JP3392964B2 - Retro-focus wide-angle lens - Google Patents
Retro-focus wide-angle lensInfo
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- JP3392964B2 JP3392964B2 JP30118594A JP30118594A JP3392964B2 JP 3392964 B2 JP3392964 B2 JP 3392964B2 JP 30118594 A JP30118594 A JP 30118594A JP 30118594 A JP30118594 A JP 30118594A JP 3392964 B2 JP3392964 B2 JP 3392964B2
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- negative
- angle
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Description
【０００１】[0001]
【技術分野】本発明は、レトロフォーカス型の広角レン
ズに関する。TECHNICAL FIELD The present invention relates to a retrofocus wide-angle lens.
【０００２】[0002]
【従来技術及びその問題点】従来、レンズのフォーカシ
ングは、無限遠から近距離まで、レンズ群全体を繰り出
して行なう全体繰り出し式、あるいは、レンズ群の一部
の間隔を変化させて前後群別々に移動させるフローティ
ング式によって、行うものが多かった。しかし、全体繰
り出し式あるいはフローティング式の場合、絞ユニット
も移動するため、鏡筒構成の簡略化という点で問題があ
った。2. Description of the Related Art Conventionally, focusing of a lens is conventionally performed by extending the entire lens group from infinity to a short distance, or by changing a part of the lens group and moving the front and rear groups separately. There were many things to do depending on the floating type. However, in the case of the whole extension type or the floating type, since the diaphragm unit also moves, there is a problem in that the lens barrel structure is simplified.
【０００３】絞位置を固定し、鏡筒構成を簡略化するに
は、前群レンズのみを繰り出す前群レンズ繰り出し式
で、収差を抑えることが望ましい。しかし、前群レンズ
繰り出し式でフォーカシング時の収差変動を抑えるため
には、前群レンズ、後群レンズそれぞれにつき収差係数
の絶対値を小さくしておくことが必要であるが、従来の
レトロフォーカス型広角レンズでは、フォーカシング時
の収差変動を小さく抑えることが困難であった。In order to fix the diaphragm position and simplify the lens barrel structure, it is desirable to suppress aberrations by a front group lens extension type that extends only the front group lens. However, it is necessary to reduce the absolute value of the aberration coefficient for each of the front lens group and the rear lens group in order to suppress the aberration variation during focusing with the front lens group extension type. With a wide-angle lens, it has been difficult to suppress aberration fluctuations during focusing to a small level.
【０００４】[0004]
【発明の目的】本発明は、絞位置を変えることなく、無
限遠から近距離までのフォーカシングによる収差変動を
最小限に抑えることができるレトロフォーカス型の広角
レンズを得ることを目的とする。SUMMARY OF THE INVENTION It is an object of the present invention to obtain a retrofocus type wide-angle lens capable of minimizing aberration variation due to focusing from infinity to a short distance without changing the diaphragm position.
【０００５】[0005]
【発明の概要】本発明のレトロフォーカス型広角レンズ
は、物体側から順に、正の前群レンズと、絞と、正の後
群レンズとによって構成され、フォーカシングは、絞と
後群レンズは移動させることなく、正の前群レンズを移
動させて行ない、正の前群レンズは、負レンズ２枚から
なる負レンズ群と正レンズ群からなり、以下の条件式
（１）ないし（３）を満足することを特徴としている。
（１）０．５＜ｆ／ｆF ＜１．０
（２）−１．２＜ｆ／ｆFN＜−０．７
（３）−０．６＜ｆ／ｆ1 ＜−０．３５
但し、
ｆ：全系の焦点距離、
ｆF ：正の前群レンズの焦点距離、
ｆFN：前群レンズ中の負レンズ群の焦点距離、
ｆ1 ：負レンズ群中の物体側の負レンズの焦点距離、で
ある。SUMMARY OF THE INVENTION A retrofocus wide-angle lens according to the present invention comprises, in order from the object side, a positive front lens group, a diaphragm, and a positive rear lens group. Focusing is performed by moving the diaphragm and the rear lens group. The positive front lens group is moved without moving the positive front lens group. The positive front lens group is composed of a negative lens group composed of two negative lenses and a positive lens group, and the following conditional expressions (1) to (3) are satisfied. Characterized by satisfaction. (1) 0.5 <f / f F <1.0 (2) -1.2 <f / f FN <-0.7 (3) -0.6 <f / f 1 <-0.35 , F: focal length of the entire system, f F : focal length of the positive front lens group, f FN : focal length of the negative lens group in the front lens group, f 1 : of the negative lens on the object side in the negative lens group The focal length is.
