形状を規定することで各収差の発生を抑えるようにしている。つまり、第１レンズ群の最も物体側のレンズ面の曲率よりも最も像側のレンズ面の曲率を緩くし、第１レンズ群全体として両凸形状となる様にしている。この様にすることで、第２レンズ群で発生する球面収差やコマ収差を良好に補正することが可能となる。 On the other hand, spherical aberration and comatic aberration can generally be easily corrected by using a glass type with a high refractive index, but chromatic aberration worsens. In the zoom lens of the present invention, the occurrence of each aberration is suppressed by specifying the lens shape of the first lens group. That is, the curvature of the lens surface closest to the image side of the first lens group is made gentler than the curvature of the lens surface closest to the object side, so that the first lens group as a whole has a biconvex shape. By doing so, it becomes possible to satisfactorily correct spherical aberration and coma aberration occurring in the second lens group.
本発明のズームレンズは、上記レンズ構成とすることで諸収差の悪化を抑えつつ、ショートバックに対応した安価なズームレンズを達成している。 By adopting the above lens configuration, the zoom lens of the present invention achieves an inexpensive zoom lens compatible with short back while suppressing deterioration of various aberrations.
具体的には、本発明のズームレンズは、物体側より像側へ順に配置された、正の屈折力を有する第１レンズ群と、負の屈折力を有する第２レンズ群と、を有し、ズーミングに際して隣り合うレンズ群の間隔が変化するズームレンズである。第１レンズ群は、物体側から像側へ順に、１枚の負レンズと１枚の正レンズから構成される。第１レンズ群に含まれる負レンズの異常分散性をΔθｇｆ１ｎ、該負レンズのアッベ数および部分分散比を各々νｄ１ｎ、θｇｆ１ｎ、第１レンズ群の最も物体側のレンズ面の曲率、および最も像側のレンズ面の曲率を各々Ｒ１ｏｂｊ、Ｒ１ｉｍｇ、広角端および望遠端のバックフォーカスを各々ＢＦｗ、ＢＦｔとしたとき、以下の条件式を満足する。 Specifically, the zoom lens of the present invention includes a first lens group having a positive refractive power and a second lens group having a negative refractive power, which are arranged in order from the object side to the image side. , is a zoom lens in which the distance between adjacent lens groups changes during zooming. The first lens group is composed of one negative lens and one positive lens in order from the object side to the image side. The anomalous dispersion of the negative lens included in the first lens group is Δθgf1n, the Abbe number and partial dispersion ratio of the negative lens are νd1n and θgf1n, respectively, the curvature of the lens surface closest to the object side of the first lens group, and the most image side When the curvature of the lens surface is R1obj and R1img, respectively, and the back focus at the wide-angle end and the telephoto end is BFw and BFt, respectively, the following conditional expression is satisfied.
Δθｇｆ１ｎ＜０ （１）
Δθｇｆ１ｎ＝θｇｆ１ｎ－（－１．６６５Ｅ－７×νｄ１ｎ^３＋５．２１３Ｅ－５×νｄ１ｎ^２－５．６５６Ｅ－３×νｄ１ｎ＋０．７２６８）
－０．９＜（Ｒ１ｏｂｊ＋Ｒ１ｉｍｇ）／（Ｒ１ｏｂｊ－Ｒ１ｉｍｇ）＜０ （２）
２．３＜ＢＦｔ／ＢＦｗ＜４．５ （３）
ここで、Ｅ±ｎは、１０^±ｎを意味する（ｎは自然数）。
Δθgf1n<0 (1)
Δθgf1n=θgf1n-(-1.665E-7×νd1n^3+5.213E-5×νd1n^2-5.656E-3×νd1n+0.7268)
-0.9<(R1obj+R1img)/(R1obj-R1img)<0 (2)
2.3<BFt/BFw<4.5 (3)
Here, E±n means 10^±n (n is a natural number).
前述したように、本発明では第１レンズ群の硝材および形状、最も像側のレンズ群の移動を適切に設定することが重要となる。 As described above, in the present invention, it is important to appropriately set the glass material and shape of the first lens group and the movement of the lens group closest to the image side.
条件式（１）は、第１レンズ群の負レンズの硝材に関する条件式であり、特に望遠端の軸上色収差の補正に関する条件式である。条件式（１）の上限値を上回ると、高屈折率側の硝材となるため望遠側の球面収差を補正する上で有利となるが、異常分散性が大きくなり、特に望遠側の２次の色消しを行う上で不利となる。 Conditional expression (1) is a conditional expression concerning the glass material of the negative lens of the first lens group, and is particularly a conditional expression concerning correction of longitudinal chromatic aberration at the telephoto end. If the upper limit of conditional expression (1) is exceeded, the glass material has a high refractive index, which is advantageous in correcting spherical aberration on the telephoto side, but the anomalous dispersion becomes large, and especially the second order on the telephoto side This is disadvantageous when performing color erasure.
条件式（２）は、第１レンズ群の最も物体側のレンズ面と最も像側のレンズ面の曲率に関する条件式であり、特に望遠端の球面収差、ズーム全域のコマ収差に関する条件式である。条件式（２）の下限値を下回ると、第１レンズ群全体の形状が強いメニスカス形状となるため、ズーム全域で内向性のコマが強まるため好ましくない。また、正レンズの屈折力が弱まるため望遠側の軸上色収差を補正する上で困難となる。一方、条件式（２）の上限値を上回ると、第１レンズ群全体の形状が強い両凸形状となるため、外向性のコマが強まるため好ましくない。また、望遠側の球面収差を補正する上で困難となる。 Conditional expression (2) is a conditional expression regarding the curvature of the lens surface closest to the object side and the lens surface closest to the image side of the first lens group, and is particularly concerned with spherical aberration at the telephoto end and coma aberration throughout the zoom range. . If the lower limit of conditional expression (2) is exceeded, the shape of the first lens group as a whole becomes a strong meniscus shape, which is not preferable because the introverted coma becomes stronger over the entire zoom range. Furthermore, since the refractive power of the positive lens is weakened, it becomes difficult to correct longitudinal chromatic aberration on the telephoto side. On the other hand, if the upper limit of conditional expression (2) is exceeded, the shape of the entire first lens group becomes strongly biconvex, which is not preferable because the extroverted coma becomes stronger. Furthermore, it becomes difficult to correct spherical aberration on the telephoto side.
条件式（３）は、広角端と望遠端のバックフォーカスの比に関する条件式であり、特にズーム全域の倍率色収差に関する条件式である。条件式（３）の下限値を下回ると、広角端と望遠端での最も像側のレンズ群の位置の変化が少なくなるため、変倍時の倍率色収差変動を抑えることが困難となる。一方、条件式（３）の上限値を上回ると、広角端と望遠端での最も像側のレンズ群の位置の変化が大きくなる。このため、変倍時の倍率色収差変動を抑える上で有利となるが、移動量を確保するためにレンズ全長が大型化するため好ましくない。 Conditional expression (3) is a conditional expression regarding the ratio of back focus between the wide-angle end and the telephoto end, and in particular, is a conditional expression regarding lateral chromatic aberration over the entire zoom range. If the lower limit of conditional expression (3) is not reached, there will be little change in the position of the lens group closest to the image between the wide-angle end and the telephoto end, making it difficult to suppress fluctuations in lateral chromatic aberration during zooming. On the other hand, when the upper limit of conditional expression (3) is exceeded, the change in the position of the lens group closest to the image side between the wide-angle end and the telephoto end becomes large. This is advantageous in suppressing variations in chromatic aberration of magnification during zooming, but it is not preferable because the overall length of the lens becomes large in order to ensure the amount of movement.
なお、収差補正上更に好ましくは、条件式（１）～（３）の数値範囲を次の如く設定するのが良い。 Furthermore, from the viewpoint of aberration correction, it is more preferable to set the numerical ranges of conditional expressions (1) to (3) as follows.
－０．０１＜Δθｇｆ１ｎ＜０ （１ａ）
－０．８７＜（Ｒ１ｏｂｊ＋Ｒ１ｉｍｇ）／（Ｒ１ｏｂｊ－Ｒ１ｉｍｇ）＜－０．１ （２ａ）
２．４＜ＢＦｔ／ＢＦｗ＜４．３ （３ａ）
より更に好ましくは、条件式（１）～（３）の数値範囲を次の如く設定するのが良い。
-0.01<Δθgf1n<0 (1a)
-0.87<(R1obj+R1img)/(R1obj-R1img)<-0.1 (2a)
2.4<BFt/BFw<4.3 (3a)
Even more preferably, the numerical ranges of conditional expressions (1) to (3) are set as follows.
－０．００７＜Δθｇｆ１ｎ＜０ （１ｂ）
－０．８５＜（Ｒ１ｏｂｊ＋Ｒ１ｉｍｇ）／（Ｒ１ｏｂｊ－Ｒ１ｉｍｇ）＜－０．２ （２ｂ）
２．５＜ＢＦｔ／ＢＦｗ＜４．０ （３ｂ）
上記条件式で本発明の目的は達成される。ただし、より好ましくは、本発明のズームレンズは、第２レンズ群よりも像側に、最も像側に負の屈折力を有するレンズ群Ｒｎを含む複数のレンズ群から成る後続群を有し、レンズ群Ｒｎの焦点距離をｆＲｎ、第１レンズ群の焦点距離をｆ１としたとき、
－１．２０＜ｆＲｎ／ｆ１＜－０．４５ （４）
なる条件式を満足することである。
-0.007<Δθgf1n<0 (1b)
-0.85<(R1obj+R1img)/(R1obj-R1img)<-0.2 (2b)
2.5<BFt/BFw<4.0 (3b)
The object of the present invention is achieved with the above conditional expression. However, more preferably, the zoom lens of the present invention has a subsequent group composed of a plurality of lens groups including a lens group Rn having a negative refractive power closest to the image side, which is closer to the image side than the second lens group, When the focal length of the lens group Rn is fRn and the focal length of the first lens group is f1,
-1.20<fRn/f1<-0.45 (4)
It is necessary to satisfy the following conditional expression.
条件式（４）は、第２レンズ群より像側に配置された最も像側のレンズ群と第１レンズ群の焦点距離の比に関する条件式であり、特に倍率色収差補正、像面湾曲補正に関する条件式である。条件式（４）の下限値を下回ると、レンズ群Ｒｎの屈折力が弱まり、変倍による倍率色収差の変動を補正する上で困難となる。一方、条件式（４）の上限値を上回ると、レンズ群Ｒｎの屈折力が強まり、像面湾曲を補正する上で困難となる。また、撮像素子への光線入射角が大きくなり、色シェーディング等を起こすため好ましくない。 Conditional expression (4) is a conditional expression regarding the ratio of the focal length of the first lens group and the lens group located closest to the image side than the second lens group, and particularly relates to correction of chromatic aberration of magnification and correction of curvature of field. It is a conditional expression. When the lower limit of conditional expression (4) is exceeded, the refractive power of the lens group Rn weakens, making it difficult to correct variations in lateral chromatic aberration due to zooming. On the other hand, when the upper limit of conditional expression (4) is exceeded, the refractive power of the lens group Rn becomes stronger, making it difficult to correct field curvature. Furthermore, the angle of incidence of the light rays on the image sensor becomes large, causing color shading, etc., which is not preferable.
上記同様に、より好ましくは、レンズ群Ｒｎに含まれる負レンズの硝材の異常分散性をΔθｇｆＲｎとしたとき、
ΔθｇｆＲｎ＞０．０１ （５）
なる条件式を満足することである。
Similarly to the above, more preferably, when the anomalous dispersion of the glass material of the negative lens included in the lens group Rn is ΔθgfRn,
ΔθgfRn>0.01 (5)
It is necessary to satisfy the following conditional expression.
