JP2007093773A - Zoom lens and image pickup device including the same - Google Patents
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Abstract
Description
本発明はビデオカメラ、銀塩写真用カメラ、放送用カメラ、そしてデジタルスチルカメラ等に好適なズームレンズ及びそれを有する撮像装置に関する。 The present invention relates to a zoom lens suitable for a video camera, a silver salt photography camera, a broadcast camera, a digital still camera, and the like, and an imaging apparatus having the same.
近年、固体撮像素子を用いたビデオカメラ、デジタルスチルカメラ、放送用カメラ、そして銀塩フィルムを用いたスチルカメラ等の撮像装置においては、高機能化とともに装置全体の小型化がなされている。 In recent years, imaging devices such as a video camera using a solid-state imaging device, a digital still camera, a broadcasting camera, and a still camera using a silver halide film have been improved in function and downsized as a whole.
そしてそれに伴って、これらに用いる撮影光学系としては、レンズ全長が短くコンパクトでしかも高解像力のズームレンズが要求されている。 Along with this, as a photographing optical system used for these, a zoom lens having a short overall lens length and being compact and having a high resolution is required.
一眼レフカメラ等の撮像装置に用いられるバックフォーカスの長いズームレンズとして物体側より像側へ順に、正、負、正、正の屈折力のレンズ群より成る４群ズームレンズが知られている。 As a zoom lens having a long back focus used in an imaging apparatus such as a single-lens reflex camera, a four-group zoom lens including a lens group having positive, negative, positive, and positive refractive powers in order from the object side to the image side is known.
このタイプの４群ズームレンズにおいて、広角端から望遠端へのズーミングに際し各レンズ群を物体側へ移動させ、高ズーム比でありながらコンパクト化を図った４群ズームレンズが知られている。（例えば、特許文献１）。 In this type of four-group zoom lens, there is known a four-group zoom lens in which each lens group is moved to the object side during zooming from the wide-angle end to the telephoto end to achieve compactness while maintaining a high zoom ratio. (For example, patent document 1).
また、物体側より順に正、負、正、そして正の屈折力のレンズ群を持つ４つのレンズ群より成り、非球面レンズを使用して構成レンズ枚数を少なくした、コンパクトで広画角のズーム変倍比３〜３．５倍程度の４群ズームレンズが知られている（例えば特許文献２）。
前述した撮像装置に用いるズームレンズでは、レンズ系全体の小型化を図って且つ所定のズーム比を有しつつ、全ズーム範囲にわたり良好なる光学性能を有していることが重要である。このためには、ズーミングに伴う各レンズ群の移動条件や各レンズ群の屈折力、各レンズ群のレンズ構成等を適切に設定する必要がある。例えばズームレンズの小型化に関しては、各レンズ群の屈折力を強めればズーミングにおける各レンズ群の移動量が少なくなり、レンズ全長の短縮化が可能となる。 In the zoom lens used in the imaging apparatus described above, it is important that the entire lens system is miniaturized and has a predetermined zoom ratio and has good optical performance over the entire zoom range. For this purpose, it is necessary to appropriately set the movement condition of each lens group accompanying zooming, the refractive power of each lens group, the lens configuration of each lens group, and the like. For example, regarding the miniaturization of a zoom lens, if the refractive power of each lens group is increased, the amount of movement of each lens group during zooming is reduced, and the overall length of the lens can be shortened.
しかしながら、各レンズ群の屈折力を単に強めるとズーミングに伴う収差変動が大きくなり、これを良好に補正するのが難しくなってくる。 However, if the refracting power of each lens unit is simply increased, aberration fluctuations associated with zooming increase, and it becomes difficult to correct this well.
また、近年デジタル一眼レフカメラにおいては、被写体像を記録する撮像素子に様々なフォーマット（サイズ）のものが用いられている。 In recent years, in digital single-lens reflex cameras, sensors having various formats (sizes) are used as image sensors for recording a subject image.
特にコンパクトを狙った一眼レフカメラでは、撮像素子に小型のものが使用されている。 In particular, in a single-lens reflex camera aiming at compactness, a small-sized image pickup element is used.
３５ｍｍフィルムフォーマットより小さい画面サイズの撮像素子を使用したカメラでは、同じ焦点距離の撮影レンズを使用しても撮影画界が狭くなる。このため３５ｍｍフィルムフォーマットと同じ画界を得るためにはより焦点距離の短い撮影レンズを必要とする。 In a camera using an image sensor having a screen size smaller than the 35 mm film format, the shooting field is narrowed even if a shooting lens having the same focal length is used. For this reason, in order to obtain the same field of view as the 35 mm film format, a photographing lens having a shorter focal length is required.
又、一眼レフカメラでは、被写体からの撮影光をクイックリターンミラーで折り曲げファインダー光学系に導いている。このため撮影レンズの最終面から撮像面までの間（バックフォーカス）に十分な空間を必要とする。 In a single-lens reflex camera, photographing light from a subject is bent by a quick return mirror and guided to a finder optical system. For this reason, a sufficient space is required between the final surface of the photographing lens and the imaging surface (back focus).
そのため一眼レフカメラ用の撮影レンズのうち焦点距離の短い撮影レンズでは、物体側から順に負、正の屈折力のレンズ群配置、所謂レトロフォーカスタイプの光学配置としている。これによって光学系の主点位置が撮影レンズの最終面よりも像面側に存在するようにしている。
前述の特許文献１、２のズームレンズでも、広角端では第１、第２レンズ群が合成で負の屈折力となり、第３、第４レンズ群が合成で正の屈折力配置となって全体として略レトロフォーカスタイプの光学系としている。
For this reason, among photographic lenses for single-lens reflex cameras, photographic lenses with a short focal length are arranged in order from the object side in negative and positive refractive power lens groups, so-called retrofocus type optical arrangements. As a result, the principal point position of the optical system is located on the image plane side with respect to the final surface of the photographing lens.
Even in the zoom lenses disclosed in Patent Documents 1 and 2, the first and second lens groups are combined with negative refractive power at the wide-angle end, and the third and fourth lens groups are combined with positive refractive power and are arranged as a whole. As a substantially retro-focus type optical system.
これらの光学系を記録画面サイズが３５ｍｍフィルムフォーマットの０．６〜０．７倍程度の大きさになる撮像素子（所謂ＡＰＳサイズ）に適用するには、引用文献１〜２の光学系をそのまま比例縮小することが考えられる。しかしながら単純に縮小しただけでは、撮影画角は同等になるが、前述のクイックリターンミラー機構を入れるにはバックフォーカスが足りなくなってくる。 In order to apply these optical systems to an image sensor (so-called APS size) in which the recording screen size is about 0.6 to 0.7 times that of the 35 mm film format, the optical systems of the cited references 1 and 2 are used as they are. Proportional reduction can be considered. However, if the image is simply reduced, the field angle of view is the same, but the back focus is insufficient for the quick return mirror mechanism described above.
本発明は、レンズ構成が簡易でコンパクトでありながら十分なバックフォーカスを有し、同時に全ズーム領域にわたり高い光学性能を達成したズームレンズの提供を目的とする。 SUMMARY OF THE INVENTION An object of the present invention is to provide a zoom lens that has a simple and compact lens configuration, has sufficient back focus, and at the same time achieves high optical performance over the entire zoom range.