【０００６】[0006]
【０００７】さらに、前群レンズ中の第１負レンズは、
次の条件式（４）を満足することが好ましい。
（４）１．８＜ｎ
但し、
ｎ：ｄ線に対する屈折率、
である。Further, the first negative lens in the front lens group is
It is preferable to satisfy the following conditional expression (4). (4) 1.8 <n where n is the refractive index for the d-line.
【０００８】また、前群レンズ中の正レンズ群は、正レ
ンズ２枚から構成することが望ましい。It is desirable that the positive lens group in the front lens group is composed of two positive lenses.
【０００９】[0009]
【発明の実施例】本発明のレトロフォーカス型広角レン
ズは、物体側より順に、正の前群レンズ、絞、及び正の
後群レンズからなるものであり、前群レンズに正のパワ
ーを与えたこと、及びこの前群正レンズを負レンズ群と
正レンズ群とから構成し、これらに条件式（１）及び
（２）を満たす屈折力を与えたことに第一の特徴があ
る。このようなパワー配置とすることにより、前群レン
ズ内の収差係数の絶対値を小さくすることができ、フォ
ーカシング時の収差変動を抑えることができる。本発明
とは逆に、前群レンズのパワーを負としたときには、フ
ォーカシングに伴う収差変動が大きい。The retrofocus wide-angle lens of the present invention comprises a positive front lens group, an aperture stop, and a positive rear lens group in order from the object side, and gives a positive power to the front lens group. The first characteristic is that the front lens group positive lens is composed of a negative lens group and a positive lens group, and is given a refracting power that satisfies the conditional expressions (1) and (2). With such a power arrangement, it is possible to reduce the absolute value of the aberration coefficient in the front lens group, and it is possible to suppress variation in aberration during focusing. Contrary to the present invention, when the power of the front lens group is set to a negative value, the aberration variation associated with focusing is large.
【００１０】条件式（１）の上限を越えると、コマ収差
が補正しきれなくなる。下限を越えると、フォーカシン
グ時のレンズ移動量が大きくなり、また、収差変動が大
きくなる。If the upper limit of conditional expression (1) is exceeded, coma cannot be completely corrected. When the value goes below the lower limit, the amount of lens movement during focusing becomes large, and the aberration variation becomes large.
【００１１】条件式（２）の上限を越えると、歪曲収差
（負）は小さくなるが、バックフォーカスが十分得られ
なくなる。下限を越えると、負のパワーが強すぎ、歪曲
収差（負）が補正しきれなくなる。If the upper limit of conditional expression (2) is exceeded, distortion (negative) becomes small, but sufficient back focus cannot be obtained. If the value goes below the lower limit, the negative power becomes too strong, and the distortion aberration (negative) cannot be completely corrected.
【００１２】一方、画角及びバックフォーカスを一定以
上とするためには、発散系の中の負レンズのパワーを大
きくする、すなわち負レンズの曲率半径を小さくする必
要がある。ところが、負レンズの曲率半径を小さくする
と、大きい歪曲収差の発生が避けられず、これを補正す
るために、通常、発散系の中に正の屈折力のレンズを加
えるが、一定以上のバックフォーカスを得るためには、
さらに負レンズの曲率半径を小さくしなければならず、
その結果、球面収差、コマ収差等に与える悪影響が大き
くなる。On the other hand, in order to keep the angle of view and the back focus above a certain level, it is necessary to increase the power of the negative lens in the diverging system, that is, to reduce the radius of curvature of the negative lens. However, if the radius of curvature of the negative lens is made small, the occurrence of large distortion is unavoidable, and in order to correct this, a lens of positive refractive power is usually added to the divergence system, but a back focus above a certain level. To get
Furthermore, the radius of curvature of the negative lens must be reduced,
As a result, adverse effects on spherical aberration, coma, and the like are increased.