条件式（５）は、後続群に含まれるレンズ群Ｒｎの負レンズの硝材に関する条件式であり、特に変倍時の倍率色収差変動に関する条件式である。条件式（５）の下限値を下回ると、異常分散性が小さくなり、変倍時の倍率色収差変動を抑える上で困難となる。 Conditional expression (5) is a conditional expression regarding the glass material of the negative lens of the lens group Rn included in the subsequent group, and in particular is a conditional expression regarding fluctuations in chromatic aberration of magnification during zooming. When the lower limit of conditional expression (5) is exceeded, the anomalous dispersion becomes small, making it difficult to suppress fluctuations in lateral chromatic aberration during zooming.
上記同様に、より好ましくは、該第ｉレンズ群の焦点距離をｆｉとしたとき、
－４．０＜ｆ１／ｆ２＜－２．０ （６）
なる条件式を満足することである。
Similarly to the above, more preferably, when the focal length of the i-th lens group is fi,
-4.0<f1/f2<-2.0 (6)
It is necessary to satisfy the following conditional expression.
条件式（６）は、第１レンズ群と第２レンズ群の焦点距離の比に関する条件式であり、特に光学全長、変倍時の収差変動に関する条件式である。条件式（６）の下限値を下回ると、第２レンズ群に比べて第１レンズ群の屈折力が弱まる。このため望遠側の軸上色収差を補正する上で困難となる。また、変倍量を大きくするために第１レンズ群の移動量が大きくなるため、レンズ全長が大型化するため好ましくない。一方、条件式（６）の上限値を上回ると、第１レンズ群に比べて第２レンズ群の屈折力が弱まるため、特に広角端の像面湾曲、コマ収差を補正する上で困難となる。 Conditional expression (6) is a conditional expression regarding the ratio of the focal lengths of the first lens group and the second lens group, and is particularly a conditional expression regarding the overall optical length and aberration fluctuations during zooming. When the lower limit of conditional expression (6) is exceeded, the refractive power of the first lens group becomes weaker than that of the second lens group. This makes it difficult to correct longitudinal chromatic aberration on the telephoto side. Furthermore, since the amount of movement of the first lens group increases in order to increase the amount of magnification change, the overall length of the lens increases, which is not preferable. On the other hand, if the upper limit of conditional expression (6) is exceeded, the refractive power of the second lens group becomes weaker than that of the first lens group, making it difficult to correct curvature of field and coma, especially at the wide-angle end. .
上記同様に、より好ましくは、該第１レンズ群の広角端から望遠端までの移動量をＭ１としたとき、
－０．５０＜Ｍ１／ｆ１＜－０．２５ （７）
なる条件式を満足することである。ここで、移動量の符号は像側への移動をプラス、物体側への移動をマイナスとする。
Similarly to the above, more preferably, when the amount of movement of the first lens group from the wide-angle end to the telephoto end is M1,
-0.50<M1/f1<-0.25 (7)
It is necessary to satisfy the following conditional expression. Here, the sign of the movement amount is positive for movement toward the image side and negative for movement toward the object side.
条件式（７）は、第１レンズ群の変倍時の移動量と焦点距離に関する条件式であり、特に光学全長、望遠側の収差補正に関する条件式である。条件式（７）の下限値を下回ると、第１レンズ群の屈折力が強まるため、球面収差補正を行う上で困難となる。また、第１レンズ群の変倍時の移動量が大きくなるため、光学全長が大型化するため好ましくない。一方、条件式（７）の上限値を上回ると、第１レンズ群の屈折力が弱まるため、望遠端の軸上色収差を補正する上で困難となる。 Conditional expression (7) is a conditional expression regarding the amount of movement of the first lens group during zooming and the focal length, and is particularly a conditional expression regarding the optical total length and aberration correction on the telephoto side. If the lower limit of conditional expression (7) is not reached, the refractive power of the first lens group becomes stronger, making it difficult to correct spherical aberration. Furthermore, since the amount of movement of the first lens group during zooming becomes large, the total optical length becomes large, which is not preferable. On the other hand, if the upper limit of conditional expression (7) is exceeded, the refractive power of the first lens group weakens, making it difficult to correct longitudinal chromatic aberration at the telephoto end.
上記同様に、より好ましくは、第１レンズの最も像側のレンズ面の曲率をＲ１ｉｍｇ、第２レンズ群の最も物体側のレンズ面の曲率をＲ２ｏｂｊとしたとき、
１．２＜（Ｒ１ｉｍｇ＋Ｒ２ｏｂｊ）／（Ｒ１ｉｍｇ－Ｒ２ｏｂｊ）＜３．５ （８）
なる条件式を満足することである。
Similarly to the above, more preferably, when the curvature of the lens surface closest to the image side of the first lens is R1img, and the curvature of the lens surface closest to the object side of the second lens group is R2obj,
1.2<(R1img+R2obj)/(R1img-R2obj)<3.5 (8)
It is necessary to satisfy the following conditional expression.
条件式（８）は、第１レンズ群と第２レンズ群の間の空気レンズに関する条件式であり、特に防振時の光学性能に関する条件式である。条件式（８）の下限値を下回ると、空気レンズの形状が平凸形状に近づき、防振時の像面湾曲変動が大きくなるため好ましくない。一方、条件式（８）の上限値を上回ると、空気レンズの形状が像側に凸の強いメニスカス形状となる。このため、防振時のコマ収差変動、像面湾曲変動に対しては有利だが、通常時の球面収差補正、外向性のコマを補正する上で困難となる。 Conditional expression (8) is a conditional expression regarding the air lens between the first lens group and the second lens group, and is particularly a conditional expression regarding optical performance during image stabilization. If the lower limit of conditional expression (8) is not reached, the shape of the air lens approaches a plano-convex shape, which is not preferable because the fluctuation of the curvature of field during image stabilization increases. On the other hand, when the upper limit of conditional expression (8) is exceeded, the shape of the air lens becomes a meniscus shape with a strong convexity toward the image side. For this reason, although this is advantageous against fluctuations in comatic aberration and fluctuations in curvature of field during image stabilization, it is difficult to correct spherical aberration during normal use and to correct extroverted coma.
なお、収差補正上更に好ましくは、条件式（４）～（８）の数値範囲を次の如く設定するのが良い。 In addition, from the viewpoint of aberration correction, it is more preferable to set the numerical ranges of conditional expressions (4) to (8) as follows.
－１．１０＜ｆＲｎ／ｆ１＜－０．４６ （４ａ）
０．０３＞ΔθｇｆＲｎ＞０．０１ （５ａ）
－３．８＜ｆ１／ｆ２＜－２．２ （６ａ）
－０．４８＜Ｍ１／ｆ１＜０．２７ （７ａ）
１．３＜（Ｒ１ｉｍｇ＋Ｒ２ｏｂｊ）／（Ｒ１ｉｍｇ－Ｒ２ｏｂｊ）＜３．３ （８ａ）
より更に好ましくは、条件式（４）～（８）の数値範囲を次の如く設定するのが良い。
-1.10<fRn/f1<-0.46 (4a)
0.03>ΔθgfRn>0.01 (5a)
-3.8<f1/f2<-2.2 (6a)
-0.48<M1/f1<0.27 (7a)
1.3<(R1img+R2obj)/(R1img-R2obj)<3.3 (8a)
Even more preferably, the numerical ranges of conditional expressions (4) to (8) are set as follows.
－１．００＜ｆＲｎ／ｆ１＜－０．４７ （４ｂ）
０．０２５＞ΔθｇｆＲｎ＞０．０１ （５ｂ）
－３．５＜ｆ１／ｆ２＜－２．５ （６ｂ）
－０．４５＜Ｍ１／ｆ１＜－０．３ （７ｂ）
１．４＜（Ｒ１ｉｍｇ＋Ｒ２ｏｂｊ）／（Ｒ１ｉｍｇ－Ｒ２ｏｂｊ）＜３．０ （８ｂ）
更に撮影時には、第２レンズ群を光軸に対して垂直方向に移動させることによって光軸に対して垂直な成分を含む方向に被写体像を変移させている。これにより、被写体像の像面移動を補正し、光学系全体が振動した際の撮影画像のブレを補正している。ここでいう垂直とは、厳密な意味での垂直だけでなく、垂直方向からわずかにずれた方向も含む意である。
-1.00<fRn/f1<-0.47 (4b)
0.025>ΔθgfRn>0.01 (5b)
-3.5<f1/f2<-2.5 (6b)
-0.45<M1/f1<-0.3 (7b)
1.4<(R1img+R2obj)/(R1img-R2obj)<3.0 (8b)
Furthermore, during photographing, the second lens group is moved in a direction perpendicular to the optical axis, thereby shifting the subject image in a direction that includes a component perpendicular to the optical axis. This corrects the movement of the image plane of the subject image and corrects blurring of the captured image when the entire optical system vibrates. Vertical here includes not only vertical in the strict sense but also directions slightly deviated from the vertical direction.
なお、本発明のズームレンズにおいて、諸収差のうち歪曲収差の補正は、電気的な画像処理によって行われても良い。特に、広角側での撮像素子の有効撮像範囲（有効像円径）を望遠端での有効撮像範囲（有効像円径）より小さくし、上記歪曲収差の補正を行うことによって、前玉径の小型化に寄与する。 Note that in the zoom lens of the present invention, correction of distortion among various aberrations may be performed by electrical image processing. In particular, by making the effective imaging range (effective image circle diameter) of the image sensor at the wide-angle end smaller than the effective imaging range (effective image circle diameter) at the telephoto end and correcting the above-mentioned distortion, the diameter of the front lens can be reduced. Contributes to miniaturization.
本発明では、以上のように各レンズ群を構成することによって、ショートバックに対応し、安価でズーム全域で光学性能が良好なズームレンズ及びそれを有する光学機器を得ている。 In the present invention, by configuring each lens group as described above, it is possible to obtain a zoom lens that is compatible with short backs, is inexpensive, and has good optical performance over the entire zoom range, and an optical device having the same.
以下に、本発明のズームレンズの各実施例について図面を参照して説明する。まず、各レンズ群のレンズ構成について説明する。以下の各レンズ群の説明は、実施例１～４に主に当てはまる。 Embodiments of the zoom lens of the present invention will be described below with reference to the drawings. First, the lens configuration of each lens group will be explained. The following description of each lens group mainly applies to Examples 1 to 4.
第１レンズ群Ｌ１は、物体側のレンズ面が凸形状の負メニスカスレンズと像側のレンズ面が弱い凸形状の正レンズとを接合した接合レンズであり、最小枚数で構成された接合レンズである。各実施例のズームレンズでは小型にするために第１レンズ群Ｌ１の屈折力を適切な範囲で強めている。屈折力を強めた際、第１レンズ群Ｌ１内で発生する諸収差、特に望遠側において球面収差が多く発生してくる。そこで、第１レンズ群Ｌ１の像側面を弱い凸とした適切な形状とすることで諸収差の発生を低減している。また、負レンズに部分分散比の小さい低分散の硝材、正レンズに部分分散比の大きい高分散の硝材を使用することで特に望遠側での軸上色収差を良好に補正する様にしている。 The first lens group L1 is a cemented lens made by cementing a negative meniscus lens with a convex lens surface on the object side and a positive lens with a weakly convex lens surface on the image side, and is a cemented lens composed of the minimum number of lenses. be. In the zoom lens of each embodiment, the refractive power of the first lens group L1 is strengthened within an appropriate range in order to make the zoom lens compact. When the refractive power is strengthened, various aberrations occur within the first lens group L1, especially spherical aberration on the telephoto side. Therefore, the occurrence of various aberrations is reduced by giving the image side surface of the first lens group L1 an appropriate shape with a weak convexity. In addition, by using a low-dispersion glass material with a small partial dispersion ratio for the negative lens and a high-dispersion glass material with a large partial dispersion ratio for the positive lens, longitudinal chromatic aberration, especially on the telephoto side, is effectively corrected.