本発明のズームレンズは、物体側より像側へ順に、正の屈折力の第１レンズ群、負の屈折力の第２レンズ群、正の屈折力の第３レンズ群、正の屈折力の第４レンズ群を有し、広角端に比べ望遠端での、該第１レンズ群と第２レンズ群の間隔が大きく、該第２レンズ群と第３レンズ群の間隔が小さくなるように、各レンズ群のうち少なくとも該第１、第３、第４レンズ群が光軸上を物体側へ単調に移動するズームレンズにおいて、
ｉを物体側から像側への順番とするとき、該第ｉレンズ群の焦点距離をｆｉ、広角端における全系の焦点距離をｆｗとするとき、
４．０ ＜ ｆ１／ｆｗ ＜ ７．０
２．０ ＜ ｆ３／ｆｗ ＜ ５．０
なる条件を満足することを特徴ととしている。
The zoom lens according to the present invention includes, 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, a third lens group having a positive refractive power, and a positive lens having a positive refractive power. Having a fourth lens group, the distance between the first lens group and the second lens group at the telephoto end is larger than the wide angle end, and the distance between the second lens group and the third lens group is smaller; In a zoom lens in which at least the first, third, and fourth lens groups of each lens group move monotonously on the optical axis toward the object side,
When i is the order from the object side to the image side, the focal length of the i-th lens group is fi, and the focal length of the entire system at the wide angle end is fw.
4.0 <f1 / fw <7.0
2.0 <f3 / fw <5.0
It is characterized by satisfying the following conditions.
本発明によれば、レンズ構成が簡易でコンパクトでありながら十分なバックフォーカスを有し、同時に全ズーム領域にわたり高い光学性能を達成したズームレンズが得られる。 According to the present invention, it is possible to obtain a zoom lens that has a simple and compact lens configuration, has sufficient back focus, and at the same time achieves high optical performance over the entire zoom range.
以下、本発明のズームレンズ及びそれを有する撮像装置の実施例について説明する。 Embodiments of the zoom lens of the present invention and an image pickup apparatus having the same will be described below.
図１は本発明の実施例１のズームレンズの広角端（短焦点距離端）におけるレンズ断面図、図２、図３はそれぞれ実施例１のズームレンズの広角端、望遠端（長焦点距離端）における収差図である。 FIG. 1 is a lens cross-sectional view at the wide-angle end (short focal length end) of the zoom lens according to Embodiment 1 of the present invention. FIGS. 2 and 3 are a wide-angle end and a telephoto end (long focal length end) of the zoom lens according to Embodiment 1, respectively. FIG.
実施例１はズーム比３．４２、開口比４．１〜５．９程度のズームレンズである。 Example 1 is a zoom lens having a zoom ratio of 3.42 and an aperture ratio of about 4.1 to 5.9.
図４は本発明の実施例２のズームレンズの広角端におけるレンズ断面図、図５、図６はそれぞれ実施例２のズームレンズの広角端、望遠端における収差図である。実施例２はズーム比３．４、開口比４．１〜５．６程度のズームレンズである。 FIG. 4 is a lens cross-sectional view at the wide-angle end of the zoom lens according to Embodiment 2 of the present invention, and FIGS. 5 and 6 are aberration diagrams at the wide-angle end and telephoto end of the zoom lens according to Embodiment 2, respectively. The second embodiment is a zoom lens having a zoom ratio of about 3.4 and an aperture ratio of about 4.1 to 5.6.
図７は本発明の実施例３のズームレンズの広角端におけるレンズ断面図、図８、図９はそれぞれ実施例３のズームレンズの広角端、望遠端における収差図である。実施例３はズーム比３．５９、開口比４．１〜５．９程度のズームレンズである。 FIG. 7 is a lens cross-sectional view at the wide-angle end of the zoom lens according to Embodiment 3 of the present invention, and FIGS. 8 and 9 are aberration diagrams at the wide-angle end and telephoto end of the zoom lens according to Embodiment 3, respectively. The third exemplary embodiment is a zoom lens having a zoom ratio of 3.59 and an aperture ratio of about 4.1 to 5.9.
図１０は本発明の実施例４のズームレンズの広角端におけるレンズ断面図、図１１、図１２はそれぞれ実施例４のズームレンズの広角端、望遠端における収差図である。 FIG. 10 is a lens cross-sectional view at the wide-angle end of the zoom lens according to Embodiment 4 of the present invention. FIGS. 11 and 12 are aberration diagrams at the wide-angle end and telephoto end of the zoom lens according to Embodiment 4, respectively.
実施例４はズーム比３．８０、開口比４．１〜５．９程度のズームレンズである。 The fourth exemplary embodiment is a zoom lens having a zoom ratio of 3.80 and an aperture ratio of about 4.1 to 5.9.
図１３は本発明のズームレンズを備える撮像装置の要部概略図である。 FIG. 13 is a schematic diagram of a main part of an image pickup apparatus including the zoom lens according to the present invention.
各実施例のズームレンズはデジタルスチルカメラや銀塩フィルムカメラ等の撮像装置に用いられる撮影レンズ系である。レンズ断面図において、左方が被写体側（前方）で、右方が像側（後方）である。 The zoom lens of each embodiment is a photographing lens system used in an imaging apparatus such as a digital still camera or a silver salt film camera. In the lens cross-sectional view, the left side is the subject side (front), and the right side is the image side (rear).
レンズ断面図において、Ｌ１は正の屈折力（光学的パワー＝焦点距離の逆数）の第１レンズ群、Ｌ２は負の屈折力の第２レンズ群、Ｌ３は正の屈折力の第３レンズ群、Ｌ４は正の屈折力の第４レンズ群である。 In the lens cross-sectional view, L1 is a first lens group having a positive refractive power (optical power = reciprocal of focal length), L2 is a second lens group having a negative refractive power, and L3 is a third lens group having a positive refractive power. , L4 is a fourth lens unit having a positive refractive power.
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と共に移動する。 An aperture stop SP is located on the object side of the third lens unit L3 and moves together with the third lens unit L3 during zooming.
ＩＰは像面であり、ビデオカメラやデジタルスチル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（光電変換素子）の撮像面、銀塩フィルム用カメラのときはフィルム面等の感光面に相当する。 IP is an image plane. When used as a photographing optical system for a video camera or a digital still camera, an imaging plane of a solid-state imaging device (photoelectric conversion device) such as a CCD sensor or a CMOS sensor, or a camera for a silver salt film It corresponds to a photosensitive surface such as a film surface.
収差図において、ＦｎｏはＦナンバー、ｄ、ｇは各々ｄ線及びｇ線、Ｓ・Ｃは正弦条件である。ｄＭ、ｄＳはｄ線のメリディオナル像面、サジタル像面、ｇＭ、ｇＳはｇ線のメリディオナル像面、サジタル像面である。倍率色収差はｇ線によって表している。Ｙは像高である。 In the aberration diagrams, Fno is an F number, d and g are d-line and g-line, respectively, and S · C is a sine condition. dM and dS are the d-line meridional image plane and sagittal image plane, and gM and gS are the g-line meridional image plane and sagittal image plane. Lateral chromatic aberration is represented by the g-line. Y is the image height.
尚、以下の各実施例において広角端と望遠端のズーム位置は、変倍用レンズ群（第１、第３、第４レンズ群Ｌ１、Ｌ３，Ｌ４）が機構上、光軸上を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。 In each of the following embodiments, the zoom positions at the wide-angle end and the telephoto end can be moved on the optical axis by the zoom lens units (first, third, and fourth lens units L1, L3, and L4). The zoom position when positioned at both ends of this range.