【００１３】本発明は、その一態様によると、前群レン
ズ中の発散系である負レンズ群を２枚の負レンズから構
成することにより、負のパワーを分散させ、歪曲収差を
補正している。条件式（３）の上限を越えると、非点収
差が補正しきれなくなり、下限を越えると第１負レンズ
の曲率半径が小さくなり過ぎ、加工が困難になる。According to one aspect of the present invention, the negative lens group, which is a divergent system in the front lens group, is composed of two negative lenses to disperse the negative power and correct distortion. There is. If the upper limit of conditional expression (3) is exceeded, astigmatism cannot be completely corrected, and if the lower limit of the conditional expression (3) is exceeded, the radius of curvature of the first negative lens becomes too small, which makes processing difficult.
【００１４】また、本発明は、前群レンズ中の正レンズ
を２枚にすることにより、絞より遠い位置に凸面を位置
させることができ、そのために、歪曲収差を補正するこ
とができる。さらに、Ｆ１．４程度の大口径のレンズに
おいて球面収差、コマ収差等の補正ができる。Further, according to the present invention, by using two positive lenses in the front lens group, it is possible to position the convex surface at a position farther than the diaphragm, and therefore distortion can be corrected. Furthermore, it is possible to correct spherical aberration, coma and the like in a lens having a large aperture of about F1.4.
【００１５】さらに、第１負レンズの屈折率を条件式
（４）のように定めることによって、、第１負レンズの
曲率半径が小さくなり過ぎるのを防ぐことができる。Further, by defining the refractive index of the first negative lens as in conditional expression (4), it is possible to prevent the radius of curvature of the first negative lens from becoming too small.
【００１６】次に、具体的な実施例について本発明を説
明する。
［実施例１］図１は、本発明のレトロフォーカス型レン
ズの第１の実施例を示すもので、全体として正の前群レ
ンズ１０と、全体として正の後群レンズ２０の間に、絞
Ｓが配置されている。前群レンズ１０は、物体側より順
に、負レンズ群を構成する第１負レンズ１１と第２負レ
ンズ１２、及び正レンズ群を構成する第１正レンズ１３
と第２正レンズ１４からなっている。後群レンズ２０
は、負レンズ２１、正レンズ２２、及び正レンズ２３か
らなっている。正レンズ２３の後方には、平行平面板
（カバーガラス）２４が位置している。この平行平面板
２４の像側の面は像面である。この平行平面板２４は除
去することができる。フォーカシングは、無限遠から近
距離にかけて、前群レンズ１０のみを前進させて行な
う。絞Ｓ及び後群レンズ２０は、移動しない。Next, the present invention will be described with reference to specific examples. [Embodiment 1] FIG. 1 shows a first embodiment of the retrofocus lens according to the present invention. S is arranged. The front lens group 10 includes, in order from the object side, a first negative lens 11 and a second negative lens 12 that form a negative lens group, and a first positive lens 13 that forms a positive lens group.
And the second positive lens 14. Rear lens group 20
Is composed of a negative lens 21, a positive lens 22, and a positive lens 23. A plane parallel plate (cover glass) 24 is located behind the positive lens 23. The image-side surface of the plane-parallel plate 24 is the image surface. This plane-parallel plate 24 can be removed. Focusing is performed by moving only the front lens group 10 forward from infinity to a short distance. The diaphragm S and the rear lens group 20 do not move.
【００１７】このレンズ系の具体的数値データを表１に
示し、無限遠と最短撮影距離（物体から第１面迄の距離
=100) における諸収差をそれぞれ図２及び図３に示す。
諸収差図中、ＳＡは球面収差、ＳＣは正弦条件、ｄ線、
ｇ線、ｃ線は、それぞれの波長における、球面収差によ
って示される色収差と倍率色収差、Ｓはサジタル、Ｍは
メリディオナルを示している。Specific numerical data of this lens system are shown in Table 1, infinity and the shortest shooting distance (distance from the object to the first surface).
= 100) various aberrations are shown in Figs. 2 and 3, respectively.
In the various aberration diagrams, SA is spherical aberration, SC is sine condition, d line,
Lines g and c represent chromatic aberration and chromatic aberration of magnification indicated by spherical aberration at respective wavelengths, S is sagittal, and M is meridional.