第２レンズ群Ｌ２は、屈折力の絶対値が物体側に比べて像側に強く、像側のレンズ面が凹形状の負レンズ、両側のレンズ面が凹形状の負レンズ、および物体側のレンズ面が凸形状の正レンズと、を接合した接合レンズで構成している。各実施例のズームレンズでは、高変倍比の達成と光学全長の短縮を行うために第２レンズ群Ｌ２の屈折力を適切な範囲で強めている。屈折力を強めた際、第２レンズ群Ｌ２で発生する諸収差、特に広角側において像面湾曲、倍率色収差が多く発生してくる。各実施例では、第２レンズ群Ｌ２の負の屈折力を２枚の負レンズで分担することで、像面湾曲の発生を低減している。また、正レンズに高分散のガラスを使用することによって倍率色収差を抑制している。 The second lens group L2 has a negative lens whose absolute value of refractive power is stronger on the image side than on the object side, a negative lens with a concave lens surface on the image side, a negative lens with concave lens surfaces on both sides, and a negative lens with a concave lens surface on both sides. It consists of a positive lens with a convex lens surface and a cemented lens. In the zoom lens of each embodiment, the refractive power of the second lens group L2 is strengthened within an appropriate range in order to achieve a high zoom ratio and shorten the overall optical length. When the refractive power is strengthened, various aberrations occur in the second lens group L2, particularly curvature of field and lateral chromatic aberration on the wide-angle side. In each embodiment, the negative refractive power of the second lens group L2 is shared by two negative lenses, thereby reducing the occurrence of field curvature. Also, by using high-dispersion glass for the positive lens, chromatic aberration of magnification is suppressed.
第３レンズ群Ｌ３は、物体側のレンズ面が凸形状の正レンズ、物体側のレンズ面が凸形状の正レンズ、および物体側のレンズ面が凹形状の負レンズと、を接合した接合レンズで構成している。各実施例のズームレンズでは、小型化のために第３レンズ群Ｌ３の屈折力を適切な範囲で強めている。屈折力を強めた際、第３レンズ群Ｌ３で発生する諸収差、特に広角端の球面収差、コマ収差、軸上色収差が多く発生してくる。そこで、第３レンズ群Ｌ３の正の屈折力を複数の正レンズで分担することで、球面収差、コマ収差の発生を低減している。また、接合レンズを配置し、正レンズに異常分散性の大きい硝材を使用することで、軸上色収差の発生を低減している。 The third lens group L3 is a cemented lens consisting of a positive lens with a convex lens surface on the object side, a positive lens with a convex lens surface on the object side, and a negative lens with a concave lens surface on the object side. It consists of In the zoom lens of each example, the refractive power of the third lens group L3 is strengthened within an appropriate range for miniaturization. When the refractive power is increased, various aberrations occur in the third lens group L3, especially spherical aberration, coma aberration, and longitudinal chromatic aberration at the wide-angle end. Therefore, by sharing the positive refractive power of the third lens group L3 with a plurality of positive lenses, the occurrence of spherical aberration and coma aberration is reduced. Additionally, by arranging a cemented lens and using a glass material with high anomalous dispersion for the positive lens, the occurrence of axial chromatic aberration is reduced.
第４レンズ群Ｌ４は、物体側のレンズ面が凹形状の負メニスカスレンズ１枚で構成している。各実施例のズームレンズでは、少ないレンズ枚数で第４レンズ群Ｌ４を構成することで、光学全長の短縮を図っている。特に物体側を凹形状のメニスカス形状とすることで、第３レンズ群Ｌ３で発生した球面収差の補正を行っている。 The fourth lens group L4 includes one negative meniscus lens whose object-side lens surface is concave. In the zoom lens of each embodiment, the fourth lens group L4 is configured with a small number of lenses, thereby reducing the total optical length. In particular, by forming the object side into a concave meniscus shape, the spherical aberration generated in the third lens group L3 is corrected.
第５レンズ群Ｌ５は、物体側のレンズ面が凸形状の正レンズ、物体側のレンズ面が凸形状の正レンズ、および物体側面が凹形状の負レンズと、を接合した接合レンズで構成している。各実施例のズームレンズでは、小型化のために第５レンズ群Ｌ５の屈折力を適切な範囲で強めている。屈折力を強めた際、第５レンズ群Ｌ５で発生する諸収差、特に広角端の球面収差、コマ収差が多く発生してくる。そこで、第５レンズ群Ｌ５の正の屈折力を複数の正レンズで分担することで球面収差、コマ収差の発生を低減している。また、接合レンズを配置し、正レンズに異常分散性の大きい硝材を使用することでズーム全域の軸上色収差の発生を低減している。 The fifth lens group L5 is composed of a cemented lens that includes a positive lens with a convex object-side lens surface, a positive lens with a convex object-side lens surface, and a negative lens with a concave object-side lens surface. ing. In the zoom lens of each example, the refractive power of the fifth lens group L5 is strengthened within an appropriate range for miniaturization. When the refractive power is strengthened, various aberrations occur in the fifth lens group L5, especially spherical aberration and coma aberration at the wide-angle end. Therefore, by sharing the positive refractive power of the fifth lens group L5 with a plurality of positive lenses, the occurrence of spherical aberration and coma aberration is reduced. Furthermore, by arranging a cemented lens and using a glass material with high anomalous dispersion for the positive lens, the occurrence of axial chromatic aberration over the entire zoom range is reduced.
第６レンズ群Ｌ６は、両側のレンズ面が凸形状の正レンズと両側のレンズ面が凹形状の負レンズとを接合した接合レンズで構成している。各実施例のズームレンズでは、変倍比を稼ぐために第６レンズ群Ｌ６の屈折力を適切な範囲で強めている。屈折力を強めた際、第６レンズ群Ｌ６で発生する諸収差、特にコマ収差、倍率色収差が多く発生してくる。各実施例では、接合レンズを像側凹のメニスカス形状とすることでコマ収差の発生を低減している。また、正レンズに部分分散比の小さい低分散材料を使用し、接合レンズとすることで倍率色収差を抑制している。 The sixth lens group L6 is composed of a cemented lens in which a positive lens with convex lens surfaces on both sides and a negative lens with concave lens surfaces on both sides are cemented together. In the zoom lens of each example, the refractive power of the sixth lens group L6 is strengthened within an appropriate range in order to increase the zoom ratio. When the refractive power is strengthened, various aberrations occur in the sixth lens group L6, particularly coma aberration and lateral chromatic aberration. In each embodiment, the occurrence of comatic aberration is reduced by forming the cemented lens into a meniscus shape concave on the image side. Furthermore, by using a low dispersion material with a small partial dispersion ratio for the positive lens and forming a cemented lens, chromatic aberration of magnification is suppressed.
第７レンズ群Ｌ７は、物体側凹形状の負メニスカスレンズ１枚で構成している。各実施例のズームレンズでは、少ないレンズ枚数で第７レンズ群Ｌ７を構成することで光学全長の短縮を図っている。特に物体側を凹形状のメニスカス形状とすることで撮像素子への斜入射を抑制している。また、負レンズに部分分散の大きい高分散の硝材を使用し、変倍時の移動量を大きくすることで変倍時の倍率色収差変動を抑制している。
（実施例１乃至４）
図１、５、９、１３は、それぞれ実施例１乃至４のズームレンズの広角端におけるレンズ断面図であり、各図において、左方が被写体側で、右方が像側である。レンズ断面図において、Ｌ１は正の屈折力を有する第１レンズ群、Ｌ２は負の屈折力を有する第２レンズ群、Ｌ３は正の屈折力を有する第３レンズ群である。Ｌ４は負の屈折力を有する第４レンズ群、Ｌ５は正の屈折力を有する第５レンズ群、Ｌ６は負の屈折力を有する第６レンズ群、Ｌ７は負の屈折力を有する第７レンズ群である。ＳＰは開口絞りであり、第３レンズ群Ｌ３の像側に位置しており、ズーミングに際して第３レンズ群Ｌ３と一体に移動する。
The seventh lens group L7 is composed of one negative meniscus lens having a concave shape on the object side. In the zoom lens of each example, the total optical length is shortened by configuring the seventh lens group L7 with a small number of lenses. In particular, by forming the object side into a concave meniscus shape, oblique incidence on the image sensor is suppressed. In addition, by using a high-dispersion glass material with large partial dispersion for the negative lens and increasing the amount of movement during zooming, fluctuations in chromatic aberration of magnification are suppressed during zooming.
(Examples 1 to 4)
1, 5, 9, and 13 are lens sectional views at the wide-angle end of the zoom lenses of Examples 1 to 4, respectively, and in each figure, the left side is the object side and the right side is the image side. In the lens cross-sectional view, L1 is a first lens group with positive refractive power, L2 is a second lens group with negative refractive power, and L3 is a third lens group with positive refractive power. L4 is the fourth lens group with negative refractive power, L5 is the fifth lens group with positive refractive power, L6 is the sixth lens group with negative refractive power, and L7 is the seventh lens group with negative refractive power. It is a group. SP is an aperture stop located on the image side of the third lens group L3, and moves together with the third lens group L3 during zooming.
ＩＰは像面であり、デジタルスチルカメラやビデオカメラの撮影光学系として使用する際にはＣＣＤセンサやＣＭＯＳセンサ等の固体撮像素子の撮像面が、銀塩フィルム用カメラのときはフィルム面に相当する。 IP is the image plane, and when used as the photographing optical system of a digital still camera or video camera, the imaging plane of a solid-state image sensor such as a CCD sensor or CMOS sensor corresponds to the film plane when using a silver halide film camera. do.
ここで、各実施例の収差図において、ｄ，ｇは各々ｄ線及びｇ線、ΔＭ，ΔＳはメリジオナル像面、サジタル像面、倍率色収差はｇ線によって表している。また、ＦｎｏはＦナンバー、ωは半画角（°）である。 Here, in the aberration diagrams of each example, d and g are the d-line and g-line, respectively, ΔM and ΔS are the meridional image plane and sagittal image plane, and chromatic aberration of magnification is expressed by the g-line. Further, Fno is the F number, and ω is the half angle of view (°).
なお、各実施例において広角端と望遠端は変倍レンズ群が機構上光軸上移動可能な範囲の両端に位置したときのズーム位置をいう。 Note that in each embodiment, the wide-angle end and the telephoto end refer to zoom positions when the variable power lens group is located at both ends of a range in which it is mechanically movable on the optical axis.
実施例１乃至４では、広角端から望遠端へのズーミングに際して矢印のように、第１レンズ群Ｌ1を物体側へ、第３レンズ群Ｌ３と第５レンズ群Ｌ５を一体で物体側へ、第４レンズ群Ｌ４を物体側へ、第７レンズ群Ｌ７を物体側へ移動することによって変倍を行う。また、第６レンズ群Ｌ６を物体側に移動させることで変倍に伴う像面変動を補正している。第２レンズ群は変倍時像面に対して固定である。 In Examples 1 to 4, when zooming from the wide-angle end to the telephoto end, the first lens group L1 is moved toward the object side, the third lens group L3 and the fifth lens group L5 are integrally moved toward the object side, and the third lens group The magnification is changed by moving the fourth lens group L4 toward the object side and the seventh lens group L7 toward the object side. Further, by moving the sixth lens group L6 toward the object side, image plane fluctuations caused by zooming are corrected. The second lens group is fixed with respect to the image plane during zooming.