各実施例では、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、各レンズ群Ｌ１〜Ｌ４が移動している。 In each embodiment, the lens units L1 to L4 are moved as indicated by arrows during zooming from the wide-angle end to the telephoto end.
具体的には、第１、第３、第４レンズ群Ｌ１、Ｌ３、Ｌ４が物体側へ単調移動している。 Specifically, the first, third, and fourth lens groups L1, L3, and L4 are monotonously moved toward the object side.
又、第２レンズ群Ｌ２は像側へ凸状の軌跡を描くように移動している。 The second lens unit L2 moves so as to draw a convex locus toward the image side.
このとき、広角端に比べて望遠端で第１レンズ群Ｌ１と第２レンズ群Ｌ２の間隔が大きく、第２レンズ群Ｌ２と第３レンズ群Ｌ３の間隔が小さく、第３レンズ群Ｌ３と第４レンズ群Ｌ４の間隔が小さくなるように各レンズ群が移動している。 At this time, the distance between the first lens unit L1 and the second lens unit L2 is larger at the telephoto end than at the wide angle end, the interval between the second lens unit L2 and the third lens unit L3 is small, and the third lens unit L3 and the third lens unit L3. Each lens group is moved so that the interval between the four lens groups L4 is reduced.
各実施例では、広角端において全体として略レトロフォーカスタイプの屈折力配置としている。 In each of the embodiments, a substantially retrofocus type refractive power arrangement is adopted as a whole at the wide-angle end.
又、望遠端では全体として略テレフォトタイプの屈折力配置としている。これにより高いズーム比を実現したズームレンズを得ている。 Further, the telephoto end has a substantially telephoto type refractive power arrangement as a whole. As a result, a zoom lens realizing a high zoom ratio is obtained.
また、全てのレンズ群を移動させてズーミング及び変倍に伴う像面変動の補正を行うことにより屈折力の効率的な分配を容易にしている。 In addition, efficient distribution of refractive power is facilitated by moving all the lens groups to correct image plane variation accompanying zooming and zooming.
更に、広角端にて光学全長が短くすることができ、例えば一眼レフ用の交換レンズとして最適な高ズーム比で小型なズームレンズを構成している。 Further, the optical total length can be shortened at the wide-angle end, and for example, a compact zoom lens is configured with a high zoom ratio that is optimal as an interchangeable lens for a single lens reflex camera.
尚、各実施例において、フォーカスは第２レンズ群Ｌ２を光軸に沿って移動させ行っている。 In each embodiment, focusing is performed by moving the second lens unit L2 along the optical axis.
各実施例において、各レンズ群は３枚（要素）以下のレンズより成っている。具体的には第１レンズ群Ｌ１は１枚の正レンズと１枚の負レンズより成っている。第２レンズ群Ｌ２は物体側から像側へ順に、像面側の面が凹形状の負レンズ、負レンズ、物体側の面が凸形状の正レンズより成っている。第３レンズ群Ｌ３は１枚の正レンズと１枚の負レンズより成っている。第４レンズ群Ｌ４は正レンズを１以上含む２枚又は３枚のレンズより成っている。 In each embodiment, each lens group includes three (elements) or less lenses. Specifically, the first lens unit L1 includes one positive lens and one negative lens. The second lens unit L2 includes, in order from the object side to the image side, a negative lens having a concave surface on the image surface side, a negative lens, and a positive lens having a convex surface on the object side. The third lens unit L3 is composed of one positive lens and one negative lens. The fourth lens unit L4 includes two or three lenses including one or more positive lenses.
以上のように各実施例では、全体として非常に少ないレンズ枚数で構成して光学系の小型化を図りつつ高い光学性能を得ている。 As described above, in each of the embodiments, a high optical performance is obtained while reducing the size of the optical system by configuring with a very small number of lenses as a whole.
各実施例において、正の屈折力の第１レンズ群Ｌ１は、最も有効径大きくなるレンズ群である。その第１レンズ群Ｌ１を２枚のレンズ構成とすることで、構成レンズ枚数を減らしてコンパクトな光学系を実現している。 In each embodiment, the first lens unit L1 having a positive refractive power is a lens unit having the largest effective diameter. Since the first lens unit L1 has a two-lens configuration, the number of constituent lenses is reduced and a compact optical system is realized.
またその２枚のレンズを正レンズと負レンズとすることで、色消しを良好に行っている。特に広角端から望遠端までの倍率色収差、望遠端での軸上色収差を良好に補正している。 Further, the two lenses are a positive lens and a negative lens, so that achromaticity is favorably performed. In particular, the lateral chromatic aberration from the wide-angle end to the telephoto end and the axial chromatic aberration at the telephoto end are corrected well.
負の屈折力の第２レンズ群Ｌ２は、大きな変倍分担を担っており、負の屈折力も強く第２レンズ群Ｌ２内部での収差発生も大きくなる。 The second lens unit L2 having a negative refractive power is responsible for a large variable magnification, and the negative refractive power is strong and the occurrence of aberrations in the second lens unit L2 is large.
第２レンズ群Ｌ２を前記のようなレンズ構成とすることで、強い負の屈折力を維持しながらも良好な収差補正を可能としている。特に簡素なレンズ構成でありながら高ズーム比でかつ高い光学性能を有したズームレンズを達成している。 By setting the second lens unit L2 to the lens configuration as described above, it is possible to correct aberrations while maintaining a strong negative refractive power. In particular, a zoom lens having a high zoom ratio and high optical performance has been achieved with a simple lens configuration.
正の屈折力の第３レンズ群Ｌ３は、軸上光線が全ズーム領域において比較的高い位置を通るレンズ群である。そのため、正レンズで発生する軸上収差を負レンズで補正する構成とし、少ないレンズ枚数で良好な光学性能を得ている。 The third lens unit L3 having a positive refractive power is a lens unit in which an axial ray passes through a relatively high position in the entire zoom region. For this reason, the axial aberration generated in the positive lens is corrected by the negative lens, and good optical performance is obtained with a small number of lenses.
正の屈折力の第４レンズ群Ｌ４には、比較的屈折力の弱いレンズを配置して１以上の面を非球面形状としている。これにより、第３レンズ群Ｌ３では補正しきれなかった軸上収差や、軸外の諸収差を効率的に補正している。 In the fourth lens unit L4 having a positive refractive power, a lens having a relatively weak refractive power is arranged so that one or more surfaces have an aspherical shape. As a result, axial aberrations that could not be corrected by the third lens unit L3 and various off-axis aberrations are efficiently corrected.
非球面レンズの材料は特に限定するものではないが、比較的容易に製造できることから、樹脂成形のものを採用することが望ましい。 The material of the aspherical lens is not particularly limited, but it is desirable to adopt a resin-molded one because it can be manufactured relatively easily.
もちろん、該材料はガラスでも構わず、ガラス基盤上に非球面形状の樹脂層を配置した所謂複合非球面レンズでも良い。 Of course, the material may be glass, or a so-called compound aspherical lens in which an aspherical resin layer is disposed on a glass substrate.
また各実施例のズームレンズを一眼レフカメラの交換レンズに適用する場合は、使用者の取扱いで傷が付かないように、比較的強度の弱い樹脂材料による非球面レンズは最も像側の面には配置しない方が望ましい。各実施例ではその点を考慮して樹脂製の非球面レンズを配置している。 In addition, when the zoom lens of each embodiment is applied to an interchangeable lens of a single-lens reflex camera, an aspheric lens made of a resin material having a relatively low strength is provided on the surface closest to the image side so as not to be damaged when handled by the user. Should not be placed. In each embodiment, a resin aspheric lens is arranged in consideration of this point.