【００１８】表および図面中、FNO はＦナンバー、f は
焦点距離、ωは半画角、Ｙは像高、fBはバックフォーカ
ス、fBP は平行平面板２４の像側の面と像面の距離を表
す。Ｒは曲率半径、Ｄはレンズ間隔、Ｎd はｄ線の屈折
率、νd はｄ線のアッベ数を示す。In the table and drawings, F NO is an F number, f is a focal length, ω is a half angle of view, Y is an image height, f B is a back focus, and f BP is an image side surface of the plane-parallel plate 24 and an image. Shows the distance between faces. R is the radius of curvature, D is the lens spacing, N d is the d-line refractive index, and ν d is the d-line Abbe number.
【００１９】[0019]
【表１】FNO=1:1.4
f=3.54
ω=42.8 ゜(Y=3.0)
fB=d14+d15=4.51
fBP=0
面 No. Ｒ Ｄ Ｎd νd
1 12.342 0.90 1.88300 40.8
2 4.161 2.83 - -
3 45.985 0.70 1.65844 50.9
4 5.830 1.44 - -
5 76.110 1.99 1.83481 42.7
6 -9.600 1.10 - -
7 9.066 2.31 1.77250 49.6
8 -10.447 0.70 - -
絞 ∞ 1.82 - -
9 -5.310 0.70 1.84666 23.8
10 6.564 0.28 - -
11 24.750 2.19 1.77250 49.6
12 -5.310 0.10 - -
13 10.770 2.41 1.77250 49.6
14 -17.646 3.22 - -
15 ∞ 1.29 1.51633 64.1
16 ∞ −
− −[Table 1] F NO = 1: 1.4 f = 3.54 ω = 42.8 ° (Y = 3.0) f B = d 14 + d 15 = 4.51 f BP = 0 Face No. RD N d ν d 1 12.342 0.90 1.88300 40.8 2 4.161 2.83--3 45.985 0.70 1.65844 50.9 4 5.830 1.44--5 76.110 1.99 1.83481 42.7 6 -9.600 1.10--7 9.066 2.31 1.77250 49.6 8 -10.447 0.70--Aperture ∞ 1.82--9 -5.310 0.70 1.84666 23.8 10 6.564 0.28--11 24.750 2.19 1.77250 49.6 12 -5.310 0.10--13 10.770 2.41 1.77250 49.6 14 -17.646 3.22--15 ∞ 1.29 1.51633 64.1 16 ∞-
− −
【００２０】本実施例では、前群レンズ１０でフォーカ
シングを行なう場合、無限遠のときｄ８＝０．７０ 、
最短撮影距離（物体から第１面までの距離＝100)のとき
d8=0.85 、つまりΔd8=0.15 と非常に小さい。これに対
し、前群レンズ１０中の第１負レンズ１１、第２負レン
ズ１２及び第１正レンズ１３（全体として負レンズ群）
だけをフォーカスレンズ群として、移動させる場合、Δ
d6は、1.72(d6=1.10→2.82) と非常に大きくなる。この
場合の諸収差図を参考データとして図４に示す。この諸
収差図から、負レンズ群をフォーカスレンズ群としたと
きには、無限遠から最短撮影距離迄のフォーカシングに
伴う収差変動が大きいことが分かる。In this embodiment, when focusing is performed by the front lens group 10, d8 = 0.70 at infinity,
At the shortest shooting distance (distance from object to first surface = 100)
d8 = 0.85, that is, Δd8 = 0.15, which is very small. On the other hand, the first negative lens 11, the second negative lens 12, and the first positive lens 13 in the front lens group 10 (negative lens group as a whole)
When moving only the focus lens group, Δ
d6 is extremely large at 1.72 (d6 = 1.10 → 2.82). FIG. 4 shows various aberration diagrams in this case as reference data. From these various aberration diagrams, it can be seen that when the negative lens unit is used as the focus lens unit, the aberration variation due to focusing from the infinity to the shortest shooting distance is large.
