JP3723654B2 - Shooting lens system - Google Patents
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- JP3723654B2 JP3723654B2 JP01664997A JP1664997A JP3723654B2 JP 3723654 B2 JP3723654 B2 JP 3723654B2 JP 01664997 A JP01664997 A JP 01664997A JP 1664997 A JP1664997 A JP 1664997A JP 3723654 B2 JP3723654 B2 JP 3723654B2
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Description
【０００１】
【技術分野】
本発明は、主に電子スチルカメラ等に用いられる撮影レンズ系に関するものである。
【０００２】
【従来技術及びその問題点】
近年、従来の銀塩フィルムを使用するカメラと比較して、容易に撮影、鑑賞が可能な電子スチルカメラが普及しつつある。また一般家庭に普及が進んできたパーソナルコンピュータ等で簡単に静止画像を入力する装置としても小型で高解像の電子スチルカメラが望まれている。
【０００３】
このような目的で利用される電子スチルカメラは、高い性能だけでなく、小型化と低コスト化の要求が非常に高い。さらに、電子スチルカメラなどのように小型の撮像素子を用いるカメラでは、素子の小型化に伴い１画素の大きさが小さくなり、非常に高解像度の撮影光学系が必要とされる。さらに、レンズ系と撮像素子との間に、フィルター等を配置するスペースが必要なため、十分長いバックフォーカスも要求される。
また、カラー撮像素子を用いる光学系は、色ムラ防止のために撮像素子にレンズから射出した光が垂直に入射する、いわゆるテレセントリック性が良好であることが要求される。
【０００４】
この種の撮影レンズ系で５枚構成の光学系としては、特開平２−８５８１６号公報や特開平３−６３６１３号公報などが知られているが、前者は大口径であるが半画角２０°以下で画角が狭く、後者は半画角２７°前後まで広角化されているが歪曲収差が大きく改善の余地がある。
また、これらの光学系は、動画を対象としている場合が多く、電子スチルカメラ等で利用するには、解像度が低く改善の余地がある。
【０００５】
【発明の目的】
本発明は、十分なバックフォーカスと高解像度に対応可能な光学性能を有し、テレセントリック性が良好で、コンパクトで構成枚数の少ない広角の撮影レンズ系を提供することを目的とする。
【０００６】
【発明の概要】
本発明の撮影レンズ系は、物体側から順に、負の屈折力を有する第１レンズからなる第１レンズ群と；正の屈折力を有する第２レンズと、負の屈折力を有する第３レンズと、正の屈折力を有する第４レンズの３群３枚のレンズからなる第２レンズ群と；正の第５レンズからなる第３レンズ群と；からなる全体として５枚構成のレンズ系であって、第２レンズ群の第２レンズは、物体側に凸面を有する正レンズからなり、第４レンズは、像側に凸面を有する正レンズからなり、下記の条件式（１）ないし（５）を満足することを特徴としている。
（１）１．２＜Ｆ2 ／Ｆ≦１．９０３
（２）１．１＜｜Ｆ1 ／Ｆ2 ｜＜１．７
（３）０．８＜Ｆ3 ／Ｆ2 ≦１．２８４
（４）２．５＜｜（ｆ 2 ＋ｆ 4 ）／ｆ 3 ｜＜３．７
（５）１．３０２≦｜ｒ 3 ／ｒ 8 ｜≦１．５６８
但し、
Ｆ：レンズ全系の焦点距離、
Ｆ1 ：第１レンズ群の焦点距離、
Ｆ2 ：第２レンズ群の焦点距離、
Ｆ3 ：第３レンズ群の焦点距離。
ｆ i ：物体側から第ｉ番目のレンズの焦点距離、
ｒ i ：物体側から第ｉ番目の面の曲率半径、
である。
【０００８】
また、本発明の撮影レンズ系において、より具体的には、第１レンズ群を構成する第１レンズを像側に凹面を有するメニスカスレンズから構成し、第３レンズ群を構成する第５レンズを物体側に凸面を有する正レンズから構成し、さらに下記条件式（６）及び（又は）（７）を満足させることが望ましい。