また、第４レンズ群Ｌ４と第６レンズ群Ｌ６を光軸上に移動させてフォーカシングを行うフローティングフォーカス方式を採用している。第４レンズ群Ｌ４に関する実線の曲線４ａと点線の曲線４ｂは、各々無限遠物体と近距離物体にフォーカスしているときの変倍に伴う像面変動を補正するための移動軌跡である。第４レンズ群Ｌ４を物体側へ移動させることで、第３レンズ群Ｌ３と第５レンズ群Ｌ５との間の空間の有効利用を図り、光学全長の短縮化を効果的に達成している。一方、第６レンズ群Ｌ６に関する実線の曲線6ａと点線の曲線6ｂは、各々無限遠物体と近距離物体にフォーカスしているときの変倍に伴う像面変動を補正するための移動軌跡である。このように第6レンズ群Ｌ6を像側へ移動させることで第５レンズ群Ｌ５と第７レンズ群Ｌ７との間の空間の有効利用を図り、光学全長の短縮化を効果的に達成している。 Further, a floating focus method is adopted in which focusing is performed by moving the fourth lens group L4 and the sixth lens group L6 on the optical axis. A solid curve 4a and a dotted curve 4b regarding the fourth lens group L4 are movement trajectories for correcting image plane fluctuations associated with zooming when focusing on an object at infinity and a close object, respectively. By moving the fourth lens group L4 toward the object side, the space between the third lens group L3 and the fifth lens group L5 is effectively utilized, and the overall optical length is effectively shortened. On the other hand, a solid curve 6a and a dotted curve 6b regarding the sixth lens group L6 are movement trajectories for correcting image plane fluctuations associated with zooming when focusing on an object at infinity and a close object, respectively. . By moving the sixth lens group L6 toward the image side in this way, the space between the fifth lens group L5 and the seventh lens group L7 can be used effectively, and the overall optical length can be effectively shortened. There is.
また、望遠端において無限遠物体から近距離物体へフォーカスを行う場合には、矢印４ｃ、６ｃに示すように第４レンズ群Ｌ４を前方に繰り出し、第６レンズ群Ｌ６を後方に繰り込むことで行っている。尚、第１レンズ群Ｌ１はフォーカスの為には光軸方向に固定であるが、収差補正上必要に応じて移動させてもよい。 In addition, when focusing from an object at infinity to a close object at the telephoto end, the fourth lens group L4 is extended forward and the sixth lens group L6 is retracted backward, as shown by arrows 4c and 6c. Is going. Note that the first lens group L1 is fixed in the optical axis direction for focusing, but may be moved as necessary for aberration correction.
（実施例５）
図１７は、実施例５のズームレンズの広角端におけるレンズ断面図であり、図において、左方が被写体側で、右方が像側である。レンズ断面図において、Ｌ１は正の屈折力を有する第１レンズ群、Ｌ２は負の屈折力を有する第２レンズ群である。また、Ｌ３は正の屈折力を有する第３レンズ群、Ｌ４は正の屈折力を有する第４レンズ群、Ｌ５は負の屈折力を有する第５レンズ群、Ｌ６は負の屈折力を有する第６レンズ群である。ＳＰは開口絞りであり、第３レンズ群Ｌ３の物体側に位置しており、ズーミングに際して第３レンズ群Ｌ３と一体移動である。ＩＰは像面である。
(Example 5)
FIG. 17 is a cross-sectional view of the zoom lens of Example 5 at the wide-angle end. In the figure, the left side is the subject side and the right side is the image side. In the lens cross-sectional view, L1 is a first lens group having positive refractive power, and L2 is a second lens group having negative refractive power. Further, L3 is a third lens group having a positive refractive power, L4 is a fourth lens group having a positive refractive power, L5 is a fifth lens group having a negative refractive power, and L6 is a third lens group having a negative refractive power. There are 6 lens groups. SP is an aperture stop, located on the object side of the third lens group L3, and moves integrally with the third lens group L3 during zooming. IP is the image plane.
実施例５では、広角端から望遠端へのズーミングに際して矢印のように、第１レンズ群Ｌ1を物体側に移動、第３レンズ群Ｌ３を物体側に移動、第４レンズ群Ｌ４を物体側へ移動、第６レンズ群Ｌ６を物体側へ移動することによって変倍を行う。また、第５レンズ群L５を物体側に移動させることで変倍に伴う像面変動を補正している。第２レンズ群は変倍時像面に対して固定である。 In Example 5, when zooming from the wide-angle end to the telephoto end, the first lens group L1 is moved toward the object side, the third lens group L3 is moved toward the object side, and the fourth lens group L4 is moved toward the object side, as shown by the arrows. The magnification is changed by moving the sixth lens group L6 toward the object side. Furthermore, by moving the fifth lens group L5 toward the object side, image plane fluctuations caused by zooming are corrected. The second lens group is fixed with respect to the image plane during zooming.
また、第５レンズ群Ｌ５を光軸上移動させてフォーカシングを行うインナーフォーカス方式を採用している。第５レンズ群Ｌ５に関する実線の曲線５ａと点線の曲線５ｂは、各々無限遠物体と近距離物体にフォーカスしているときの変倍に伴う像面変動を補正するための移動軌跡である。このように第５レンズ群Ｌ５を像側へ移動させることで第４レンズ群Ｌ４と第６レンズ群Ｌ６との間の空間の有効利用を図り、光学全長の短縮化を効果的に達成している。 Further, an inner focus method is adopted in which focusing is performed by moving the fifth lens group L5 on the optical axis. A solid curve 5a and a dotted curve 5b regarding the fifth lens group L5 are movement trajectories for correcting image plane fluctuations associated with zooming when focusing on an object at infinity and an object at a short distance, respectively. By moving the fifth lens group L5 toward the image side in this way, the space between the fourth lens group L4 and the sixth lens group L6 can be used effectively, and the total optical length can be effectively shortened. There is.
また、望遠端において無限遠物体から近距離物体へフォーカスを行う場合には、矢印５ｃに示すように第５レンズ群Ｌ５を後方に繰り込むことで行っている。尚、第１レンズ群Ｌ１はフォーカスの為には光軸方向に固定であるが、収差補正上必要に応じて移動させてもよい。
（実施例６）
図２１は、実施例６のズームレンズの広角端におけるレンズ断面図であり、各図において、左方が被写体側で、右方が像側である。レンズ断面図において、Ｌ１は正の屈折力を有する第１レンズ群、Ｌ２は負の屈折力を有する第２レンズ群である。Ｌ３は正の屈折力を有する第３レンズ群、Ｌ４は負の屈折力を有する第４レンズ群、Ｌ５は正の屈折力を有する第５レンズ群、Ｌ６は負の屈折力を有する第６レンズ群、Ｌ７は正の屈折力を有する第７レンズ群、Ｌ８は負の屈折力を有する第８レンズ群である。ＳＰは開口絞りであり、第３レンズ群Ｌ３の像側に位置しており、ズーミングに際して第３レンズ群Ｌ３と一体移動である。ＩＰは像面である。
Furthermore, when focusing from an object at infinity to an object at a short distance at the telephoto end, the fifth lens group L5 is moved rearward as shown by an arrow 5c. Note that the first lens group L1 is fixed in the optical axis direction for focusing, but may be moved as necessary for aberration correction.
(Example 6)
FIG. 21 is a lens sectional view at the wide-angle end of the zoom lens of Example 6, and in each figure, the left side is the subject side and the right side is the image side. In the lens cross-sectional view, L1 is a first lens group having positive refractive power, and L2 is a second lens group having negative refractive power. L3 is the third lens group with positive refractive power, L4 is the fourth lens group with negative refractive power, L5 is the fifth lens group with positive refractive power, and L6 is the sixth lens group with negative refractive power. The group L7 is a seventh lens group having a positive refractive power, and L8 is an eighth lens group having a negative refractive power. SP is an aperture stop, located on the image side of the third lens group L3, and moves integrally with the third lens group L3 during zooming. IP is the image plane.
実施例６では、広角端から望遠端へのズーミングに際して、第１レンズ群Ｌ1を物体側へ、第３レンズ群Ｌ３と第５レンズ群Ｌ５を一体で物体側へ、第４レンズ群Ｌ４、第７レンズ群Ｌ７、第８レンズ群Ｌ８を物体側へ移動することによって変倍を行う。また、第６レンズ群Ｌ６を物体側に移動させることで変倍に伴う像面変動を補正している。第２レンズ群は変倍時像面に対して固定である。 In the sixth embodiment, when zooming from the wide-angle end to the telephoto end, the first lens group L1 is moved toward the object side, the third lens group L3 and the fifth lens group L5 are moved together toward the object side, and the fourth lens group L4 and the third lens group L5 are moved toward the object side. The magnification is changed by moving the seventh lens group L7 and the eighth lens group L8 toward the object side. Further, by moving the sixth lens group L6 toward the object side, image plane fluctuations caused by zooming are corrected. The second lens group is fixed with respect to the image plane during zooming.
また、第４レンズ群Ｌ４と第６レンズ群Ｌ６を光軸上に移動させてフォーカシングを行うフローティングフォーカス方式を採用している。第４レンズ群Ｌ４に関する実線の曲線４ａと点線の曲線４ｂは、各々無限遠物体と近距離物体にフォーカスしているときの変倍に伴う像面変動を補正するための移動軌跡である。第４レンズ群Ｌ４を物体側へ移動させることで、第３レンズ群Ｌ３と第５レンズ群Ｌ５との間の空間の有効利用を図り、光学全長の短縮化を効果的に達成している。一方、第６レンズ群Ｌ６に関する実線の曲線６ａと点線の曲線６ｂは、各々無限遠物体と近距離物体にフォーカスしているときの変倍に伴う像面変動を補正するための移動軌跡である。このように第６レンズ群Ｌ６を像側へ移動させることで、第５レンズ群Ｌ５と第７レンズ群Ｌ７との間の空間の有効利用を図り、光学全長の短縮化を効果的に達成している。 Further, a floating focus method is adopted in which focusing is performed by moving the fourth lens group L4 and the sixth lens group L6 on the optical axis. A solid curve 4a and a dotted curve 4b regarding the fourth lens group L4 are movement trajectories for correcting image plane fluctuations associated with zooming when focusing on an object at infinity and a close object, respectively. By moving the fourth lens group L4 toward the object side, the space between the third lens group L3 and the fifth lens group L5 is effectively utilized, and the overall optical length is effectively shortened. On the other hand, a solid curve 6a and a dotted curve 6b regarding the sixth lens group L6 are movement trajectories for correcting image plane fluctuations associated with zooming when focusing on an object at infinity and a close object, respectively. . By moving the sixth lens group L6 toward the image side in this way, the space between the fifth lens group L5 and the seventh lens group L7 can be used effectively, and the total optical length can be effectively shortened. ing.
また、望遠端において無限遠物体から近距離物体へフォーカスを行う場合には、矢印４ｃ、６ｃに示すように第４レンズ群Ｌ４を前方に繰り出し、第６レンズ群Ｌ６を後方に繰り込むことで行っている。尚、第１レンズ群Ｌ１はフォーカスの為には光軸方向に固定であるが、収差補正上必要に応じて移動させてもよい。 In addition, when focusing from an object at infinity to a close object at the telephoto end, the fourth lens group L4 is extended forward and the sixth lens group L6 is retracted backward, as shown by arrows 4c and 6c. Is going. Note that the first lens group L1 is fixed in the optical axis direction for focusing, but may be moved as necessary for aberration correction.