【００２１】［実施例２］図５は、本発明のレトロフォ
ーカス型レンズの第２の実施例を示す。基本的なレンズ
構成は、図１の第１の実施例と同一である。このレンズ
系の具体的数値データを表２に示し、無限遠と最短撮影
距離（物体から第１面迄の距離＝100)における諸収差を
それぞれ図６及び図７に示す。[Embodiment 2] FIG. 5 shows a second embodiment of the retrofocus lens of the present invention. The basic lens structure is the same as that of the first embodiment shown in FIG. Specific numerical data of this lens system are shown in Table 2, and various aberrations at infinity and the shortest shooting distance (distance from the object to the first surface = 100) are shown in FIGS. 6 and 7, respectively.
【００２２】[0022]
【表２】FNO=1:1.4 f=3.51 ω=43.4 ゜(Y=3.0) fB=d14+d15=3.85 fBP=0 面 NO Ｒ Ｄ Ｎd νd 1 12.715 0.90 1.88300 40.8 2 4.094 3.00 - - 3 53.677 0.70 1.60311 60.7 4 5.267 1.02 - - 5 34.434 1.88 1.83481 42.7 6 -11.890 0.42 - - 7 7.506 2.42 1.77250 49.6 8 -9.699 0.70 - - 絞 ∞ 1.66 - - 9 -4.732 0.70 1.84666 23.8 10 6.704 0.17 - - 11 18.734 2.27 1.77250 49.6 12 -4.847 0.10 - - 13 9.428 3.04 1.77250 49.6 14 -24.851 2.56 - - 15 ∞ 1.29 1.51633 64.1 16 ∞ - - - [Table 2] F NO = 1: 1.4 f = 3.51 ω = 43.4 ° (Y = 3.0) f B = d 14 + d 15 = 3.85 f BP = 0 Face NO RD Nd νd 1 12.715 0.90 1.88300 40.8 2 4.094 3.00 --3 53.677 0.70 1.60311 60.7 4 5.267 1.02--5 34.434 1.88 1.83481 42.7 6 -11.890 0.42--7 7.506 2.42 1.77250 49.6 8 -9.699 0.70--Aperture ∞ 1.66--9 -4.732 0.70 1.84666 23.8 10 6.704 0.17-- 11 18.734 2.27 1.77250 49.6 12 -4.847 0.10--13 9.428 3.04 1.77250 49.6 14 -24.851 2.56--15 ∞ 1.29 1.51633 64.1 16 ∞---
【００２３】本実施例では、前群レンズ１０でフォーカ
シングを行なう場合、無限遠のときd8=0.70 、最短撮影
距離のときd8=0.85 、つまりΔd8=0.15 と非常に小さ
い。これに対し、前群レンズ１０中の第１負レンズ１
１、第２負レンズ１２及び第１正レンズ１３（全体とし
て負レンズ群）だけをフォーカスレンズ群として、移動
させる場合、Δd6は、0.81(d6=0.42→1.23) と非常に大
きくなる。この場合の諸収差図を参考データとして図８
に示す。この諸収差図から、負レンズ群をフォーカスレ
ンズ群としたときには、無限遠から最短撮影距離迄のフ
ォーカシングに伴う収差変動が大きいことが分かる。In this embodiment, when focusing is performed by the front lens group 10, d8 = 0.70 at infinity and d8 = 0.85 at the shortest shooting distance, that is, Δd8 = 0.15, which is very small. On the other hand, the first negative lens 1 in the front lens group 10
When only the first, second negative lens 12 and the first positive lens 13 (the negative lens group as a whole) are moved as the focus lens group, Δd6 becomes very large as 0.81 (d6 = 0.42 → 1.23). FIG. 8 shows various aberration diagrams in this case as reference data.
Shown in. From these various aberration diagrams, it can be seen that when the negative lens unit is used as the focus lens unit, the aberration variation due to focusing from the infinity to the shortest shooting distance is large.
【００２４】表３に、各条件式（１）ないし（４）の数
値を、各実施例について示す。Table 3 shows the numerical values of the conditional expressions (1) to (4) for each example.