また、第４レンズ群Ｌ４は比較的に有効径の小さいレンズ群である。 The fourth lens unit L4 is a lens unit having a relatively small effective diameter.
従ってそこに配置する非球面レンズも比較的小さい有効径のもので良く、非球面レンズの製造上の難易度も軽減される。そのような観点からも、レンズ有効径が大きくなる第１レンズ群Ｌ１、第２レンズ群Ｌ２には非球面レンズは配置せず、全て球面レンズより構成している。 Therefore, the aspherical lens disposed there may also have a relatively small effective diameter, and the difficulty in manufacturing the aspherical lens can be reduced. Also from such a viewpoint, the first lens unit L1 and the second lens unit L2 in which the effective lens diameter is large are not provided with aspherical lenses, and are all configured by spherical lenses.
以上のような構成とすることで各実施例のズームレンズは、高ズーム比でありながらコンパクトな光学系を達成している。さらに以下の条件式の１以上を満足するようにして各条件式に対応した効果を得ている。 With the configuration described above, the zoom lens of each embodiment achieves a compact optical system with a high zoom ratio. Furthermore, the effect corresponding to each conditional expression is obtained so as to satisfy one or more of the following conditional expressions.
ｉを物体側から像側への順番とするとき、該第ｉレンズ群の焦点距離をｆｉ、広角端における全系の焦点距離をｆｗ、広角端でのバックフォーカスをｂｆｗ（ここでバックフォーカスは、パワーのある最終レンズ面から像面までの距離である）、第４レンズ群Ｌ４の非球面形状の面を含むレンズの焦点距離をｆ４ａとするとき、
４．０ ＜ ｆ１／ｆｗ ＜ ７．０ ・・・（１）
２．０ ＜ ｆ３／ｆｗ ＜ ５．０ ・・・（２）
１．４ ＜ ｂｆｗ／ｆｗ ＜ ３．５ ・・・（３）
０．６ ＜ ｜ｆ２｜／ｆｗ ＜ ２．５ ・・・（４）
１．０ ＜ ｆ４／ｆｗ ＜ ３．０ ・・・（５）
０．８ ＜ ｜ｆ４ａ｜／ｆ４ ・・・（６）
なる条件を満足している。
When i is the order from the object side to the image side, the focal length of the i-th lens group is fi, the focal length of the entire system at the wide-angle end is fw, and the back focus at the wide-angle end is bfw (where the back focus is When the focal length of the lens including the aspherical surface of the fourth lens unit L4 is f4a,
4.0 <f1 / fw <7.0 (1)
2.0 <f3 / fw <5.0 (2)
1.4 <bfw / fw <3.5 (3)
0.6 <| f2 | / fw <2.5 (4)
1.0 <f4 / fw <3.0 (5)
0.8 <| f4a | / f4 (6)
Is satisfied.
条件式（１）は光学系全体の小型化と光学性能のバランスを取る為の条件である。条件式（１）の上限を超えて第１レンズ群Ｌ１の屈折力が弱くなると、所望の変倍をする為の第１レンズ群の移動量が大きくなる。又それと同時に望遠端で軸外光線を十分確保する為に有効径が大きくなり、光学系が大型化してくる。
また下限を超えて第１レンズ群Ｌ１の屈折力が強くなると、第１レンズ群Ｌ１内で発生する諸収差を少ないレンズ枚数で補正することが困難となる。
Conditional expression (1) is a condition for balancing the miniaturization of the entire optical system and the optical performance. When the upper limit of conditional expression (1) is exceeded and the refractive power of the first lens unit L1 becomes weak, the amount of movement of the first lens unit for performing desired zooming increases. At the same time, the effective diameter increases in order to sufficiently secure off-axis rays at the telephoto end, and the optical system becomes larger.
If the refractive power of the first lens unit L1 increases beyond the lower limit, it becomes difficult to correct various aberrations occurring in the first lens unit L1 with a small number of lenses.
また同じく下限を超えて第１レンズ群Ｌ１の屈折力が強くなると、広角端で第１、２レンズ群の合成で負の屈折力となっているレトロフォーカスタイプの屈折力配置の傾向が弱くなる。この結果十分な長さのバックフォーカスを確保することが難しくなる。 Similarly, when the refractive power of the first lens unit L1 increases beyond the lower limit, the tendency of the retrofocus type refractive power arrangement, which is a negative refractive power by combining the first and second lens units at the wide angle end, becomes weaker. . As a result, it becomes difficult to ensure a sufficiently long back focus.
各実施例のズームレンズは簡易で小型であることを目的としている。このため可能な限り少ないレンズ枚数で構成する必要があり、この為第１レンズ群Ｌ１が条件式（１）を満足することは重要となっている。 The zoom lens of each embodiment is intended to be simple and small. For this reason, it is necessary to configure the number of lenses as small as possible. For this reason, it is important that the first lens unit L1 satisfies the conditional expression (1).
特に、記録画面サイズが３５ｍｍフィルムより小さいフォーマット（例えば所謂ＡＰＳサイズ等）の一眼レフカメラの撮影レンズに適用した場合、クイックリターンミラー機構を入れる一定以上のバックフォーカスが必要となる。条件式（１）は一定以上のバックフォーカスを確保しつつも光学系の小型化を達成するために適した構成とする為の１つの条件である。 In particular, when it is applied to a photographing lens of a single-lens reflex camera having a recording screen size smaller than a 35 mm film (for example, a so-called APS size), a back focus of a certain level or more for inserting a quick return mirror mechanism is required. Conditional expression (1) is one condition for achieving a configuration suitable for achieving downsizing of the optical system while ensuring a certain back focus or more.
条件式（２）は、条件式（１）と同様に光学系全体の小型化と光学性能のバランスを取る為の条件である。条件式（２）の上限を超えて第３レンズ群Ｌ３の屈折力が弱くなると、所望の変倍をする為の第３レンズ群Ｌ３の移動量が大きくなり、光学系が大型化してくる。また下限を超えて第３レンズ群Ｌ３の屈折力が強くなると、第３レンズ群Ｌ３内で発生する諸収差を少ないレンズ枚数で補正することが困難となる。 Conditional expression (2) is a condition for balancing the miniaturization of the entire optical system and the optical performance as in conditional expression (1). When the upper limit of conditional expression (2) is exceeded and the refractive power of the third lens unit L3 becomes weak, the amount of movement of the third lens unit L3 for performing desired zooming increases, and the optical system increases in size. If the refractive power of the third lens unit L3 increases beyond the lower limit, it becomes difficult to correct various aberrations occurring in the third lens unit L3 with a small number of lenses.
条件式（３）は、コンパクトで高性能なズームレンズを実現しつつ広角端でのバックフォーカスｂｆｗを適切に設定する為のものである。 Conditional expression (3) is for appropriately setting the back focus bfw at the wide-angle end while realizing a compact and high-performance zoom lens.
条件式（３）の上限を超えて広角端でのバックフォーカスが長くなりすぎると、レンズ群が最も沈胴した状態の広角端でのレンズ全長が長くなり全系のコンパクトさが損なわれてくる。 When the upper limit of conditional expression (3) is exceeded and the back focus at the wide-angle end becomes too long, the total lens length at the wide-angle end when the lens group is most retracted becomes long and the compactness of the entire system is impaired.