実施例１乃至４及び実施例６において、フローティングフォーカスは収差補正上有利となる様に第４レンズ群Ｌ４を物体側、第6レンズ群Ｌ６を像側へ移動させている。しかしながら、フォーカス時の各レンズ群の移動量を減らすために第４レンズ群Ｌ４は像側に移動させても良い。 In Examples 1 to 4 and Example 6, the floating focus moves the fourth lens group L4 toward the object side and the sixth lens group L6 toward the image side so as to be advantageous in correcting aberrations. However, in order to reduce the amount of movement of each lens group during focusing, the fourth lens group L4 may be moved toward the image side.
以下に、実施例１～６にそれぞれ対応する数値実施例１～６を示す。 Numerical Examples 1 to 6 corresponding to Examples 1 to 6, respectively, are shown below.
各数値実施例の面データにおいて、ｒは各光学面の曲率半径、ｄ（ｍｍ）は第ｍ面と第（ｍ＋１）面との間の軸上間隔（光軸上の距離）を表わしている。ただし、ｍは光入射側から数えた面の番号である。また、ｎｄは各光学部材のｄ線に対する屈折率、νｄは光学部材のアッベ数を表わしている。なお、ある材料のアッベ数νｄは、フラウンホーファ線のｄ線（５８７．６ｎｍ）、Ｆ線（４８６．１ｎｍ）、Ｃ線（６５６．３ｎｍ）における屈折率をＮｄ、ＮＦ、ＮＣとするとき、
νｄ＝（Ｎｄ－１）／（ＮＦ－ＮＣ）
で表される。
In the surface data of each numerical example, r represents the radius of curvature of each optical surface, and d (mm) represents the axial distance (distance on the optical axis) between the m-th surface and the (m+1)-th surface. . However, m is the number of the surface counted from the light incident side. Further, nd represents the refractive index of each optical member with respect to the d-line, and νd represents the Abbe number of the optical member. In addition, the Abbe number νd of a certain material is given by the refractive index at the Fraunhofer line d line (587.6 nm), F line (486.1 nm), and C line (656.3 nm) as Nd, NF, and NC.
νd=(Nd-1)/(NF-NC)
It is expressed as
なお、各数値実施例において、ｄ、焦点距離（ｍｍ）、Ｆナンバー、半画角（°）は全て各実施例の光学系が無限遠物体に焦点を合わせた時の値である。「バックフォーカス」は、レンズ最終面（最も像側のレンズ面）から近軸像面までの光軸上の距離を空気換算長により表記したものである。「レンズ全長」は、ズームレンズの最前面（最も物体側のレンズ面）から最終面までの光軸上の距離にバックフォーカスを加えた長さである。「レンズ群」は、複数のレンズから構成される場合に限らず、１枚のレンズから構成される場合も含むものとする。 In each numerical example, d, focal length (mm), F number, and half angle of view (°) are all values when the optical system of each example focuses on an object at infinity. "Back focus" is the distance on the optical axis from the final lens surface (the lens surface closest to the image side) to the paraxial image surface expressed in air equivalent length. The "total lens length" is the distance on the optical axis from the frontmost surface (lens surface closest to the object side) to the final surface of the zoom lens plus the back focus. A "lens group" is not limited to a case where it is composed of a plurality of lenses, but also includes a case where it is composed of a single lens.
また、ｋを円錐定数、Ａ４，Ａ６，Ａ８，Ａ１０，Ａ１２を４次、６次、８次、１０次、１２次の非球面係数とし、光軸からの高さｈの位置での光軸方向の変位を面頂点を基準にしてｘとするとき、非球面形状は、
ｘ＝(ｈ２／Ｒ)／[１＋[１－(１＋Ｋ)(ｈ／Ｒ)２]１/２]＋Ａ４ｈ４＋Ａ６ｈ６＋Ａ８ｈ８＋Ａ１０ｈ１０＋Ａ１２ｈ１２
で表示される。但し、Ｒは曲率半径であり、「ｅ－Ｘ」は「×１０-X」を意味している。尚、非球面は各表中の面番号の右側に*印を付している。
In addition, k is a conic constant, A4, A6, A8, A10, and A12 are 4th, 6th, 8th, 10th, and 12th aspherical coefficients, and the optical axis at a height h from the optical axis. When the displacement in the direction is x with respect to the surface vertex, the aspherical shape is
x=(h 2 /R)/[1+[1-(1+K)(h/R) 2 ] 1/2 ]+A4h 4 +A6h 6 +A8h 8 +A10h 10 +A12h 12
is displayed. However, R is the radius of curvature, and "eX" means "×10 -X ". Note that aspherical surfaces are marked with * to the right of the surface number in each table.
また、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。 Further, Table 1 shows the relationship between each of the above-mentioned conditional expressions and various numerical values in the numerical examples.
（数値実施例１）
単位mm
面データ
面番号 r d nd νd
1 112.394 2.75 1.65412 39.7
2 65.388 9.90 1.49700 81.5
3 -402.882 1.50
4 ∞ (可変)
5 -125.993 1.50 1.90043 37.4
6 110.631 2.94
7 -75.566 1.50 1.49700 81.5
8 88.292 3.29 1.80810 22.8
9 -334.236 (可変)
10 49.769 7.30 1.49700 81.5
11 -70.132 0.20
12 60.333 6.39 1.54814 45.8
13 -64.799 1.80 1.95375 32.3
14 146.189 5.00
15(絞り) ∞ (可変)
16 -32.071 1.10 1.49700 81.5
17 -589.673 (可変)
18 148.720 4.03 1.64769 33.8
19 -42.153 0.20
20 58.751 6.45 1.49700 81.5
21 -37.587 1.30 2.00069 25.5
22 -149.927 (可変)
23 171.353 4.56 1.80000 29.8
24 -34.552 1.20 1.78590 44.2
25 43.333 (可変)
26 -35.871 1.40 1.49700 81.5
27 -73.198 (可変)
28 ∞ 1.34 1.51633 64.1
29 ∞ 1.56
像面 ∞
各種データ
ズーム比 3.85
広角 中間 望遠
焦点距離 101.32 119.51 390.00
Ｆナンバー 4.60 4.62 8.20
半画角（°） 12.05 10.26 3.18
像高 21.64 21.64 21.64
レンズ全長 206.13 233.59 294.63
BF 21.63 22.83 66.45
d 4 6.20 33.65 94.70
d 9 36.10 37.54 1.29
d15 14.92 15.08 16.52
d17 13.14 12.98 11.55
d22 16.86 14.24 3.36
d25 32.97 32.95 36.46
d27 19.19 20.40 64.01
ズームレンズ群データ
群 始面 焦点距離 レンズ構成長
1 1 215.80 14.15
2 5 -63.35 9.23
3 10 68.12 20.70
4 16 -68.29 1.10
5 18 45.45 11.98
6 23 -78.20 5.76
7 26 -143.32 1.40
（数値実施例２）
単位 mm
面データ
面番号 r d nd νd
1 104.135 2.75 1.67300 38.3
2 63.657 9.02 1.49700 81.5
3 -467.470 1.50
4 ∞ (可変)
5 -179.352 1.50 1.88100 40.1
6 101.553 3.41
7 -56.081 1.50 1.49700 81.5
8 137.281 3.00 1.80810 22.8
9 -187.787 (可変)
10 44.201 7.53 1.49700 81.5
11 -77.974 0.20
12 56.689 6.63 1.54814 45.8
13 -63.549 1.80 1.95375 32.3
14 116.096 5.00
15(絞り) ∞ (可変)
16 -29.839 1.10 1.49700 81.5
17 -103.584 (可変)
18 110.253 4.03 1.67270 32.1
19 -41.917 0.20
20 61.667 6.64 1.49700 81.5
21 -33.033 1.30 2.00069 25.5
22 -160.251 (可変)
23 -1471.792 4.05 1.71736 29.5
24 -33.018 1.20 1.69680 55.5
25 40.625 (可変)
26 -31.668 1.40 1.49700 81.5
27 -51.022 (可変)
28 ∞ 1.34 1.51633 64.1
29 ∞ 1.56
像面 ∞
各種データ
ズーム比 3.88
広角 中間 望遠
焦点距離 100.47 117.73 390.00
Ｆナンバー 4.60 4.62 8.20
半画角（°） 12.15 10.41 3.18
像高 21.64 21.64 21.64
レンズ全長 191.64 217.51 279.64
BF 21.43 24.11 66.45
d 4 4.76 30.63 92.76
d 9 34.04 35.45 1.27
d15 14.40 14.74 18.28
d17 10.79 10.45 6.91
d22 16.30 14.25 2.82
d25 26.17 24.12 27.40
d27 18.99 21.68 64.01
ズームレンズ群データ
群 始面 焦点距離 レンズ構成長
1 1 210.29 13.27
2 5 -63.56 9.42
3 10 69.29 21.16
4 16 -84.75 1.10
5 18 45.23 12.17
6 23 -58.71 5.25
7 26 -172.11 1.40
（数値実施例３）
単位 mm
面データ
面番号 r d nd νd
1 113.956 2.75 1.67300 38.3
2 67.857 8.69 1.49700 81.5
3 -411.462 1.50
4 ∞ (可変)
5 -159.832 1.50 1.83481 42.7
6 116.910 2.83
7 -68.859 1.50 1.49700 81.5
8 120.055 2.86 1.80810 22.8
9 -307.654 (可変)
10 51.981 6.79 1.49700 81.5
11 -80.876 0.20
12 47.015 6.82 1.54814 45.8
13 -76.634 1.80 1.95375 32.3
14 80.029 5.00
15(絞り) ∞ (可変)
16 -34.414 1.10 1.49700 81.5
17 -89.512 (可変)
18 137.707 4.03 1.68893 31.1
19 -44.597 0.20
20 65.136 6.24 1.49700 81.5
21 -35.706 1.30 2.00069 25.5
22 -168.748 (可変)
23 -1530.333 4.44 1.73800 32.3
24 -29.756 1.20 1.69680 55.5
25 43.002 (可変)
26 -31.740 1.40 1.49700 81.5
27 -56.084 (可変)
28 ∞ 1.34 1.51633 64.1
29 ∞ 1.56
像面 ∞
各種データ
ズーム比 3.84
広角 中間 望遠
焦点距離 101.52 115.89 390.00
Ｆナンバー 4.12 4.08 7.31
半画角（°） 12.03 10.58 3.18
像高 21.64 21.64 21.64
レンズ全長 195.64 221.52 283.64
BF 21.05 19.21 66.45
d 4 4.85 30.73 92.86
d 9 38.00 39.81 1.27
d15 13.65 14.35 20.26
d17 9.92 9.22 3.31
d22 16.30 14.05 2.86
d25 29.72 31.99 34.49
d27 18.62 16.78 64.01
ズームレンズ群データ
群 始面 焦点距離 レンズ構成長
1 1 221.73 12.94
2 5 -69.94 8.69
3 10 80.62 20.61
4 16 -113.24 1.10
5 18 48.51 11.77
6 23 -65.32 5.64
7 26 -149.99 1.40
（数値実施例４）
単位 mm
面データ
面番号 r d nd νd
1 111.412 2.50 1.67300 38.3
2 65.871 7.00 1.49700 81.5
3 -373.228 1.50
4 ∞ (可変)
5 -107.363 1.50 1.95375 32.3
6 95.992 2.71
7 -90.851 1.50 1.49700 81.5
8 67.704 4.00 1.80810 22.8
9 -232.773 (可変)
10 102.155 5.06 1.49700 81.5
11 -81.593 0.20
12 44.034 6.70 1.51823 58.9
13 -93.428 1.80 1.95375 32.3
14 164.987 5.00
15(絞り) ∞ (可変)
16 -43.133 1.10 1.49700 81.5
17 -97.670 (可変)
18 260.201 4.03 1.70154 41.2
19 -46.094 0.20
20 65.583 6.09 1.49700 81.5
