JP4789473B2 - Super wide-angle lens system - Google Patents
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Description
本発明は、超広角レンズ系に関し、特に６４５版程度の中版カメラ用に好適な超広角レンズ系に関する。 The present invention relates to an ultra-wide-angle lens system, and more particularly to an ultra-wide-angle lens system suitable for a middle-format camera of about 645 plates.
従来、ライカ版（３５ｍｍ版）用の超広角レンズ系として、例えば特開平５−３４５９２号公報が提案されている。この超広角レンズ系はしかし、画面サイズが約１．６倍の中版カメラ用にスケーリングすると、収差及び大きさが１．６倍になってしまい、光学性能が劣り、小型化も困難であった。その他には、特開平４−２４６６０６号公報、特開平５−３２３１８３号公報、特開平９−８０３０３号公報などが知られているが、これらはディストーションの補正が不十分である上、焦点距離に比べて全長が極めて長くなり、中判カメラ用には使えない。
本発明は、Ｆナンバーが４から４．５程度で半画角が５２度程度を有する中版カメラ用に好適な小型の超広角レンズ系を得ることを目的とする。 An object of the present invention is to obtain a small super-wide-angle lens system suitable for a mid-size camera having an F number of about 4 to 4.5 and a half field angle of about 52 degrees.
本発明の超広角レンズ系は、物体側から順に、フォーカシング時に不動の正または負のパワーの前群、絞り、及びフォーカスレンズ群である正のパワーの後群からなり、前群は、物体側から順に、該前群を構成する各レンズからの近軸軸上光線の射出傾角のうち負の最大値のところで分けられた負のパワーの第１ａレンズ群と、正のパワーの第１ｂレンズ群とを有し、次の条件式（１）及び（２）を満足すること、及び後群は、物体側から順に、空気間隔が最大のところで分けられた可動の正の第２ａレンズ群と、可動の正の第２ｂレンズ群とを有し、フォーカシングのとき、この第２ａレンズ群と第２ｂレンズ群が次の条件式（４）を満足するように互いに独立して移動すること、を特徴としている。
（１）ｆ／｜ｆＦ｜＜０．４５
（２）０．９＜ｆ／｜ｆ１ａ｜＜２．５
（４）０．２＜Ｘ２ａｎ／Ｘ２ｂｎ＜０．８
但し、
ｆ；全系の焦点距離、
ｆＦ；前群の焦点距離、
ｆ１ａ；第１ａレンズ群の焦点距離（ｆ１ａ＜０）、
Ｘ２ａｎ；無限遠物体から最短距離物体に向けてフォーカシングするときの第２ａレンズ群の移動量、
Ｘ２ｂｎ；無限遠物体から最短距離物体に向けてフォーカシングするときの第２ｂレンズ群の移動量、
である。
The super wide-angle lens system of the present invention includes, in order from the object side, a front group of positive or negative power that does not move during focusing , a stop, and a rear group of positive power that is a focus lens group. In order, the negative power 1a lens group and the positive power 1b lens group, which are divided at the negative maximum value among the emission tilt angles of the paraxial axial rays from the respective lenses constituting the front group, Satisfying the following conditional expressions (1) and (2), and the rear group, in order from the object side, a movable positive second a lens group divided at a maximum air interval; A movable positive second b lens group, and during focusing, the second a lens group and the second b lens group move independently of each other so as to satisfy the following conditional expression (4): It is said.
(1) f / | fF | <0.45
(2) 0.9 <f / | f1a | <2.5
(4) 0.2 <X2an / X2bn <0.8
However,
f: focal length of the entire system
fF: Focal length of the front group,
f1a: focal length of the 1a lens group (f1a <0),
X2an: the amount of movement of the 2a lens group when focusing from the object at infinity toward the object at the shortest distance,
X2bn: the amount of movement of the second lens group when focusing from the object at infinity toward the object at the shortest distance,
It is.
さらに、本発明の超広角レンズ系において、次の条件式（３）を満足することが好ましい。
（３）０．９＜ｄ1a-1b／ｆ＜２．１
但し、
ｄ1a-1b；第１ａレンズ群の最も物体側の面から第１ｂレンズ群の最も物体側の面までの距離、
である。
Furthermore, in the super wide-angle lens system of the present invention, it is preferable that the following conditional expression (3) is satisfied.
(3) 0.9 <d 1a-1b /f<2.1
However,
d 1a-1b ; distance from the most object side surface of the 1a lens group to the most object side surface of the 1b lens group;
It is.
第１ａレンズ群は、物体側から順に、物体側に凸面を向けた２枚または３枚の負メニスカスレンズからなることが好ましい。 It is preferable that the 1a lens group includes two or three negative meniscus lenses having a convex surface directed toward the object side in order from the object side.
後群には、第２ｂレンズ群の更に像側に、フォーカシング時に移動しない正または負の固定レンズを配置することができる。 In the rear group, a positive or negative fixed lens that does not move during focusing can be disposed further on the image side of the second b lens group.