また下限を超えてバックフォーカスが短くなりすぎると、クイックリターンミラー機構やオートフォーカス光学系などを配置するスペースが不十分となる。この結果、例えば一眼レフカメラに使用する光学系としては適さなくなる。 If the back focus is too short beyond the lower limit, the space for arranging the quick return mirror mechanism, the autofocus optical system, etc. will be insufficient. As a result, it is not suitable as an optical system used for, for example, a single-lens reflex camera.
条件式（４）の上限を超えて第２レンズ群Ｌ２の負の屈折力が弱くなると、所望の変倍をする為の第１レンズ群及び第３レンズ群との間の空気間隔変化量を大きくとる必要が生じる。この結果光学系が大型化するため良くない。逆に下限を超えて第２レンズ群Ｌ２の負の屈折力が強くなりすぎると、第３レンズ群Ｌ３に入射する軸上光線、軸外光線の高さが高くなり絞り径や第３レンズ群Ｌ３の有効径が大きくなって光学系が大型化するため良くない。 When the upper limit of conditional expression (4) is exceeded and the negative refractive power of the second lens unit L2 becomes weaker, the amount of change in the air gap between the first lens unit and the third lens unit for desired zooming is obtained. It is necessary to take a large size. As a result, the optical system becomes large, which is not good. On the other hand, if the negative refractive power of the second lens unit L2 exceeds the lower limit and becomes too strong, the height of the on-axis rays and off-axis rays incident on the third lens unit L3 increases, and the aperture diameter and the third lens unit are increased. Since the effective diameter of L3 becomes large and the optical system becomes large, it is not good.
また同時に、第２レンズ群Ｌ２内で発生する諸収差を少ないレンズ枚数で補正することが困難となる。 At the same time, it is difficult to correct various aberrations occurring in the second lens unit L2 with a small number of lenses.
条件式（５）の上限を超えて第４レンズ群Ｌ４の屈折力が弱くなると、所望の変倍をする為の第３レンズ群Ｌ３の移動量が大きくなり、光学系が大型化してくる。 When the upper limit of conditional expression (5) is exceeded and the refractive power of the fourth lens unit L4 becomes weaker, the amount of movement of the third lens unit L3 for desired zooming increases, and the optical system becomes larger.
また下限を超えて第４レンズ群Ｌ４の屈折力が強くなると、第４レンズ群Ｌ４から像面までの間に十分なバックフォーカスを確保するのが難しくなる。 If the refractive power of the fourth lens unit L4 increases beyond the lower limit, it becomes difficult to ensure a sufficient back focus between the fourth lens unit L4 and the image plane.
条件式（６）の範囲を外れて非球面レンズの屈折力が強くなりすぎると、ベース曲率の強いレンズ面に非球面形状を加工することになり、高い精度で非球面レンズを製造することが難しくなる。 If the refractive power of the aspherical lens becomes too strong outside the range of the conditional expression (6), the aspherical surface is processed into a lens surface with a strong base curvature, and the aspherical lens can be manufactured with high accuracy. It becomes difficult.
また、非球面レンズを樹脂材料で製造した場合、温度や湿度の環境変化による性能変化がより顕著に現れることになって望ましくない。
尚、更に好ましくは、前述の条件式（１）から（５）の数値範囲を以下の如く設定するのが良い。
In addition, when the aspherical lens is manufactured from a resin material, it is not desirable because a change in performance due to environmental changes in temperature and humidity appears more prominently.
More preferably, the numerical ranges of the conditional expressions (1) to (5) are set as follows.
４．２ ＜ ｆ１／ｆｗ ＜ ６．５ ・・・（１ａ）
２．２ ＜ ｆ３／ｆｗ ＜ ４．５ ・・・（２ａ）
１．６ ＜ ｂｆｗ／ｆｗ ＜ ３．０ ・・・（３ａ）
０．７ ＜ ｜ｆ２｜／ｆｗ ＜ ２．０ ・・・（４ａ）
１．２ ＜ ｆ４／ｆｗ ＜ ２．５ ・・・（５ａ）
１．０ ＜ ｜ｆ４ａ｜／ｆ４ ・・・（６ａ）
尚、条件式（６）の上限値は、２０とするのが良い。更に好ましくは１５とするのが良い。
4.2 <f1 / fw <6.5 (1a)
2.2 <f3 / fw <4.5 (2a)
1.6 <bfw / fw <3.0 (3a)
0.7 <| f2 | / fw <2.0 (4a)
1.2 <f4 / fw <2.5 (5a)
1.0 <| f4a | / f4 (6a)
The upper limit of conditional expression (6) is preferably 20. More preferably, 15 is preferable.
次に、本発明の数値実施例を示す。各数値実施例において、ｉは物体側から面の順序を示し、ｒｉはｉ番目のレンズ面（第ｉ面）の曲率半径、ｄｉは第ｉ面と第（ｉ＋１）面との間のレンズ肉厚および空気間隔、ｎｉ、νｉはそれぞれｄ線を基準とした屈折率、アッベ数を示す。 Next, numerical examples of the present invention will be shown. In each numerical example, i indicates the order of the surfaces from the object side, ri is the radius of curvature of the i-th lens surface (i-th surface), and di is the lens thickness between the i-th surface and the (i + 1) -th surface. Thickness, air spacing, ni, and νi indicate the refractive index and Abbe number with respect to the d-line, respectively.
非球面形状は光軸からの高さ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、
Ｘ＝（ｈ2 ／Ｒ）／［１＋｛１−(１＋ｋ)（ｈ／Ｒ）2｝１／２］
＋Ｂｈ4 ＋Ｃｈ6＋Ｄｈ8 ＋Ｅｈ10
で表される。
When the aspherical shape is x with the displacement in the optical axis direction at the position of the height h from the optical axis as x based on the surface vertex,
X = (h 2 / R) / [1+ {1− (1 + k) (h / R) 2 } 1/2 ]
+ Bh 4 + Ch 6 + Dh 8 + Eh 10
It is represented by
但し、ｋは円錐定数、Ｂ、Ｃ、Ｄ，Ｅは４次、６次、８次、１０次の非球面係数、Ｒは近軸曲率半径である。 Here, k is a conic constant, B, C, D, and E are fourth-order, sixth-order, eighth-order, and tenth-order aspherical coefficients, and R is a paraxial radius of curvature.
又、「ｅ−０Ｘ」は「×１０−ｘ」を意味している。ｆは焦点距離、ＦｎｏはＦナンバー、ωは半画角を示す。 “E-0X” means “× 10 −x ”. f represents a focal length, Fno represents an F number, and ω represents a half angle of view.