【表３】 [Table 3]
【００２５】表３から明らかなように、実施例１及び実
施例２の各数値は、条件式（１）ないし（４）を満足し
ている。また本発明のレトロフォーカス型広角レンズ
は、諸収差図に示すように、無限遠及び最短撮影距離に
おいて、それぞれ諸収差がよく補正されている。As is clear from Table 3, the numerical values of Example 1 and Example 2 satisfy the conditional expressions (1) to (4). Further, in the retrofocus wide-angle lens of the present invention, as shown in various aberration diagrams, various aberrations are well corrected at infinity and the shortest shooting distance.
【００２６】[0026]
【発明の効果】本発明によれば、絞位置を移動させるこ
となく、無限遠から近距離までのフォーカシングによる
収差変動を最小限に抑えることができるレトロフォーカ
ス型広角レンズを提供することができる。According to the present invention, it is possible to provide a retrofocus wide-angle lens capable of minimizing the aberration variation due to focusing from infinity to a short distance without moving the diaphragm position.
【図１】本発明によるレトロフォーカス型広角レンズの
第１の実施例を示すレンズ構成図である。FIG. 1 is a lens configuration diagram showing a first embodiment of a retrofocus wide-angle lens according to the present invention.
【図２】図１のレトロフォーカス型広角レンズの無限遠
撮影距離における諸収差図である。FIG. 2 is a diagram of various aberrations of the retrofocus wide-angle lens of FIG. 1 at an infinite shooting distance.
【図３】図１のレトロフォーカス型広角レンズの最短撮
影距離における諸収差図である。FIG. 3 is a diagram of various types of aberration at the shortest shooting distance of the retrofocus wide-angle lens in FIG.
【図４】図１のレトロフォーカス型広角レンズにおい
て、前群レンズ中の物体側の３枚のレンズ群（全体とし
て負）をフォーカスレンズ群とした場合の諸収差図（参
考図）である。FIG. 4 is a diagram of various aberrations (reference diagram) in the retrofocus wide-angle lens of FIG. 1 when three object-side lens groups (all negative) in the front lens group are used as focus lens groups.
【図５】本発明によるレトロフォーカス型広角レンズの
第２の実施例を示すレンズ構成図である。FIG. 5 is a lens configuration diagram showing a second embodiment of the retrofocus wide-angle lens according to the present invention.
【図６】図５のレトロフォーカス型広角レンズの無限遠
撮影距離における諸収差図である。6 is a diagram of various types of aberration at the infinite shooting distance of the retrofocus wide-angle lens in FIG.
【図７】図５のレトロフォーカス型広角レンズの最短撮
影距離における諸収差図である。FIG. 7 is a diagram of various types of aberration at the shortest shooting distance of the retrofocus wide-angle lens in FIG.
【図８】図５のレトロフォーカス型広角レンズにおい
て、前群レンズ中の物体側の３枚のレンズ群（全体とし
て負）をフォーカスレンズ群とした場合の諸収差図（参
考図）である。8 is a diagram of various aberrations (reference diagram) in the retrofocus wide-angle lens of FIG. 5 when three object-side lens groups (totally negative) in the front lens group are used as focus lens groups.
１０ 前群レンズ １１ 第１負レンズ １２ 第２負レンズ １３ 第１正レンズ １４ 第２正レンズ ２０ 後群レンズ Ｓ 絞 10 front lens 11 First negative lens 12 Second negative lens 13 1st positive lens 14 Second positive lens 20 Rear lens group S aperture
───────────────────────────────────────────────────── フロントページの続き (58)調査した分野(Int.Cl.7，ＤＢ名) G02B 9/00 - 17/08 G02B 21/02 - 21/04 G02B 25/00 - 25/04 ─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields surveyed (Int.Cl. 7 , DB name) G02B 9/00-17/08 G02B 21/02-21/04 G02B 25/00-25/04
Claims (3)
と、正の後群レンズとによって構成され、 フォーカシングは、絞と後群レンズは移動させることな
く、正の前群レンズを移動させて行ない、 正の前群レンズは、負レンズ２枚からなる負レンズ群と
正レンズ群からなり、 以下の条件式（１）ないし（３）を満足することを特徴
とするレトロフォーカス型広角レンズ。 （１）０．５＜ｆ／ｆF ＜１．０ （２）−１．２＜ｆ／ｆFN＜−０．７（３）−０．６＜ｆ／ｆ 1 ＜−０．３５ 但し、 ｆ：全系の焦点距離、 ｆF ：正の前群レンズの焦点距離、 ｆFN：前群レンズ中の負レンズ群の焦点距離、ｆ 1 ：負レンズ群中の物体側の負レンズの焦点距離。 1. A positive front lens group, an aperture stop, and a positive rear lens group in order from the object side. Focusing is performed by moving the positive front lens group without moving the diaphragm and the rear lens group. The positive front lens group, which is moved, is composed of a negative lens group consisting of two negative lenses and a positive lens group, and is characterized by satisfying the following conditional expressions (1) to (3). Wide-angle lens. (1) 0.5 <f / f F <1.0 (2) -1.2 <f / f FN <-0.7 (3) -0.6 <f / f 1 <-0.35 , F: focal length of the entire system, f F : focal length of the positive front lens group, f FN : focal length of the negative lens group in the front lens group, f 1 : of the negative lens on the object side in the negative lens group Focal length.