21 -37.248 1.30 1.95375 32.3
22 -195.505 (可変)
23 1109.576 3.86 1.65412 39.7
24 -36.880 1.20 1.59282 68.6
25 43.501 (可変)
26 -30.579 1.40 1.49700 81.5
27 -69.098 (可変)
28 ∞ 1.34 1.51633 64.1
29 ∞ 1.55
像面 ∞
各種データ
ズーム比 4.03
広角 中間 望遠
焦点距離 72.00 97.59 290.00
Ｆナンバー 4.02 4.60 6.99
半画角（°） 16.72 12.50 4.27
像高 21.64 21.64 21.64
レンズ全長 184.94 200.34 259.93
BF 21.05 31.96 66.44
d 4 5.27 20.68 80.27
d 9 41.44 33.60 1.30
d15 13.78 17.72 24.54
d17 12.50 8.57 1.74
d22 16.08 12.94 2.91
d25 16.16 16.24 24.09
d27 18.62 29.52 64.00
ズームレンズ群データ
群 始面 焦点距離 レンズ構成長
1 1 213.16 11.00
2 5 -63.33 9.71
3 10 75.26 18.76
4 16 -156.47 1.10
5 18 53.41 11.62
6 23 -88.21 5.06
7 26 -111.72 1.40
（数値実施例５）
単位 mm
面データ
面番号 r d nd νd
1 88.030 2.75 1.74951 35.3
2 60.490 9.50 1.49700 81.5
3 -852.412 1.50
4 ∞ (可変)
5 -164.042 1.50 1.83481 42.7
6 85.556 1.48
7 -2159.839 1.50 1.49700 81.5
8 50.488 3.13 1.80810 22.8
9 145.088 (可変)
10 169.201 4.87 1.49700 81.5
11 -66.171 0.20
12 61.426 6.86 1.51633 64.1
13 -54.278 1.80 1.90043 37.4
14 940.931 5.00
15(絞り) ∞ (可変)
16 -232.216 4.03 1.57501 41.5
17 -48.390 0.20
18 308.786 5.04 1.51742 52.4
19 -34.039 1.30 2.00100 29.1
20 -66.604 (可変)
21 -58.952 1.81 1.89286 20.4
22 -39.667 3.64
23 -45.842 1.20 1.81600 46.6
24 397.671 (可変)
25 -29.775 1.40 1.49700 81.5
26 -76.725 (可変)
27 ∞ 1.34 1.51633 64.1
28 ∞ 1.55
像面 ∞
各種データ
ズーム比 3.84
広角 中間 望遠
焦点距離 101.59 140.00 390.00
Ｆナンバー 4.60 4.86 8.20
半画角（°） 12.02 8.78 3.18
像高 21.64 21.64 21.64
レンズ全長 199.64 237.07 275.41
BF 20.07 22.63 70.41
d 4 3.99 41.43 79.77
d 9 37.62 37.41 1.26
d15 39.48 39.48 39.48
d20 20.62 13.71 2.72
d24 19.15 23.71 23.06
d26 17.64 20.20 67.98
ズームレンズ群データ
群 始面 焦点距離 レンズ構成長
1 1 201.83 13.75
2 5 -68.54 7.61
3 10 87.46 18.73
4 16 83.43 10.57
5 21 -83.98 6.65
6 25 -98.88 1.40
（数値実施例６）
単位 mm
面データ
面番号 r d nd νd
1 140.038 2.70 1.61340 44.3
2 69.874 11.85 1.49700 81.5
3 -466.345 1.50
4 ∞ (可変)
5 -133.713 1.50 1.90043 37.4
6 163.956 2.31
7 -78.894 1.50 1.49700 81.5
8 148.543 3.00 1.80810 22.8
9 -202.679 (可変)
10 48.647 7.01 1.49700 81.5
11 -82.204 0.20
12 63.019 5.96 1.60342 38.0
13 -68.010 1.80 1.95375 32.3
14 95.427 5.00
15(絞り) ∞ (可変)
16 -32.234 1.10 1.49700 81.5
17 -151.375 (可変)
18 345.222 4.03 1.72047 34.7
19 -41.552 0.20
20 70.724 5.77 1.51633 64.1
21 -36.284 1.30 2.00069 25.5
22 -151.263 (可変)
23 184.633 4.75 1.80000 29.8
24 -30.905 1.20 1.80610 40.9
25 46.462 (可変)
26 374.565 1.31 1.49700 81.5
27 677.213 (可変)
28 -60.082 1.40 1.49700 81.5
29 128.625 2.54 1.67270 32.1
30 3928.416 (可変)
31 ∞ 1.34 1.51633 64.1
32 ∞ 1.55
像面 ∞
各種データ
ズーム比 3.84
広角 中間 望遠
焦点距離 101.59 140.40 390.00
Ｆナンバー 4.63 4.84 7.95
半画角（°） 12.02 8.76 3.18
像高 21.64 21.64 21.64
レンズ全長 214.29 260.73 304.29
BF 21.06 27.05 66.44
d 4 5.50 51.94 95.50
d 9 46.47 44.39 1.30
d15 13.45 15.39 22.11
d17 11.00 9.05 2.33
d22 19.67 15.64 7.21
d25 15.40 19.42 27.85
d27 13.83 9.92 13.62
d30 18.62 24.62 64.00
ズームレンズ群データ
群 始面 焦点距離 レンズ構成長
1 1 265.85 16.05
2 5 -81.59 8.31
3 10 81.38 19.98
4 16 -82.66 1.10
5 18 48.73 11.30
6 23 -77.13 5.95
7 26 1683.98 1.31
8 28 -141.45 3.94
(Numerical Example 1)
Unit mm
Surface data surface number rd nd νd
1 112.394 2.75 1.65412 39.7
2 65.388 9.90 1.49700 81.5
3 -402.882 1.50
4 ∞ (variable)
5 -125.993 1.50 1.90043 37.4
6 110.631 2.94
7 -75.566 1.50 1.49700 81.5
8 88.292 3.29 1.80810 22.8
9 -334.236 (variable)
10 49.769 7.30 1.49700 81.5
11 -70.132 0.20
12 60.333 6.39 1.54814 45.8
13 -64.799 1.80 1.95375 32.3
14 146.189 5.00
15 (aperture) ∞ (variable)
16 -32.071 1.10 1.49700 81.5
17 -589.673 (variable)
18 148.720 4.03 1.64769 33.8
19 -42.153 0.20
20 58.751 6.45 1.49700 81.5
21 -37.587 1.30 2.00069 25.5
22 -149.927 (variable)
23 171.353 4.56 1.80000 29.8
24 -34.552 1.20 1.78590 44.2
25 43.333 (variable)
26 -35.871 1.40 1.49700 81.5
27 -73.198 (variable)
28 ∞ 1.34 1.51633 64.1
29 ∞ 1.56
Image plane ∞
Various data Zoom ratio 3.85
Wide Angle Intermediate Telephoto Focal Length 101.32 119.51 390.00
F number 4.60 4.62 8.20
Half angle of view (°) 12.05 10.26 3.18
Image height 21.64 21.64 21.64
Lens total length 206.13 233.59 294.63
BF 21.63 22.83 66.45
d 4 6.20 33.65 94.70
d 9 36.10 37.54 1.29
d15 14.92 15.08 16.52
d17 13.14 12.98 11.55
d22 16.86 14.24 3.36
d25 32.97 32.95 36.46
d27 19.19 20.40 64.01
Zoom lens group data group Starting plane Focal length Lens configuration length
1 1 215.80 14.15
2 5 -63.35 9.23
3 10 68.12 20.70
4 16 -68.29 1.10
5 18 45.45 11.98
6 23 -78.20 5.76
7 26 -143.32 1.40
(Numerical Example 2)
Unit: mm
Surface data surface number rd nd νd
1 104.135 2.75 1.67300 38.3
2 63.657 9.02 1.49700 81.5
3 -467.470 1.50
4 ∞ (variable)
5 -179.352 1.50 1.88100 40.1
6 101.553 3.41
7 -56.081 1.50 1.49700 81.5
8 137.281 3.00 1.80810 22.8
9 -187.787 (variable)
10 44.201 7.53 1.49700 81.5
11 -77.974 0.20
12 56.689 6.63 1.54814 45.8
13 -63.549 1.80 1.95375 32.3
14 116.096 5.00
15 (aperture) ∞ (variable)
16 -29.839 1.10 1.49700 81.5
17 -103.584 (variable)
18 110.253 4.03 1.67270 32.1
19 -41.917 0.20
20 61.667 6.64 1.49700 81.5
21 -33.033 1.30 2.00069 25.5
22 -160.251 (variable)
23 -1471.792 4.05 1.71736 29.5
24 -33.018 1.20 1.69680 55.5
25 40.625 (variable)
26 -31.668 1.40 1.49700 81.5
27 -51.022 (variable)
28 ∞ 1.34 1.51633 64.1
29 ∞ 1.56
Image plane ∞
Various data Zoom ratio 3.88
Wide Angle Intermediate Telephoto Focal Length 100.47 117.73 390.00
F number 4.60 4.62 8.20
Half angle of view (°) 12.15 10.41 3.18
Image height 21.64 21.64 21.64
Lens total length 191.64 217.51 279.64
BF 21.43 24.11 66.45
d 4 4.76 30.63 92.76
d 9 34.04 35.45 1.27
d15 14.40 14.74 18.28
d17 10.79 10.45 6.91
d22 16.30 14.25 2.82
d25 26.17 24.12 27.40
d27 18.99 21.68 64.01
Zoom lens group data group Starting surface Focal length Lens length
1 1 210.29 13.27
2 5 -63.56 9.42
3 10 69.29 21.16
4 16 -84.75 1.10
5 18 45.23 12.17
6 23 -58.71 5.25
7 26 -172.11 1.40
(Numerical Example 3)
Unit: mm
Surface data surface number rd nd νd
1 113.956 2.75 1.67300 38.3
2 67.857 8.69 1.49700 81.5
3 -411.462 1.50
4 ∞ (variable)
5 -159.832 1.50 1.83481 42.7
6 116.910 2.83
7 -68.859 1.50 1.49700 81.5
8 120.055 2.86 1.80810 22.8
9 -307.654 (variable)
10 51.981 6.79 1.49700 81.5
11 -80.876 0.20
12 47.015 6.82 1.54814 45.8
13 -76.634 1.80 1.95375 32.3
14 80.029 5.00
15 (aperture) ∞ (variable)
16 -34.414 1.10 1.49700 81.5
17 -89.512 (variable)
18 137.707 4.03 1.68893 31.1
19 -44.597 0.20
20 65.136 6.24 1.49700 81.5
21 -35.706 1.30 2.00069 25.5
22 -168.748 (variable)
23 -1530.333 4.44 1.73800 32.3
24 -29.756 1.20 1.69680 55.5
25 43.002 (variable)
26 -31.740 1.40 1.49700 81.5
27 -56.084 (variable)
28 ∞ 1.34 1.51633 64.1
29 ∞ 1.56
Image plane ∞
Various data Zoom ratio 3.84
Wide Angle Intermediate Telephoto Focal Length 101.52 115.89 390.00
F number 4.12 4.08 7.31
Half angle of view (°) 12.03 10.58 3.18
Image height 21.64 21.64 21.64
Lens total length 195.64 221.52 283.64
BF 21.05 19.21 66.45
d 4 4.85 30.73 92.86
d 9 38.00 39.81 1.27
d15 13.65 14.35 20.26
d17 9.92 9.22 3.31
d22 16.30 14.05 2.86
d25 29.72 31.99 34.49
d27 18.62 16.78 64.01
Zoom lens group data group Starting surface Focal length Lens length
1 1 221.73 12.94
2 5 -69.94 8.69
3 10 80.62 20.61
4 16 -113.24 1.10
5 18 48.51 11.77
6 23 -65.32 5.64
7 26 -149.99 1.40
(Numerical Example 4)
Unit: mm
Surface data surface number rd nd νd
1 111.412 2.50 1.67300 38.3
2 65.871 7.00 1.49700 81.5
3 -373.228 1.50
4 ∞ (variable)
5 -107.363 1.50 1.95375 32.3
6 95.992 2.71
7 -90.851 1.50 1.49700 81.5
8 67.704 4.00 1.80810 22.8
9 -232.773 (variable)