又、前述の各条件式と各数値実施例との関係を表１に示す。
数値実施例１
f= 18.6〜63.7 Fno= 4.1〜 5.9 2ω=72.4°〜24.2°
r 1= 65.351 d 1= 6.45 n 1=1.71300 v 1=53.9
r 2= -143.801 d 2= 1.80 n 2=1.84666 v 2=23.9
r 3= 1558.603 d 3= 可変
r 4= 104.107 d 4= 1.40 n 3=1.71300 v 3=53.9
r 5= 12.263 d 5= 6.01
r 6= -85.209 d 6= 1.20 n 4=1.71300 v 4=53.9
r 7= 25.821 d 7= 0.12
r 8= 19.088 d 8= 3.37 n 5=1.78472 v 5=25.7
r 9= 111.189 d 9= 可変
r10= 0.000(絞り) d10= 0.50
r11= 16.999 d11= 3.68 n 6=1.56384 v 6=60.7
r12= -31.931 d12= 4.43
r13= -14.390 d13= 1.91 n 7=1.75520 v 7=27.5
r14= -5243.554 d14= 可変
r15= -57.232 d15= 1.70 n 8=1.49171 v 8=57.4
r16= -34.466(非球面)d16= 0.15
r17= -137.704 d17= 5.47 n 9=1.48749 v 9=70.2
r18= -13.563 d18= 可変
焦点距離 18.61 34.34 63.67
可変間隔
d 3 3.27 15.66 31.96
d 9 24.46 10.76 2.55
d 14 2.92 1.61 0.97
非球面係数
（第16面）
K= 0.00 B= 8.369688e-05 C= 4.697525e-07 D=-4.006865e-09 E= 1.071226e-11
数値実施例２
f= 18.5〜 63.1 Fno= 1: 4.1〜 5.6 2ω=72.6°〜24.4°
r 1= 46.438 d 1= 2.00 n 1=1.84666 v 1=23.9
r 2= 32.642 d 2= 0.47
r 3= 34.288 d 3= 7.10 n 2=1.72916 v 2=54.7
r 4= 355.917 d 4= 可変
r 5= 129.932 d 5= 1.30 n 3=1.71300 v 3=53.9
r 6= 10.934 d 6= 5.22
r 7= -199.231 d 7= 1.10 n 4=1.71300 v 4=53.9
r 8= 21.077 d 8= 0.07
r 9= 15.611 d 9= 3.03 n 5=1.80518 v 5=25.4
r10= 48.600 d10= 可変
r11= 0.000(絞り) d11= 0.63
r12= 20.640 d12= 6.10 n 6=1.61405 v 6=55.0
r13= -14.914 d13= 0.65
r14= -12.909 d14= 1.46 n 7=1.66680 v 7=33.0
r15= -5636.339 d15= 可変
r16= 45.096 d16= 2.47 n 8=1.48749 v 8=70.2
r17= 1090.782 d17= 1.10
r18= -83.866(非球面)d18= 1.20 n 9=1.58306 v 9=30.2
r19= 130.625(非球面)d19= 0.85
r20= -74.594 d20= 3.96 n10=1.48749 v10=70.2
r21= -13.985 d21= 可変
r22= 0.000 d22= 可変
焦点距離 18.55 35.88 63.07
可変間隔
d 4 3.22 15.52 27.13
d 10 20.47 8.54 2.15
d 15 4.66 2.24 0.76
d 21 0.05 10.75 19.96
非球面係数
（第18面）
K= 0.00 B=-5.736678e-05 C=-1.820188e-07 D= 5.808664e-10 E= 4.254278e-13
（第19面）
K= 0.00 B= 1.118583e-05 C=-4.924430e-08 D= 6.670875e-12 E= 0.00
数値実施例３
f= 17.6〜 63.1 Fno= 1: 4.1〜 5.9 2ω=75.5°〜24.4°
r 1= 42.421 d 1= 2.00 n 1=1.84666 v 1=23.9
r 2= 29.070 d 2= 0.77
r 3= 30.114 d 3= 7.51 n 2=1.72916 v 2=54.7
r 4= 291.141 d 4= 可変
r 5= 105.618 d 5= 0.90 n 3=1.72916 v 3=54.7
r 6= 10.373 d 6= 5.21
r 7= -715.343 d 7= 0.90 n 4=1.71300 v 4=53.9
r 8= 20.142 d 8= 0.15
r 9= 14.419 d 9= 2.58 n 5=1.84666 v 5=23.9
r10= 30.284 d10= 可変
r11= 0.000(絞り) d11= 0.50
r12= 21.943 d12= 6.63 n 6=1.54814 v 6=45.8
r13= -12.586 d13= 0.59
r14= -11.486 d14= 1.00 n 7=1.64769 v 7=33.8
r15= -1095.172 d15= 可変
r16= 26.601 d16= 3.30 n 8=1.48749 v 8=70.2
r17= -102.779 d17= 2.13
r18= -98.782(非球面)d18= 1.00 n 9=1.58306 v 9=30.2
r19= 41.558 d19= 1.00
r20= 415.695 d20= 4.51 n10=1.48749 v10=70.2
r21= -15.491 d21= 可変
r22= 0.000 d22= 可変
焦点距離 17.60 36.86 63.13
可変間隔
d 4 2.52 14.86 25.09
d 10 18.52 7.45 2.83
d 15 5.88 2.57 0.60
d 21 0.46 13.13 21.98
非球面係数
(第18面)
K= 0.00 B=-5.743352e-05 C=-1.312106e-07 D= 9.587723e-10 E= 0.00
数値実施例４
f= 18.6〜 70.5 Fno= 1: 4.1〜 5.9 2ω=72.5°〜21.9°
r 1= 67.077 d 1= 6.50 n 1=1.69680 v 1=55.5
r 2= -161.945 d 2= 1.80 n 2=1.84666 v 2=23.9
r 3= 1132.825 d 3= 可変
r 4= 83.048 d 4= 1.40 n 3=1.72916 v 3=54.7
r 5= 12.446 d 5= 6.05
r 6= -84.027 d 6= 1.20 n 4=1.71300 v 4=53.9
r 7= 25.673 d 7= 0.12
r 8= 19.338 d 8= 3.33 n 5=1.78472 v 5=25.7
r 9= 111.618 d 9= 可変
r10= 0.000(絞り) d10= 0.50
r11= 16.677 d11= 3.95 n 6=1.56384 v 6=60.7
r12= -33.126 d12= 4.51
r13= -14.648 d13= 1.91 n 7=1.75520 v 7=27.5
r14= -557.228 d14= 可変
r15= -48.659 d15= 1.65 n 8=1.49171 v 8=57.4
r16= -37.214(非球面)d16= 0.15
r17= -197.038 d17= 5.34 n 9=1.48749 v 9=70.2
r18= -13.950 d18= 可変
焦点距離 18.58 45.27 70.51
可変間隔
d 3 3.26 23.11 38.11
d 9 25.60 7.32 2.56
d 14 3.21 1.39 1.00
非球面係数
（第16面）
K= 0.00 B= 8.207245e-05 C= 3.944734e-07 D=-2.633781e-09 E= 1.662769e-12
Table 1 shows the relationship between the above-described conditional expressions and numerical examples.