レンズにおいて、前群レンズ中の正レンズ群は、正レン
ズ２枚からなるレトロフォーカス型広角レンズ。2. The retrofocus wide-angle lens according to claim 1, wherein the positive lens group in the front lens group is composed of two positive lenses.
レンズにおいて、前群レンズ中の第１負レンズは、以下
の条件式（４）を満足するレトロフォーカス型広角レン
ズ。 （４）１．８＜ｎ 但し、 ｎ：ｄ線に対する屈折率。3. The retrofocus wide-angle lens according to claim 2, wherein the first negative lens in the front lens group satisfies the following conditional expression (4). (4) 1.8 <n where n: refractive index for d-line.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP30118594A JP3392964B2 (en) | 1993-12-08 | 1994-12-05 | Retro-focus wide-angle lens |
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP30797993 | 1993-12-08 | ||
| JP5-307979 | 1993-12-08 | ||
| JP30118594A JP3392964B2 (en) | 1993-12-08 | 1994-12-05 | Retro-focus wide-angle lens |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH07218826A JPH07218826A (en) | 1995-08-18 |
| JP3392964B2 true JP3392964B2 (en) | 2003-03-31 |
Family
ID=26562592
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP30118594A Expired - Lifetime JP3392964B2 (en) | 1993-12-08 | 1994-12-05 | Retro-focus wide-angle lens |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3392964B2 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2397880A2 (en) | 2010-06-16 | 2011-12-21 | Ricoh Company, Ltd. | Image-forming lens, and camera device and portable information terminal device with the image-forming lens |
| US8681436B2 (en) | 2010-12-13 | 2014-03-25 | Ricoh Company, Ltd. | Imaging lens, imaging device and information device |
| US9615008B2 (en) | 2012-12-26 | 2017-04-04 | Fujifilm Corporation | Imaging lens and imaging apparatus equipped with the same |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP6576427B2 (en) * | 2017-11-18 | 2019-09-18 | エーエーシー テクノロジーズ ピーティーイー リミテッド | Imaging optical lens |
| JP6576425B2 (en) * | 2017-11-18 | 2019-09-18 | エーエーシー テクノロジーズ ピーティーイー リミテッド | Imaging optical lens |
| CN113176655B (en) * | 2021-04-29 | 2023-10-13 | 江西欧菲光学有限公司 | Optical system, camera module, camera equipment and carrier |
-
1994
- 1994-12-05 JP JP30118594A patent/JP3392964B2/en not_active Expired - Lifetime
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2397880A2 (en) | 2010-06-16 | 2011-12-21 | Ricoh Company, Ltd. | Image-forming lens, and camera device and portable information terminal device with the image-forming lens |
| US9606324B2 (en) | 2010-06-16 | 2017-03-28 | Ricoh Company, Ltd. | Image-forming lens, and camera device and portable information terminal device with the image-forming lens |
| US8681436B2 (en) | 2010-12-13 | 2014-03-25 | Ricoh Company, Ltd. | Imaging lens, imaging device and information device |
| US9615008B2 (en) | 2012-12-26 | 2017-04-04 | Fujifilm Corporation | Imaging lens and imaging apparatus equipped with the same |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH07218826A (en) | 1995-08-18 |
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