前群中、後群中には、それぞれ非球面を配置するのがよい。 An aspherical surface is preferably arranged in each of the front group and the rear group.
前群の非球面は、第１ａレンズ群内のいずれかの負メニスカスレンズに設けられることが好ましい。 The aspherical surface of the front group is preferably provided on any negative meniscus lens in the 1a lens group.
後群には、少なくとも１枚の正レンズが含まれ、かつ、その正レンズのうちの少なくとも１枚が、次の条件式（９）を満足することが好ましい。
（９）νRp＞８０
但し、
νRp；後群中に含まれる正レンズのアッベ数、
である。
The rear group preferably includes at least one positive lens, and at least one of the positive lenses preferably satisfies the following conditional expression (9).
(9) ν Rp > 80
However,
ν Rp ; Abbe number of the positive lens included in the rear group,
It is.
本発明によれば、Ｆナンバーが４ないし４．５程度で半画角約５２度程度を有する小型の超広角レンズ系を得ることができる。 According to the present invention, a small super wide-angle lens system having an F number of about 4 to 4.5 and a half angle of view of about 52 degrees can be obtained.
本発明の超広角レンズ系は、図１（実施例１）、図３（実施例２）、図５（実施例３）、図７（実施例４）、図９（実施例５）、図１１（実施例６）、図１３（実施例７）の各実施例のレンズ構成図に示すように、物体側から順に、正負のパワーを問わない（正負いずれのパワーもとりうる）前群１０、絞りＳ、及び正のパワーの後群２０からなっている。前群１０は、物体側から順に、各レンズからの近軸軸上光線の射出傾角のうち負の最大値のところで分けられた物体側の負のパワーの第１ａレンズ群と、像側の正のパワーの第１ｂレンズ群からなる。射出傾角の符号は、発散方向を負とする。後群２０は、物体側から順に、空気間隔が最大のところで分けられた正の第２ａレンズ群２１と、正の第２ｂレンズ群２２とを有している。実施例１、２、３、６、７では、後群２０は、物体側から順に、第２ａレンズ群２１と第２ｂレンズ群２２だけからなっているのに対し、実施例４、５では、第２ｂレンズ群の像側にさらに、正または負の第２ｃレンズ群２３を有している。 The super wide-angle lens system of the present invention is shown in FIG. 1 (Example 1), FIG. 3 (Example 2), FIG. 5 (Example 3), FIG. 7 (Example 4), FIG. 11 (Embodiment 6), as shown in the lens configuration diagram of each embodiment of FIG. 13 (Embodiment 7) , the front group 10 regardless of whether the power is positive or negative (possibly positive or negative power) in order from the object side. It consists of a stop S and a rear group 20 of positive power. The front group 10 includes, in order from the object side, a first-a lens group of negative power on the object side divided at the negative maximum value among the emission tilt angles of paraxial axial rays from each lens, and a positive lens on the image side. The first-b lens group having the following power. The sign of the emission inclination is negative in the divergence direction. The rear group 20 includes, in order from the object side, a positive second a lens group 21 and a positive second b lens group 22 that are separated at the maximum air gap. In Examples 1, 2, 3, 6, and 7, the rear group 20 includes only the second a lens group 21 and the second b lens group 22 in order from the object side, whereas in Examples 4 and 5, A positive or negative second c lens group 23 is further provided on the image side of the second b lens group.
以上の実施例１から実施例７では、フォーカシングに際し、第２ａレンズ群２１と第２ｂレンズ群２２が独立して動く点が特徴の一つであり、第２ｃレンズ群２３は不動である。図１５は、本超広角レンズ系の実施例１から実施例７におけるフォーカシング簡易移動図である。同図の上方（ＩＮＦ）は無限遠物体合焦時、下方（ＮＥＡＲ）は最短撮影距離物体合焦時の状態を示しており、無限遠物体への合焦状態から最短撮影距離物体に合焦するのに際し、第２ａレンズ群２１と第２ｂレンズ群２２が独立して、かつ第２ｂレンズ群２２の移動量が第２ａレンズ群２１の移動量より大きいように移動する。絞りＳは、第２ａレンズ群２１と一緒に移動する。第２ｃレンズ群２３が存在する態様（実施例４、５）では、該第２ｃレンズ群２３は移動しない（図１５中の破線で示す）。 In the first to seventh embodiments, one of the features is that the second a lens group 21 and the second b lens group 22 move independently during focusing, and the second c lens group 23 does not move. FIG. 15 is a focusing simple movement diagram in the first to seventh embodiments of the super wide-angle lens system. The upper part (INF) of the figure shows the state when the object at infinity is in focus, and the lower part (NEAR) shows the state when the object at the shortest shooting distance is in focus. In doing so, the second-a lens group 21 and the second-b lens group 22 are moved independently so that the movement amount of the second-b lens group 22 is larger than the movement amount of the second-a lens group 21. The stop S moves together with the 2a lens group 21. In the mode in which the second c lens group 23 exists (Examples 4 and 5), the second c lens group 23 does not move (indicated by a broken line in FIG. 15 ).