Numerical example 1
f = 18.6〜63.7 Fno = 4.1〜 5.9 2ω = 72.4 ° 〜24.2 °
r 1 = 65.351 d 1 = 6.45 n 1 = 1.71300 v 1 = 53.9
r 2 = -143.801 d 2 = 1.80 n 2 = 1.84666 v 2 = 23.9
r 3 = 1558.603 d 3 = variable
r 4 = 104.107 d 4 = 1.40 n 3 = 1.71300 v 3 = 53.9
r 5 = 12.263 d 5 = 6.01
r 6 = -85.209 d 6 = 1.20 n 4 = 1.71300 v 4 = 53.9
r 7 = 25.821 d 7 = 0.12
r 8 = 19.088 d 8 = 3.37 n 5 = 1.78472 v 5 = 25.7
r 9 = 111.189 d 9 = variable
r10 = 0.000 (aperture) d10 = 0.50
r11 = 16.999 d11 = 3.68 n 6 = 1.56384 v 6 = 60.7
r12 = -31.931 d12 = 4.43
r13 = -14.390 d13 = 1.91 n 7 = 1.75520 v 7 = 27.5
r14 = -5243.554 d14 = variable
r15 = -57.232 d15 = 1.70 n 8 = 1.49171 v 8 = 57.4
r16 = -34.466 (aspherical surface) d16 = 0.15
r17 = -137.704 d17 = 5.47 n 9 = 1.48749 v 9 = 70.2
r18 = -13.563 d18 = variable
Focal length 18.61 34.34 63.67
Variable interval
d 3 3.27 15.66 31.96
d 9 24.46 10.76 2.55
d 14 2.92 1.61 0.97
Aspheric coefficient (16th surface)
K = 0.00 B = 8.369688e-05 C = 4.697525e-07 D = -4.006865e-09 E = 1.071226e-11
Numerical example 2
f = 18.5 to 63.1 Fno = 1: 4.1 to 5.6 2ω = 72.6 ° to 24.4 °
r 1 = 46.438 d 1 = 2.00 n 1 = 1.84666 v 1 = 23.9
r 2 = 32.642 d 2 = 0.47
r 3 = 34.288 d 3 = 7.10 n 2 = 1.72916 v 2 = 54.7
r 4 = 355.917 d 4 = variable
r 5 = 129.932 d 5 = 1.30 n 3 = 1.71300 v 3 = 53.9
r 6 = 10.934 d 6 = 5.22
r 7 = -199.231 d 7 = 1.10 n 4 = 1.71300 v 4 = 53.9
r 8 = 21.077 d 8 = 0.07
r 9 = 15.611 d 9 = 3.03 n 5 = 1.80518 v 5 = 25.4
r10 = 48.600 d10 = variable
r11 = 0.000 (aperture) d11 = 0.63
r12 = 20.640 d12 = 6.10 n 6 = 1.61405 v 6 = 55.0
r13 = -14.914 d13 = 0.65
r14 = -12.909 d14 = 1.46 n 7 = 1.66680 v 7 = 33.0
r15 = -5636.339 d15 = variable
r16 = 45.096 d16 = 2.47 n 8 = 1.48749 v 8 = 70.2
r17 = 1090.782 d17 = 1.10
r18 = -83.866 (aspherical surface) d18 = 1.20 n 9 = 1.58306 v 9 = 30.2
r19 = 130.625 (aspherical surface) d19 = 0.85
r20 = -74.594 d20 = 3.96 n10 = 1.48749 v10 = 70.2
r21 = -13.985 d21 = variable
r22 = 0.000 d22 = Variable
Focal length 18.55 35.88 63.07
Variable interval
d 4 3.22 15.52 27.13
d 10 20.47 8.54 2.15
d 15 4.66 2.24 0.76
d 21 0.05 10.75 19.96
Aspheric coefficient (18th surface)
K = 0.00 B = -5.736678e-05 C = -1.820188e-07 D = 5.808664e-10 E = 4.254278e-13
(19th page)
K = 0.00 B = 1.118583e-05 C = -4.924430e-08 D = 6.670875e-12 E = 0.00
Numerical Example 3
f = 17.6 to 63.1 Fno = 1: 4.1 to 5.9 2ω = 75.5 ° to 24.4 °
r 1 = 42.421 d 1 = 2.00 n 1 = 1.84666 v 1 = 23.9
r 2 = 29.070 d 2 = 0.77
r 3 = 30.114 d 3 = 7.51 n 2 = 1.72916 v 2 = 54.7
r 4 = 291.141 d 4 = variable
r 5 = 105.618 d 5 = 0.90 n 3 = 1.72916 v 3 = 54.7
r 6 = 10.373 d 6 = 5.21
r 7 = -715.343 d 7 = 0.90 n 4 = 1.71300 v 4 = 53.9
r 8 = 20.142 d 8 = 0.15
r 9 = 14.419 d 9 = 2.58 n 5 = 1.84666 v 5 = 23.9
r10 = 30.284 d10 = variable
r11 = 0.000 (aperture) d11 = 0.50
r12 = 21.943 d12 = 6.63 n 6 = 1.54814 v 6 = 45.8
r13 = -12.586 d13 = 0.59
r14 = -11.486 d14 = 1.00 n 7 = 1.64769 v 7 = 33.8
r15 = -1095.172 d15 = variable
r16 = 26.601 d16 = 3.30 n 8 = 1.48749 v 8 = 70.2
r17 = -102.779 d17 = 2.13
r18 = -98.782 (aspherical surface) d18 = 1.00 n 9 = 1.58306 v 9 = 30.2
r19 = 41.558 d19 = 1.00
r20 = 415.695 d20 = 4.51 n10 = 1.48749 v10 = 70.2
r21 = -15.491 d21 = variable
r22 = 0.000 d22 = Variable
Focal length 17.60 36.86 63.13
Variable interval
d 4 2.52 14.86 25.09
d 10 18.52 7.45 2.83
d 15 5.88 2.57 0.60
d 21 0.46 13.13 21.98
Aspheric coefficient
(18th page)
K = 0.00 B = -5.743352e-05 C = -1.312106e-07 D = 9.587723e-10 E = 0.00
Numerical Example 4
f = 18.6〜70.5 Fno = 1: 4.1〜 5.9 2ω = 72.5 ° 〜21.9 °
r 1 = 67.077 d 1 = 6.50 n 1 = 1.69680 v 1 = 55.5
r 2 = -161.945 d 2 = 1.80 n 2 = 1.84666 v 2 = 23.9
r 3 = 1132.825 d 3 = variable
r 4 = 83.048 d 4 = 1.40 n 3 = 1.72916 v 3 = 54.7
r 5 = 12.446 d 5 = 6.05
r 6 = -84.027 d 6 = 1.20 n 4 = 1.71300 v 4 = 53.9
r 7 = 25.673 d 7 = 0.12
r 8 = 19.338 d 8 = 3.33 n 5 = 1.78472 v 5 = 25.7
r 9 = 111.618 d 9 = variable
r10 = 0.000 (aperture) d10 = 0.50
r11 = 16.677 d11 = 3.95 n 6 = 1.56384 v 6 = 60.7
r12 = -33.126 d12 = 4.51
r13 = -14.648 d13 = 1.91 n 7 = 1.75520 v 7 = 27.5
r14 = -557.228 d14 = variable
r15 = -48.659 d15 = 1.65 n 8 = 1.49171 v 8 = 57.4
r16 = -37.214 (Aspherical surface) d16 = 0.15
r17 = -197.038 d17 = 5.34 n 9 = 1.48749 v 9 = 70.2
r18 = -13.950 d18 = variable
Focal length 18.58 45.27 70.51
Variable interval
d 3 3.26 23.11 38.11
d 9 25.60 7.32 2.56
d 14 3.21 1.39 1.00
Aspheric coefficient (16th surface)
K = 0.00 B = 8.207245e-05 C = 3.944734e-07 D = -2.633781e-09 E = 1.662769e-12
次に、本発明のズームレンズを用いた一眼レフカメラシステムの実施形態を、図１３を用いて説明する。 Next, an embodiment of a single-lens reflex camera system using the zoom lens of the present invention will be described with reference to FIG.