10 102.155 5.06 1.49700 81.5
11 -81.593 0.20
12 44.034 6.70 1.51823 58.9
13 -93.428 1.80 1.95375 32.3
14 164.987 5.00
15 (aperture) ∞ (variable)
16 -43.133 1.10 1.49700 81.5
17 -97.670 (variable)
18 260.201 4.03 1.70154 41.2
19 -46.094 0.20
20 65.583 6.09 1.49700 81.5
21 -37.248 1.30 1.95375 32.3
22 -195.505 (variable)
23 1109.576 3.86 1.65412 39.7
24 -36.880 1.20 1.59282 68.6
25 43.501 (variable)
26 -30.579 1.40 1.49700 81.5
27 -69.098 (variable)
28 ∞ 1.34 1.51633 64.1
29 ∞ 1.55
Image plane ∞
Various data Zoom ratio 4.03
Wide Angle Intermediate Telephoto Focal Length 72.00 97.59 290.00
F number 4.02 4.60 6.99
Half angle of view (°) 16.72 12.50 4.27
Image height 21.64 21.64 21.64
Lens total length 184.94 200.34 259.93
BF 21.05 31.96 66.44
d 4 5.27 20.68 80.27
d 9 41.44 33.60 1.30
d15 13.78 17.72 24.54
d17 12.50 8.57 1.74
d22 16.08 12.94 2.91
d25 16.16 16.24 24.09
d27 18.62 29.52 64.00
Zoom lens group data group Starting surface Focal length Lens length
1 1 213.16 11.00
2 5 -63.33 9.71
3 10 75.26 18.76
4 16 -156.47 1.10
5 18 53.41 11.62
6 23 -88.21 5.06
7 26 -111.72 1.40
(Numerical Example 5)
Unit: mm
Surface data surface number rd nd νd
1 88.030 2.75 1.74951 35.3
2 60.490 9.50 1.49700 81.5
3 -852.412 1.50
4 ∞ (variable)
5 -164.042 1.50 1.83481 42.7
6 85.556 1.48
7 -2159.839 1.50 1.49700 81.5
8 50.488 3.13 1.80810 22.8
9 145.088 (variable)
10 169.201 4.87 1.49700 81.5
11 -66.171 0.20
12 61.426 6.86 1.51633 64.1
13 -54.278 1.80 1.90043 37.4
14 940.931 5.00
15 (aperture) ∞ (variable)
16 -232.216 4.03 1.57501 41.5
17 -48.390 0.20
18 308.786 5.04 1.51742 52.4
19 -34.039 1.30 2.00100 29.1
20 -66.604 (variable)
21 -58.952 1.81 1.89286 20.4
22 -39.667 3.64
23 -45.842 1.20 1.81600 46.6
24 397.671 (variable)
25 -29.775 1.40 1.49700 81.5
26 -76.725 (variable)
27 ∞ 1.34 1.51633 64.1
28 ∞ 1.55
Image plane ∞
Various data Zoom ratio 3.84
Wide Angle Intermediate Telephoto Focal Length 101.59 140.00 390.00
F number 4.60 4.86 8.20
Half angle of view (°) 12.02 8.78 3.18
Image height 21.64 21.64 21.64
Lens total length 199.64 237.07 275.41
BF 20.07 22.63 70.41
d 4 3.99 41.43 79.77
d 9 37.62 37.41 1.26
d15 39.48 39.48 39.48
d20 20.62 13.71 2.72
d24 19.15 23.71 23.06
d26 17.64 20.20 67.98
Zoom lens group data group Starting surface Focal length Lens length
1 1 201.83 13.75
2 5 -68.54 7.61
3 10 87.46 18.73
4 16 83.43 10.57
5 21 -83.98 6.65
6 25 -98.88 1.40
(Numerical Example 6)
Unit: mm
Surface data surface number rd nd νd
1 140.038 2.70 1.61340 44.3
2 69.874 11.85 1.49700 81.5
3 -466.345 1.50
4 ∞ (variable)
5 -133.713 1.50 1.90043 37.4
6 163.956 2.31
7 -78.894 1.50 1.49700 81.5
8 148.543 3.00 1.80810 22.8
9 -202.679 (variable)
10 48.647 7.01 1.49700 81.5
11 -82.204 0.20
12 63.019 5.96 1.60342 38.0
13 -68.010 1.80 1.95375 32.3
14 95.427 5.00
15 (aperture) ∞ (variable)
16 -32.234 1.10 1.49700 81.5
17 -151.375 (variable)
18 345.222 4.03 1.72047 34.7
19 -41.552 0.20
20 70.724 5.77 1.51633 64.1
21 -36.284 1.30 2.00069 25.5
22 -151.263 (variable)
23 184.633 4.75 1.80000 29.8
24 -30.905 1.20 1.80610 40.9
25 46.462 (variable)
26 374.565 1.31 1.49700 81.5
27 677.213 (variable)
28 -60.082 1.40 1.49700 81.5
29 128.625 2.54 1.67270 32.1
30 3928.416 (variable)
31 ∞ 1.34 1.51633 64.1
32 ∞ 1.55
Image plane ∞
Various data Zoom ratio 3.84
Wide Angle Intermediate Telephoto Focal Length 101.59 140.40 390.00
F number 4.63 4.84 7.95
Half angle of view (°) 12.02 8.76 3.18
Image height 21.64 21.64 21.64
Lens total length 214.29 260.73 304.29
BF 21.06 27.05 66.44
d 4 5.50 51.94 95.50
d 9 46.47 44.39 1.30
d15 13.45 15.39 22.11
d17 11.00 9.05 2.33
d22 19.67 15.64 7.21
d25 15.40 19.42 27.85
d27 13.83 9.92 13.62
d30 18.62 24.62 64.00
Zoom lens group data group Starting surface Focal length Lens length
1 1 265.85 16.05
2 5 -81.59 8.31
3 10 81.38 19.98
4 16 -82.66 1.10
5 18 48.73 11.30
6 23 -77.13 5.95
7 26 1683.98 1.31
8 28 -141.45 3.94
（撮像装置）
次に、本発明のズームレンズを撮像光学系として用いた光学機器としてのデジタルスチルカメラ（撮像装置）の実施例について、図２５を用いて説明する。図２５において、３０はカメラ本体、３１は実施例１乃至６で説明したいずれかのズームレンズによって構成された撮影光学系である。３２はカメラ本体に内蔵され、撮影光学系３１によって形成された光学像を受光して光電変換するＣＣＤセンサやＣＭＯＳセンサ等の固体撮像素子（光電変換素子）である。カメラ本体１０はクイックターンミラーを有する所謂一眼レフカメラでも良いし、クイックターンミラーを有さない所謂ミラーレスカメラでも良い。
(imaging device)
Next, an embodiment of a digital still camera (imaging device) as an optical device using the zoom lens of the present invention as an imaging optical system will be described using FIG. 25. In FIG. 25, 30 is a camera body, and 31 is a photographing optical system constituted by any of the zoom lenses described in Examples 1 to 6. 32 is a solid-state imaging device (photoelectric conversion device), such as a CCD sensor or a CMOS sensor, which is built into the camera body and receives an optical image formed by the photographing optical system 31 and converts it photoelectrically. The camera body 10 may be a so-called single-lens reflex camera with a quick turn mirror, or a so-called mirrorless camera without a quick turn mirror.
このように本発明のズームレンズをデジタルスチルカメラ等の撮像装置に適用することにより、レンズが小型である撮像装置を得ることができる。 As described above, by applying the zoom lens of the present invention to an imaging device such as a digital still camera, it is possible to obtain an imaging device with a compact lens.
以上、本発明の好ましい実施形態について説明したが、本発明はこれらの実施形態に限定されず、その要旨の範囲内で種々の変形及び変更が可能である。また設計機能を考慮した構成であれば、それを限定するものではない。 Although preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and changes can be made within the scope of the invention. Further, as long as the configuration takes design functions into consideration, the configuration is not limited thereto.
Ｌ１ ： 第１レンズ群
Ｌ２ ： 第２レンズ群
L1: 1st lens group L2: 2nd lens group
Claims (15)
前記第１レンズ群は、前記物体側から前記像側へ順に、１枚の負レンズと１枚の正レンズから構成され、
前記後続群のうち、最も像側に配置されたレンズ群Ｒｎは負の屈折力を有し、
前記第１レンズ群に含まれる前記負レンズの異常分散性をΔθｇＦ１ｎ、前記負レンズのアッベ数および部分分散比を各々νｄ１ｎ、θｇ１ｎ、前記第１レンズ群の最も物体側のレンズ面の曲率、および最も像側のレンズ面の曲率を各々Ｒ１ｏｂｊ、Ｒ１ｉｍｇ、広角端および望遠端のバックフォーカスを各々ＢＦｗ、ＢＦｔ、前記レンズ群Ｒｎの焦点距離をｆＲｎ、前記第１レンズ群の焦点距離をｆ１としたとき、
ΔθｇＦ１ｎ＜０
ΔθｇＦ１ｎ＝θｇＦ１ｎ－（－１．６６５×１０－７×νｄ１ｎ３＋５．２１３Ｅ－５×νｄ１ｎ２－５．６５６×１０－３×νｄ１ｎ＋０．７２６８）
－０．９＜（Ｒ１ｏｂｊ＋Ｒ１ｉｍｇ）／（Ｒ１ｏｂｊ－Ｒ１ｉｍｇ）＜０
２．３＜ＢＦｔ／ＢＦｗ＜４．５
－１．２０＜ｆＲｎ／ｆ１＜－０．４５
なる条件式を満足することを特徴とするズームレンズ。 Consisting of a first lens group with positive refractive power, a second lens group with negative refractive power, and a subsequent lens group including a plurality of lens groups, which are arranged in order from the object side to the image side. A zoom lens in which the distance between matching lens groups changes,
The first lens group is composed of one negative lens and one positive lens in order from the object side to the image side,
Among the subsequent groups, the lens group Rn disposed closest to the image side has a negative refractive power,
The anomalous dispersion of the negative lens included in the first lens group is ΔθgF1n, the Abbe number and partial dispersion ratio of the negative lens are νd1n and θg1n, respectively, the curvature of the lens surface closest to the object side of the first lens group, and The curvature of the lens surface closest to the image side is R1obj and R1img, the back focus at the wide-angle end and the telephoto end is BFw and BFt, respectively, the focal length of the lens group Rn is fRn, and the focal length of the first lens group is f1. When,
ΔθgF1n<0
ΔθgF1n=θgF1n-(-1.665×10 −7 ×νd1n 3 +5.213E−5×νd1n 2 −5.656×10 −3 ×νd1n+0.7268)
-0.9<(R1obj+R1img)/(R1obj-R1img)<0
2.3<BFt/BFw<4.5
-1.20<fRn/f1<-0.45
A zoom lens characterized by satisfying the following conditional expression.