（６）０．２５＜｜ｄ2 ／Ｆ1 ｜＜０．５
（７）０．５＜ｒ9 ／Ｆ3 ＜１．０
但し、ｄ2 ：第１レンズと第２レンズの空気間隔、
である。
【０００９】
【発明の実施の形態】
本発明の撮影レンズ系は、十分なバックフォーカスを確保するとともに、広角化を図るため、最も物体側に負の屈折力（パワー）を有する第１レンズ群を配置し、続いて３群３枚構成からなる第２レンズ群を配置し、さらに良好なテレセントリック性を得るため、最も像側には正の屈折力（パワー）を有する第３レンズ群を配置する。
このとき、第２レンズ群の屈折力と、第２レンズ群に対する、第１レンズ群及び第３レンズ群の屈折力を適切に配分することにより、良好な性能と十分長いバックフォーカスとテレセントリック性が得られる。また構成レンズ枚数を少なくするため、第１レンズ群と第３レンズ群は、それぞれ単レンズから構成している。
【００１０】
条件式（１）は、第２レンズ群の焦点距離とレンズ全系の焦点距離の比に関する条件である。
条件式（１）の下限を越えて、レンズ全系の屈折力に対する第２レンズ群の屈折力が強くなると、第２レンズ群内の各レンズの屈折力が増大し、球面収差、コマ収差を小さく抑えることが困難となり、画面全体のコントラストの低下を伴う。
条件式（１）の上限を越えて、第２レンズ群の屈折力が弱くなると、像面湾曲が補正不足となるとともに、非点隔差が大きくなる。
【００１１】
条件式（２）は、第１レンズ群の焦点距離と第２レンズ群の焦点距離の比に関するものである。
条件式（２）の下限を越えると、第２レンズ群に対する第１レンズ群の負の屈折力が強くなり、強い負の歪曲収差が発生するとともに、球面収差及びコマフレアーを良好に補正することが困難となる
条件式（２）の上限を越えると、第１レンズ群の負の屈折力が弱くなり、十分なバックフォーカスを確保することが困難になるとともに、像面湾曲が補正不足となり広角化も難しくなる。
【００１２】
条件式（３）は、第３レンズ群の焦点距離と第２レンズ群の焦点距離の比に関するものである。
条件式（３）の下限を越えると、第２レンズ群に対する第３レンズ群の屈折力が強くなりすぎ、テレセントリック性は良好になるが、負の歪曲収差が大きくなるとともに、像面湾曲、非点収差を良好に補正することも困難になる。またペッツバール和が増大し、良好な像面性能を得ることが困難になるとともに、バックフォーカスを長くすることが困難になる。
条件式（３）の上限を越えると、第３レンズ群の正の屈折力が弱くなり、それとともにテレセントリック性を維持するために、第２レンズ群の像側の正レンズの屈折力が増大し、特に周辺部におけるコマフレアーの発生を小さくすることが困難になる。
【００１３】
条件式（４）は、第２レンズ群を構成する正レンズと負レンズの屈折力配分に関する条件である。
条件式（４）の下限を越えると、第２レンズ群内の正レンズの屈折力が強くなりすぎ、逆に負レンズの屈折力の減少によりペッツバール和が大きくなり、像面湾曲を良好に補正することが困難になる。
条件式（４）の上限を越えると、第２レンズ群内の負レンズの屈折力が増大し、球面収差、コマ収差を小さく抑えることが困難になる。
【００１４】
条件式（５）は、第２レンズ群の最も物体側の面（第２レンズの物体側の面）の曲率半径と最も像側の面（第４レンズの像側の面）の曲率半径の比に関する条件である。
条件式（５）の下限を越えると、最も物体側の面の曲率半径が小さくなり、特にコマ収差が悪化して、コントラスト低下の原因となる。
条件式（５）の上限を越えると、最も像側の面の曲率半径が小さくなり、特に像面湾曲、非点収差を良好に補正することが困難になる。
【００１５】
条件式（６）は、第１レンズ群と第２レンズ群の空気間隔（第１レンズと第２レンズ）の空気間隔と、第１レンズ群の焦点距離の比に関する条件である。
条件式（６）の下限を越えると、十分長いバックフォーカスを確保することが困難となる。
条件式（６）の上限を越えると、バックフォーカスは十分確保することができるが、諸収差の補正、特に球面収差、コマ収差の補正が困難になる。
【００１６】
条件式（７）は、第３レンズ群（正の第５レンズ）の物体側の面の曲率半径と第３レンズ群（第５レンズ）の焦点距離に関する条件である。