図１３において、１０は一眼レフカメラ本体、１１は本発明によるズームレンズを搭載した交換レンズ、１２は交換レンズ１１を通して得られる被写体像を記録するフィルムや撮像素子などの記録手段、１３は交換レンズ１１からの被写体像を観察するファインダー光学系、１４は交換レンズ１１からの被写体像を記録手段１２とファインダー光学系１３に切り替えて伝送するための回動するクイックリターンミラーである。ファインダーで被写体像を観察する場合は、クイックリターンミラー１４を介してピント板１５に結像した被写体像をペンタプリズム１６で正立像としたのち、接眼光学系１７で拡大して観察する。撮影時にはクイックリターンミラー１４が矢印方向に回動して被写体像は記録手段１２に結像して記録される。１８はサブミラー、１９は焦点検出装置である。 In FIG. 13, 10 is a single-lens reflex camera body, 11 is an interchangeable lens equipped with a zoom lens according to the present invention, 12 is a recording means such as a film or an image sensor for recording a subject image obtained through the interchangeable lens 11, and 13 is an interchangeable lens. A finder optical system for observing the subject image from 11, and a rotating quick return mirror 14 for switching and transmitting the subject image from the interchangeable lens 11 to the recording means 12 and the finder optical system 13. When the subject image is observed with the viewfinder, the subject image formed on the focusing plate 15 via the quick return mirror 14 is converted into an erect image with the pentaprism 16 and then magnified with the eyepiece optical system 17 for observation. At the time of shooting, the quick return mirror 14 rotates in the direction of the arrow, and the subject image is formed on the recording means 12 and recorded. Reference numeral 18 denotes a submirror, and 19 denotes a focus detection device.
このように本発明のズームレンズを一眼レフカメラ交換レンズ等の光学機器に適用することにより、高い光学性能を有した光学機器が実現できる。 Thus, by applying the zoom lens of the present invention to an optical device such as a single lens reflex camera interchangeable lens, an optical device having high optical performance can be realized.
尚、本発明はクイックリターンミラーのない一眼レフカメラにも同様に適用することができる。 It should be noted that the present invention can be similarly applied to a single-lens reflex camera without a quick return mirror.
Ｌ１ 第１レンズ群
Ｌ２ 第２レンズ群
Ｌ３ 第３レンズ群
Ｌ４ 第４レンズ群
ＳＰ 絞り
ＩＰ 像面
ｄ ｄ線
ｇ ｇ線
Ｓ・Ｃ 正弦条件
ｄＭ ｄ線のメリディオナル像面
ｄＳ ｄ線のサジタル像面
ｇＭ ｇ線のメリディオナル像面
ｇＳ ｇ線のサジタル像面
L1 1st lens group L2 2nd lens group L3 3rd lens group L4 4th lens group SP Aperture IP image surface d d line g g line S / C sine condition dM d line meridional image surface dS sagittal image surface of d line gM g-line meridional image plane gS g-line sagittal image plane
Claims (12)
ｉを物体側から像側への順番とするとき、該第ｉレンズ群の焦点距離をｆｉ、広角端における全系の焦点距離をｆｗとするとき、
４．０ ＜ ｆ１／ｆｗ ＜ ７．０
２．０ ＜ ｆ３／ｆｗ ＜ ５．０
なる条件を満足することを特徴とするズームレンズ。 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, a third lens group having a positive refractive power, and a fourth lens group having a positive refractive power are provided. At least the first lens group and the second lens group at the telephoto end compared to the wide-angle end, and at least the second lens group and the third lens group so that the distance between the second lens group and the third lens group is small. In the zoom lens in which the first, third, and fourth lens groups move monotonously on the optical axis toward the object side,
When i is the order from the object side to the image side, the focal length of the i-th lens group is fi, and the focal length of the entire system at the wide angle end is fw.
4.0 <f1 / fw <7.0
2.0 <f3 / fw <5.0
A zoom lens characterized by satisfying the following conditions:
１．４ ＜ ｂｆｗ／ｆｗ ＜ ３．５
なる条件を満足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 back focus at the wide-angle end is bfw,
1.4 <bfw / fw <3.5
The zoom lens according to claim 1, wherein the following condition is satisfied.
０．６ ＜ ｜ｆ２｜／ｆｗ ＜ ２．５
１．０ ＜ ｆ４／ｆｗ ＜ ３．０
なる条件を満足することを特徴とする請求項１から５のいずれか１項に記載のズームレンズ。 The focal lengths f2 and f4 of the second and fourth lens groups are
0.6 <| f2 | / fw <2.5
1.0 <f4 / fw <3.0
The zoom lens according to claim 1, wherein the following condition is satisfied.
０．８ ＜ ｜ｆ４ａ｜／ｆ４
なる条件を満足することを特徴とする請求項１から７のいずれか１項に記載のズームレンズ。 The fourth lens group includes a lens including an aspherical surface and a lens including only a spherical surface, and when the focal length of the lens including the aspherical surface is f4a,
0.8 <| f4a | / f4
The zoom lens according to claim 1, wherein the following condition is satisfied.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2010014844A (en) * | 2008-07-02 | 2010-01-21 | Sony Corp | Zoom lens and pickup apparatus |
| US7889438B2 (en) | 2009-05-12 | 2011-02-15 | Tamron Co., Ltd. | Large-aperture zoom lens |
| CN114578534A (en) * | 2020-12-02 | 2022-06-03 | 大立光电股份有限公司 | Image lens assembly, zooming image capturing device and electronic device |
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|---|---|---|---|---|
| JP2000347102A (en) * | 1999-06-04 | 2000-12-15 | Konica Corp | Zoom lens |
| JP2002098895A (en) * | 2000-09-25 | 2002-04-05 | Olympus Optical Co Ltd | Zoom lens having image blur correcting function |
| JP2003177317A (en) * | 2001-12-12 | 2003-06-27 | Nikon Corp | Zoom lens |
| JP2005181556A (en) * | 2003-12-18 | 2005-07-07 | Sigma Corp | Large diameter zoom lens |
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2005
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Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2000347102A (en) * | 1999-06-04 | 2000-12-15 | Konica Corp | Zoom lens |
| JP2002098895A (en) * | 2000-09-25 | 2002-04-05 | Olympus Optical Co Ltd | Zoom lens having image blur correcting function |
| JP2003177317A (en) * | 2001-12-12 | 2003-06-27 | Nikon Corp | Zoom lens |
| JP2005181556A (en) * | 2003-12-18 | 2005-07-07 | Sigma Corp | Large diameter zoom lens |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2010014844A (en) * | 2008-07-02 | 2010-01-21 | Sony Corp | Zoom lens and pickup apparatus |
| JP4656453B2 (en) * | 2008-07-02 | 2011-03-23 | ソニー株式会社 | Zoom lens and imaging device |
| US7889438B2 (en) | 2009-05-12 | 2011-02-15 | Tamron Co., Ltd. | Large-aperture zoom lens |
| CN102253475A (en) * | 2009-05-12 | 2011-11-23 | 株式会社腾龙 | Large-aperture zoom lens |
| CN101887162B (en) * | 2009-05-12 | 2012-05-09 | 株式会社腾龙 | Large-aperture zoom lens |
| CN114578534A (en) * | 2020-12-02 | 2022-06-03 | 大立光电股份有限公司 | Image lens assembly, zooming image capturing device and electronic device |
| CN114578534B (en) * | 2020-12-02 | 2023-11-07 | 大立光电股份有限公司 | Image lens group, zooming and image capturing device and electronic device |
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|---|---|
| JP4871558B2 (en) | 2012-02-08 |
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