ΔθｇＦＲｎ＞０．０１
なる条件式を満足することを特徴とすることを特徴とする請求項１に記載のズームレンズ。 When the anomalous dispersion of the glass material of the negative lens included in the lens group Rn is ΔθgFRn,
ΔθgFRn>0.01
2. The zoom lens according to claim 1, wherein the zoom lens satisfies the following conditional expression.
－４．０＜ｆ１／ｆ２＜－２．０
なる条件式を満足することを特徴とすることを特徴とする請求項１または２に記載のズームレンズ。 When the focal length of the second lens group is f2,
-4.0<f1/f2<-2.0
3. The zoom lens according to claim 1, wherein the zoom lens satisfies the following conditional expression.
－０．５０＜Ｍ１／ｆ１＜－０．２５
なる条件式を満足することを特徴とする請求項１から３のいずれか一項に記載のズームレンズ。 When the amount of movement of the first lens group from the wide-angle end to the telephoto end is M1,
-0.50<M1/f1<-0.25
4. The zoom lens according to claim 1, wherein the zoom lens satisfies the following conditional expression.
１．２＜（Ｒ１ｉｍｇ＋Ｒ２ｏｂｊ）／（Ｒ１ｉｍｇ－Ｒ２ｏｂｊ）＜３．５
なる条件式を満足することを特徴とすることを請求項１から４のいずれか一項に記載のズームレンズ。 When the curvature of the lens surface closest to the object side of the second lens group is R2obj,
1.2<(R1img+R2obj)/(R1img-R2obj)<3.5
5. The zoom lens according to claim 1, wherein the zoom lens satisfies the following conditional expression.
前記第１レンズ群は、前記物体側から前記像側へ順に、１枚の負レンズと１枚の正レンズから構成され、
前記第１レンズ群に含まれる前記負レンズの異常分散性をΔθｇＦ１ｎ、前記負レンズのアッベ数および部分分散比を各々νｄ１ｎ、θｇＦ１ｎ、前記第１レンズ群の最も物体側のレンズ面の曲率、および最も像側のレンズ面の曲率を各々Ｒ１ｏｂｊ、Ｒ１ｉｍｇ、広角端および望遠端のバックフォーカスを各々ＢＦｗ、ＢＦｔ、前記第２レンズ群の最も物体側のレンズ面の曲率をＲ２ｏｂｊとしたとき、
ΔθｇＦ１ｎ＜０
ΔθｇＦ１ｎ＝θｇＦ１ｎ－（－１．６６５×１０-7×νｄ１ｎ3＋５．２１３×１０－５×νｄ１ｎ2－５．６５６×１０－３－３×νｄ１ｎ＋０．７２６８）
－０．９＜（Ｒ１ｏｂｊ＋Ｒ１ｉｍｇ）／（Ｒ１ｏｂｊ－Ｒ１ｉｍｇ）＜０
２．３＜ＢＦｔ／ＢＦｗ＜４．５
１．４＜（Ｒ１ｉｍｇ＋Ｒ２ｏｂｊ）／（Ｒ１ｉｍｇ－Ｒ２ｏｂｊ）＜３．５
なる条件式を満足することを特徴とするズームレンズ。 It has a first lens group having a positive refractive power and a second lens group having a negative refractive power, which are arranged in order from the object side to the image side, and the distance between adjacent lens groups changes during zooming. It is a zoom lens,
The first lens group is composed of one negative lens and one positive lens in order from the object side to the image side,
The anomalous dispersion of the negative lens included in the first lens group is ΔθgF1n, the Abbe number and partial dispersion ratio of the negative lens are νd1n and θgF1n, respectively, the curvature of the lens surface closest to the object side of the first lens group, and When the curvature of the lens surface closest to the image side is R1obj and R1img, the back focus at the wide-angle end and the telephoto end is BFw and BFt, respectively, and the curvature of the lens surface closest to the object side of the second lens group is R2obj,
ΔθgF1n<0
ΔθgF1n=θgF1n-(-1.665×10 -7 ×νd1n 3 +5.213×10 −5 ×νd1n 2 −5.656×10 −3 −3×νd1n+0.7268)
-0.9<(R1obj+R1img)/(R1obj-R1img)<0
2.3<BFt/BFw<4.5
1.4<(R1img+R2obj)/(R1img-R2obj)<3.5
A zoom lens characterized by satisfying the following conditional expression.
前記２つのレンズ群は、各々異なる方向に移動することを特徴とする請求項１乃至５のいずれか一項に記載のズームレンズ。 The subsequent group includes two lens groups that move when focusing from infinity to a short distance,
The zoom lens according to any one of claims 1 to 5 , wherein the two lens groups move in different directions.
前記第１レンズ群は、前記物体側から前記像側へ順に、１枚の負レンズと１枚の正レンズから構成され、
前記後続群は、無限遠から近距離へのフォーカス時に移動する２つのレンズ群を有し、該２つのレンズ群は、無限遠から近距離へのフォーカス時に各々異なる方向に移動し、
前記第１レンズ群に含まれる前記負レンズの異常分散性をΔθｇＦ１ｎ、前記負レンズのアッベ数および部分分散比を各々νｄ１ｎ、θｇＦ１ｎ、前記第１レンズ群の最も物体側のレンズ面の曲率、および最も像側のレンズ面の曲率を各々Ｒ１ｏｂｊ、Ｒ１ｉｍｇ、広角端および望遠端のバックフォーカスを各々ＢＦｗ、ＢＦｔとしたとき、
ΔθｇＦ１ｎ＜０
ΔθｇＦ１ｎ＝θｇＦ１ｎ－（－１．６６５×１０－７×νｄ１ｎ３＋５．２１３×１０－５×νｄ１ｎ２－５．６５６×１０－３×νｄ１ｎ＋０．７２６８）
－０．９＜（Ｒ１ｏｂｊ＋Ｒ１ｉｍｇ）／（Ｒ１ｏｂｊ－Ｒ１ｉｍｇ）＜０
２．３＜ＢＦｔ／ＢＦｗ＜４．５
なる条件式を満足することを特徴とするズームレンズ。 Consisting of a first lens group with positive refractive power, a second lens group with negative refractive power, and a subsequent lens group including a plurality of lens groups, which are arranged in order from the object side to the image side. A zoom lens in which the distance between matching lens groups changes,
The first lens group is composed of one negative lens and one positive lens in order from the object side to the image side,
The subsequent group includes two lens groups that move when focusing from infinity to a short distance, and the two lens groups move in different directions when focusing from infinity to a short distance,
The anomalous dispersion of the negative lens included in the first lens group is ΔθgF1n, the Abbe number and partial dispersion ratio of the negative lens are νd1n and θgF1n, respectively, the curvature of the lens surface closest to the object side of the first lens group, and When the curvature of the lens surface closest to the image side is R1obj and R1img, and the back focus at the wide-angle end and telephoto end is BFw and BFt, respectively,
ΔθgF1n<0
ΔθgF1n=θgF1n-(-1.665×10 −7 ×νd1n 3 +5.213×10 −5 ×νd1n 2 −5.656×10 −3 ×νd1n+0.7268)
-0.9<(R1obj+R1img)/(R1obj-R1img)<0
2.3<BFt/BFw<4.5
A zoom lens characterized by satisfying the following conditional expression.
前記第１レンズ群は、前記物体側から前記像側へ順に、１枚の負レンズと１枚の正レンズから構成され、
前記第１レンズ群に含まれる前記負レンズの異常分散性をΔθｇＦ１ｎ、前記負レンズのアッベ数および部分分散比を各々νｄ１ｎ、θｇＦ１ｎ、前記第１レンズ群の最も物体側のレンズ面の曲率、および最も像側のレンズ面の曲率を各々Ｒ１ｏｂｊ、Ｒ１ｉｍｇ、広角端および望遠端のバックフォーカスを各々ＢＦｗ、ＢＦｔとしたとき、
ΔθｇＦ１ｎ＜０
ΔθｇＦ１ｎ＝θｇＦ１ｎ－（－１．６６５Ｅ－７×νｄ１ｎ^３＋５．２１３Ｅ－５×νｄ１ｎ^２－５．６５６Ｅ－３×νｄ１ｎ＋０．７２６８）
－０．９＜（Ｒ１ｏｂｊ＋Ｒ１ｉｍｇ）／（Ｒ１ｏｂｊ－Ｒ１ｉｍｇ）＜０
２．３＜ＢＦｔ／ＢＦｗ＜４．５
なる条件式を満足することを特徴とするズームレンズ。 A first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, and a fourth lens group having a negative refractive power, which are arranged in order from the object side to the image side. The lens group consists of a fifth lens group with positive refractive power, a sixth lens group with negative refractive power, a seventh lens group with positive refractive power, and an eighth lens group with negative refractive power, and when zooming, adjacent lenses A zoom lens in which the distance between groups changes,
The first lens group is composed of one negative lens and one positive lens in order from the object side to the image side,
The anomalous dispersion of the negative lens included in the first lens group is ΔθgF1n, the Abbe number and partial dispersion ratio of the negative lens are νd1n and θgF1n, respectively, the curvature of the lens surface closest to the object side of the first lens group, and When the curvature of the lens surface closest to the image side is R1obj and R1img, and the back focus at the wide-angle end and telephoto end is BFw and BFt, respectively,
ΔθgF1n<0
ΔθgF1n=θgF1n-(-1.665E-7×νd1n^3+5.213E-5×νd1n^2-5.656E-3×νd1n+0.7268)
-0.9<(R1obj+R1img)/(R1obj-R1img)<0
2.3<BFt/BFw<4.5
A zoom lens characterized by satisfying the following conditional expression.
前記ズームレンズによって形成された像を受光する撮像素子と、を有することを特徴とする光学機器。 A zoom lens according to any one of claims 1 to 13,
An optical device comprising: an image sensor that receives an image formed by the zoom lens.
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| JP2007322669A (en) | 2006-05-31 | 2007-12-13 | Eastman Kodak Co | Zoom lens and imaging apparatus |
| JP2009128606A (en) | 2007-11-22 | 2009-06-11 | Nikon Corp | Zoom lens, optical equipment with mounted zoom lens and imaging method |
| JP2016143012A (en) | 2015-02-05 | 2016-08-08 | Hoya株式会社 | Zoom lens system |
| JP2019020679A (en) | 2017-07-21 | 2019-02-07 | キヤノン株式会社 | Zoom lens and imaging apparatus having the same |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007322669A (en) | 2006-05-31 | 2007-12-13 | Eastman Kodak Co | Zoom lens and imaging apparatus |
| JP2009128606A (en) | 2007-11-22 | 2009-06-11 | Nikon Corp | Zoom lens, optical equipment with mounted zoom lens and imaging method |
| JP2016143012A (en) | 2015-02-05 | 2016-08-08 | Hoya株式会社 | Zoom lens system |
| JP2019020679A (en) | 2017-07-21 | 2019-02-07 | キヤノン株式会社 | Zoom lens and imaging apparatus having the same |
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