条件式（７）の範囲内で、正の第５レンズの物体側の曲率半径を決めることにより、諸収差を悪化させることなく、良好なテレセントリック性を確保することが可能になる。
【００１７】
以下、具体的な数値実施例について、本発明を説明する。以下の実施例１ないし５は、各レンズ構成図に示すように、いずれも、物体側から順に、像側に強い凹面を有するメニスカス負レンズ１ｎからなる第１レンズ群１０、物体側に強い凸面を有する正レンズ２ｐ、両凹面の負レンズ３ｎ及び像側に強い凸面を有する正レンズ４ｐから構成される第２レンズ群２０、物体側に強い凸面を有する正レンズ５ｐからなる第３レンズ群３０、及び撮像素子のカバーガラスである平行平面ガラスＧを基本構成としている。絞りＳは、第２レンズ群２０中の第２レンズ２ｐと第３レンズ３ｎの間に配置されている。平行平面ガラスＧは、例えば、水晶フィルタ、赤外線カットフィルタ、カバーガラスからなり、その像側の面が撮像面である。
【００１８】
諸収差図中、ｄ線、ｇ線、Ｃ線は、球面収差、色収差、倍率色収差の波長を示す。非点収差図におけるＳはサジタル像面、Ｍはメリディオナル像面を示している。表および図面中、FNO はＦナンバー、F はレンズ全系の焦点距離、W は半画角、fBはバックフォーカスを表す。Ｒは曲率半径、Ｄはレンズ厚またはレンズ間隔、Ｎd はｄ線の屈折率、νd はアッベ数を示す。バックフォーカスfBは、第３レンズ群の最終面（ｒ１０面）から平行平面ガラスＧの像側面（ｒ１２）迄の空気換算距離（fB=d10+(d11/N11)）である。
【００１９】
［実施例１］
図１は本発明の撮影レンズ系の第１の実施例のレンズ構成図、図２はその諸収差図、表１はその数値データである。
【００２０】
【表１】
［実施例２］
図３は本発明の撮影レンズ系の第２の実施例のレンズ構成図、図４はその諸収差図、表２はその数値データである。
【００２２】
【表２】
［実施例３］
図５は本発明の撮影レンズ系の第３の実施例のレンズ構成図、図６はその諸収差図、表３はその数値データである。
【００２４】
【表３】
［実施例４］
図７は本発明の撮影レンズ系の第４の実施例のレンズ構成図、図８はその諸収差図、表４はその数値データである。
【００２６】
【表４】
［実施例５］
図９は本発明の撮影レンズ系の第５の実施例のレンズ構成図、図１０はその諸収差図、表５はその数値データである。
【００２８】
【表５】
次に、実施例１ないし５の各条件式に対する値を表６に示す。
【表６】
表６から明らかなように、実施例１ないし５の数値は、条件式（１）ないし（７）を満足している。また、収差図から明らかなように、各収差も良好に補正され、特に特開平３−６３６１３号公報記載の撮影レンズに比べ歪曲収差が小さい。
【００３１】
【発明の効果】
本発明によれば、十分なバックフォーカスと高解像度に対応可能な光学性能を有し、テレセントリック性が良好で、コンパクトで構成枚数の少ない広角の撮影レンズ系を得ることができる。
【図面の簡単な説明】
【図１】本発明による撮影レンズ系の第１の実施例のレンズ構成図である。
【図２】図１の撮影レンズ系の諸収差図である。
【図３】本発明による撮影レンズ系の第２の実施例のレンズ構成図である。
【図４】図３の撮影レンズ系の諸収差図である。
【図５】本発明による撮影レンズ系の第３の実施例のレンズ構成図である。
【図６】図５の撮影レンズ系の諸収差図である。
【図７】本発明による撮影レンズ系の第４の実施例のレンズ構成図である。
【図８】図７の撮影レンズ系の諸収差図である。
【図９】本発明による撮影レンズ系の第５の実施例のレンズ構成図である。
【図１０】図９の撮影レンズ系の諸収差図である。
【符号の説明】
１０ 第１レンズ群
２０ 第２レンズ群
３０ 第３レンズ群
Ｓ 絞り
Ｇ 平行平面ガラス[0001]
【Technical field】
The present invention relates to a photographing lens system mainly used for an electronic still camera or the like.
[0002]
[Prior art and its problems]
In recent years, electronic still cameras that can be easily photographed and viewed as compared with conventional cameras using a silver salt film are becoming popular. In addition, a small and high-resolution electronic still camera is desired as a device for easily inputting a still image on a personal computer or the like that has been widely used in general households.
[0003]
An electronic still camera used for such a purpose not only has high performance, but also demands for miniaturization and cost reduction are very high. Furthermore, in a camera using a small image sensor such as an electronic still camera, the size of one pixel is reduced with the miniaturization of the element, and a very high resolution photographing optical system is required. Furthermore, since a space for arranging a filter or the like is required between the lens system and the image sensor, a sufficiently long back focus is also required.
In addition, an optical system using a color image sensor is required to have good so-called telecentricity in which light emitted from a lens enters the image sensor vertically to prevent color unevenness.
[0004]
Japanese Laid-Open Patent Publication No. 2-85816 and Japanese Laid-Open Patent Publication No. 3-63613 are known as an optical system of this type with a photographic lens system having five lenses. The former has a large aperture but a half angle of view of 20 The angle of view is narrow at less than 0 °, and the latter is widened to a half angle of view around 27 °, but the distortion is large and there is room for improvement.
In addition, these optical systems are often intended for moving images, and there is room for improvement because the resolution is low for use in electronic still cameras and the like.
[0005]
OBJECT OF THE INVENTION
It is an object of the present invention to provide a wide-angle photographic lens system that has sufficient back focus and high optical performance to cope with high resolution, has good telecentricity, is compact, and has a small number of components.
[0006]
SUMMARY OF THE INVENTION
The photographing lens system of the present invention includes, in order from the object side, a first lens group including a first lens having a negative refractive power; a second lens having a positive refractive power; and a third lens having a negative refractive power. And a second lens group consisting of three lenses in three groups of the fourth lens having a positive refractive power; and a third lens group consisting of a positive fifth lens; The second lens of the second lens group is a positive lens having a convex surface on the object side, and the fourth lens is a positive lens having a convex surface on the image side, and the following conditional expressions (1) to (5 ) ) .
(1) 1.2 <F 2 / F ≦ 1.903
(2) 1.1 <| F 1 / F 2 | <1.7
(3) 0.8 <F 3 / F 2 ≦ 1.284
(4) 2.5 <| (f 2 + F 4 ) / F 3 | <3.7
(5) 1.302 ≦ | r 3 / R 8 | ≦ 1.568
However,
F: focal length of the entire lens system
F 1 : focal length of the first lens group,
F 2 : focal length of the second lens group,
F 3 : focal length of the third lens group.
f i : Focal length of the i-th lens from the object side,
r i : Radius of curvature of the i-th surface from the object side,
It is.
[0008]
In the photographic lens system of the present invention, more specifically, the first lens constituting the first lens group is constituted by a meniscus lens having a concave surface on the image side, and the fifth lens constituting the third lens group is provided. It is desirable that the lens is composed of a positive lens having a convex surface on the object side, and further satisfies the following conditional expressions (6) and / or (7).
(6) 0.25 <| d 2 / F 1 | <0.5
(7) 0.5 <r 9 / F 3 <1.0
Where d 2 is the air distance between the first lens and the second lens,
It is.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
In the photographic lens system of the present invention, in order to secure a sufficient back focus and to widen the angle, the first lens group having a negative refractive power (power) is disposed closest to the object side, and then three lenses in three groups. The second lens group having the configuration is arranged, and in order to obtain better telecentricity, the third lens group having a positive refractive power (power) is arranged on the most image side.
At this time, by appropriately distributing the refractive power of the second lens group and the refractive power of the first lens group and the third lens group to the second lens group, good performance, sufficiently long back focus and telecentricity can be obtained. can get. In order to reduce the number of constituent lenses, each of the first lens group and the third lens group is composed of a single lens.
[0010]
Conditional expression (1) is a condition regarding the ratio of the focal length of the second lens group to the focal length of the entire lens system.
When the refractive power of the second lens unit becomes strong relative to the refractive power of the entire lens system beyond the lower limit of conditional expression (1), the refractive power of each lens in the second lens unit increases, and spherical aberration and coma aberration are reduced. It becomes difficult to keep it small, which is accompanied by a decrease in contrast of the entire screen.
If the upper limit of conditional expression (1) is exceeded and the refractive power of the second lens group becomes weak, the curvature of field becomes insufficiently corrected and the astigmatic difference increases.
[0011]
Conditional expression (2) relates to the ratio between the focal length of the first lens group and the focal length of the second lens group.
When the lower limit of conditional expression (2) is exceeded, the negative refractive power of the first lens group with respect to the second lens group becomes strong, strong negative distortion occurs, and spherical aberration and coma flare are corrected well. If the upper limit of conditional expression (2) is exceeded, the negative refractive power of the first lens group becomes weak, making it difficult to ensure sufficient back focus, and the field curvature is insufficiently corrected, resulting in a wide angle. It becomes difficult.
[0012]
Conditional expression (3) relates to the ratio between the focal length of the third lens group and the focal length of the second lens group.
If the lower limit of conditional expression (3) is exceeded, the refractive power of the third lens group with respect to the second lens group becomes too strong and the telecentricity becomes good, but the negative distortion becomes large, the field curvature, It becomes difficult to correct the point aberration well. Also, the Petzval sum increases, making it difficult to obtain good image surface performance, and increasing the back focus.
If the upper limit of conditional expression (3) is exceeded, the positive refractive power of the third lens group becomes weak, and at the same time, in order to maintain telecentricity, the refractive power of the positive lens on the image side of the second lens group increases. In particular, it becomes difficult to reduce the occurrence of coma flare in the peripheral portion.
[0013]
Conditional expression (4) is a condition regarding the refractive power distribution of the positive lens and the negative lens constituting the second lens group.
If the lower limit of conditional expression (4) is exceeded, the refractive power of the positive lens in the second lens group becomes too strong, and conversely, the Petzval sum increases due to the reduction of the refractive power of the negative lens, and the field curvature is corrected well. It becomes difficult to do.
If the upper limit of conditional expression (4) is exceeded, the refractive power of the negative lens in the second lens group will increase, making it difficult to reduce spherical aberration and coma.
[0014]
Conditional expression (5) indicates the radius of curvature of the most object side surface of the second lens group (object side surface of the second lens) and the radius of curvature of the most image side surface (image side surface of the fourth lens). It is a condition regarding the ratio.
If the lower limit of conditional expression (5) is exceeded, the radius of curvature of the surface closest to the object will be small, and in particular coma will deteriorate, causing a decrease in contrast.
When the upper limit of conditional expression (5) is exceeded, the radius of curvature of the surface closest to the image side becomes small, and in particular, it becomes difficult to satisfactorily correct field curvature and astigmatism.
[0015]
Conditional expression (6) is a condition regarding the ratio of the air distance between the first lens group and the second lens group (the first lens and the second lens) and the focal length of the first lens group.
If the lower limit of conditional expression (6) is exceeded, it will be difficult to ensure a sufficiently long back focus.
If the upper limit of conditional expression (6) is exceeded, sufficient back focus can be ensured, but it becomes difficult to correct various aberrations, particularly spherical aberration and coma.
[0016]
Conditional expression (7) is a condition regarding the radius of curvature of the object-side surface of the third lens group (positive fifth lens) and the focal length of the third lens group (fifth lens).
By determining the radius of curvature on the object side of the positive fifth lens within the range of conditional expression (7), it becomes possible to ensure good telecentricity without deteriorating various aberrations.
[0017]
Hereinafter, the present invention will be described with respect to specific numerical examples. In each of the following Examples 1 to 5, as shown in each lens configuration diagram, in each case, in order from the object side, the
[0018]
In the various aberration diagrams, d-line, g-line, and C-line indicate wavelengths of spherical aberration, chromatic aberration, and lateral chromatic aberration. In the astigmatism diagram, S represents a sagittal image plane, and M represents a meridional image plane. In the tables and drawings, F NO is the F number, F is the focal length of the entire lens system, W is the half field angle, and f B is the back focus. R is a radius of curvature, D is a lens thickness or a lens interval, N d is a refractive index of d-line, and ν d is an Abbe number. The back focus f B is an air equivalent distance (f B = d 10 + (d 11 / N 11 )) from the final surface (r10 surface) of the third lens group to the image side surface (r12) of the parallel plane glass G. .
[0019]
[Example 1]
FIG. 1 is a lens configuration diagram of a first embodiment of the photographing lens system of the present invention, FIG. 2 is a diagram showing its aberrations, and Table 1 is its numerical data.
[0020]
[Table 1]
[Example 2]
FIG. 3 is a lens configuration diagram of the second embodiment of the photographing lens system of the present invention, FIG. 4 is its aberration diagram, and Table 2 is its numerical data.
[0022]
[Table 2]
[Example 3]
FIG. 5 is a lens configuration diagram of the third example of the photographing lens system of the present invention, FIG. 6 is its aberration diagram, and Table 3 is its numerical data.
[0024]
[Table 3]
[Example 4]
FIG. 7 is a lens configuration diagram of the fourth example of the photographing lens system of the present invention, FIG. 8 is its aberration diagram, and Table 4 is its numerical data.
[0026]
[Table 4]
[Example 5]
FIG. 9 is a lens configuration diagram of the fifth example of the photographing lens system of the present invention, FIG. 10 is its aberration diagram, and Table 5 is its numerical data.
[0028]
[Table 5]
Next, Table 6 shows values for the conditional expressions of Examples 1 to 5.
[Table 6]
As is apparent from Table 6, the numerical values of Examples 1 to 5 satisfy the conditional expressions (1) to (7). Further, as is apparent from the aberration diagrams, each aberration is corrected well, and in particular, the distortion aberration is smaller than that of the photographing lens described in JP-A-3-63613.
[0031]
【The invention's effect】
According to the present invention, it is possible to obtain a wide-angle photographic lens system that has sufficient back focus and high optical performance that can cope with high resolution, has good telecentricity, is compact, and has a small number of components.
[Brief description of the drawings]
FIG. 1 is a lens configuration diagram of a first example of a taking lens system according to the present invention;
2 is a diagram illustrating various aberrations of the photographing lens system in FIG. 1. FIG.
FIG. 3 is a lens configuration diagram of a second example of the taking lens system according to the present invention;
4 is a diagram illustrating various aberrations of the photographic lens system in FIG. 3. FIG.
FIG. 5 is a lens configuration diagram of a third example of the taking lens system according to the present invention.
6 is a diagram illustrating various aberrations of the photographic lens system in FIG. 5. FIG.
FIG. 7 is a lens configuration diagram of a fourth example of the taking lens system according to the present invention.
FIG. 8 is a diagram illustrating various aberrations of the photographing lens system in FIG.
FIG. 9 is a lens configuration diagram of a fifth example of the taking lens system according to the present invention.
10 is a diagram illustrating various aberrations of the photographic lens system in FIG. 9. FIG.
[Explanation of symbols]
10
Claims (2)
（１）１．２＜Ｆ2 ／Ｆ≦１．９０３
（２）１．１＜｜Ｆ1 ／Ｆ2 ｜＜１．７
（３）０．８＜Ｆ3 ／Ｆ2 ≦１．２８４
（４）２．５＜｜（ｆ 2 ＋ｆ 4 ）／ｆ 3 ｜＜３．７
（５）１．３０２≦｜ｒ 3 ／ｒ 8 ｜≦１．５６８
但し、
Ｆ：レンズ全系の焦点距離、
Ｆ1 ：第１レンズ群の焦点距離、
Ｆ2 ：第２レンズ群の焦点距離、
Ｆ3 ：第３レンズ群の焦点距離。
ｆ i ：物体側から第ｉ番目のレンズの焦点距離、
ｒ i ：物体側から第ｉ番目の面の曲率半径。 In order from the object side, a first lens group including a first lens having a negative refractive power; a second lens having a positive refractive power; a third lens having a negative refractive power; and a positive refractive power a second lens group consisting of three groups of three lenses of the fourth lens; and the third lens group including a positive fifth lens; a five-lens configuration of the lens system as a whole consisting of the second lens group The second lens is composed of a positive lens having a convex surface on the object side, and the fourth lens is composed of a positive lens having a convex surface on the image side, and satisfies the following conditional expressions (1) to (5): Taking lens system.
(1) 1.2 <F 2 / F ≦ 1.903
(2) 1.1 <| F 1 / F 2 | <1.7
(3) 0.8 <F 3 / F 2 ≦ 1.284
(4) 2.5 <| (f 2 + F 4 ) / F 3 | <3.7
(5) 1.302 ≦ | r 3 / R 8 | ≦ 1.568
However,
F: focal length of the entire lens system
F 1 : focal length of the first lens group,
F 2 : focal length of the second lens group,
F 3 : focal length of the third lens group.
f i : Focal length of the i-th lens from the object side,
r i : The radius of curvature of the i-th surface from the object side.
（６）０．２５＜｜ｄ2 ／Ｆ1 ｜＜０．５
（７）０．５＜ｒ9 ／Ｆ3 ＜１．０
但し、
ｄ2 ：第１レンズと第２レンズの空気間隔。 2. The photographing lens system according to claim 1, wherein the first lens constituting the first lens group is a meniscus lens having a concave surface on the image side, and the fifth lens constituting the third lens group has a convex surface on the object side. A photographic lens system that includes the positive lens and further satisfies the following conditional expressions (6) and (7).
(6) 0.25 <| d 2 / F 1 | <0.5
(7) 0.5 <r 9 / F 3 <1.0
However,
d 2 : The air space between the first lens and the second lens.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP01664997A JP3723654B2 (en) | 1997-01-30 | 1997-01-30 | Shooting lens system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP01664997A JP3723654B2 (en) | 1997-01-30 | 1997-01-30 | Shooting lens system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH10213742A JPH10213742A (en) | 1998-08-11 |
| JP3723654B2 true JP3723654B2 (en) | 2005-12-07 |
Family
ID=11922207
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP01664997A Expired - Fee Related JP3723654B2 (en) | 1997-01-30 | 1997-01-30 | Shooting lens system |
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| Country | Link |
|---|---|
| JP (1) | JP3723654B2 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102009051831A1 (en) | 2008-11-04 | 2010-05-27 | Hoya Corporation | Wide-angle lens system with rear-lens focus and imaging device equipped with it |
| US8054562B2 (en) | 2008-08-21 | 2011-11-08 | Fujinon Corporation | Imaging lens and imaging apparatus |
| US8355215B2 (en) | 2010-04-12 | 2013-01-15 | Fujifilm Corporation | Image pickup lens and image pickup apparatus |
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|---|---|---|---|---|
| JP3572037B2 (en) * | 2001-08-24 | 2004-09-29 | キヤノン株式会社 | Lens system and optical apparatus having the same |
| JP3943988B2 (en) | 2002-05-15 | 2007-07-11 | キヤノン株式会社 | Lens system and optical apparatus having the same |
| JP2008008960A (en) * | 2006-06-27 | 2008-01-17 | Kyocera Corp | Lens unit |
| JP2011133600A (en) * | 2009-12-24 | 2011-07-07 | Sony Corp | Optical unit and imaging apparatus |
| JP5657696B2 (en) * | 2010-12-21 | 2015-01-21 | 富士フイルム株式会社 | Imaging lens and imaging apparatus |
| US9459430B2 (en) | 2012-03-20 | 2016-10-04 | Microsoft Technology Licensing, Llc | Wide-angle depth imaging lens construction |
| KR101858645B1 (en) | 2012-07-25 | 2018-05-17 | 한화에어로스페이스 주식회사 | Wide angle lens and photographing apparatus with the same |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8054562B2 (en) | 2008-08-21 | 2011-11-08 | Fujinon Corporation | Imaging lens and imaging apparatus |
| DE102009051831A1 (en) | 2008-11-04 | 2010-05-27 | Hoya Corporation | Wide-angle lens system with rear-lens focus and imaging device equipped with it |
| US8169720B2 (en) | 2008-11-04 | 2012-05-01 | Hoya Corporation | Rear focus wide-angle lens system and electronic imaging device using the same |
| US8355215B2 (en) | 2010-04-12 | 2013-01-15 | Fujifilm Corporation | Image pickup lens and image pickup apparatus |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH10213742A (en) | 1998-08-11 |
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