また、実施例１〜実施例７では、負のパワーの第１ａレンズ群１１は、物体側から順に、物体側に凸面を向けた２枚（実施例１、４、５、６、７）または３枚（実施例２、３）の負メニスカスレンズからなり、正のパワーの第１ｂレンズ群１２は、実施例１〜５では、物体側から順に、物体側の負レンズと像側の正レンズの接合（貼合せ）レンズと、正レンズとの２群３枚からなり、実施例６、７では、物体側から順に、正レンズ、負レンズ、物体側の負レンズと像側の正レンズの接合レンズ、及び正レンズの４群５枚からなっている。 In the first to seventh embodiments, the negative power first-a lens group 11 includes, in order from the object side, two lenses (Examples 1, 4, 5, 6, and 7) having convex surfaces facing the object side. In the first to fifth embodiments, the first-b lens group 12 having three negative meniscus lenses (Examples 2 and 3) and having a positive power is sequentially arranged from the object side to the object side negative lens and the image side positive lens in Examples 1 to 5. In Examples 6 and 7, the positive lens, the negative lens, the object-side negative lens, and the image-side positive lens are sequentially arranged from the object side. It consists of 5 elements in 4 groups: a cemented lens and a positive lens.
条件式（１）は、前群のパワーに関する条件式である。本超広角レンズ系は、前群のパワーをこの条件式（１）を満足するように比較的弱く設定した点に一つの特徴がある。条件式（１）の上限を超えて前群のパワーが大きくなると、後群全体もしくは後群の一部を移動させてフォーカシングしたときの近距離における収差の劣化が大きくなる。前群のパワーは、正負のいずれもとりうる。 Conditional expression (1) is a conditional expression regarding the power of the front group. This super wide-angle lens system has one feature in that the power of the front group is set relatively weak so as to satisfy the conditional expression (1). When the power of the front group increases beyond the upper limit of the conditional expression (1), the deterioration of aberrations at a short distance increases when the entire rear group or a part of the rear group is moved for focusing. The power of the front group can be positive or negative.
条件式（２）は、前群の第１ａレンズ群のパワーに関する条件式である。条件式（２）の上限を超えると、バックフォーカスの確保には有利となるが、球面収差やコマ収差の高次の収差が発生する。条件式（２）の下限を超えると、歪曲収差の補正が困難となる。 Conditional expression (2) is a conditional expression regarding the power of the 1a lens group in the front group. Exceeding the upper limit of conditional expression (2) is advantageous for securing the back focus, but high-order aberrations such as spherical aberration and coma occur. If the lower limit of conditional expression (2) is exceeded, it will be difficult to correct distortion.
条件式（３）は、第１ａレンズ群の最も物体側の面から第１ｂレンズ群の最も物体側の面までの距離に関する条件式である。条件式（３）の上限を超えると、第１ｂレンズ群の正のパワーを強くせざるを得ず、第１ｂレンズ群で発生する球面収差の補正が困難となる。条件式（３）の下限を超えると、第１ａレンズ群による歪曲収差の補正が困難になる。 Conditional expression (3) is a conditional expression relating to the distance from the most object-side surface of the 1a lens group to the most object-side surface of the 1b lens group. If the upper limit of conditional expression (3) is exceeded, the positive power of the 1b lens group must be increased, and it becomes difficult to correct spherical aberration that occurs in the 1b lens group. If the lower limit of conditional expression (3) is exceeded, it will be difficult to correct distortion by the 1a lens group.
条件式（４）は、後群中の第２ａレンズ群及び第２ｂレンズ群が互いに独立して移動する態様（実施例１〜実施例７）における後群のフォーカシング方式に関する条件式である。図１５で説明したように、本実施形態では、空気間隔最大となるところで後群を分割し、物体側に位置するレンズ群を第２ａレンズ群、像面側に位置するレンズ群を第２ｂレンズ群とし、これらのレンズ群を別々に移動させる。後群の像面側には、固定のレンズ群を配置しても良い。条件式（４）の上限を超えると、第２ａレンズ群と第２ｂレンズ群の移動量が同程度となり、コマ収差、非点収差の補正が困難となる。条件式（４）の下限を超えると、第２ｂレンズ群の移動量が大きくなって、コマ収差、非点収差の補正が過剰となる。 Conditional expression (4) is a conditional expression regarding the focusing method of the rear group in the aspect (Examples 1 to 7) in which the second a lens group and the second b lens group in the rear group move independently of each other. As described with reference to FIG. 15 , in this embodiment, the rear group is divided where the air space becomes maximum, the lens group located on the object side is the 2a lens group, and the lens group located on the image plane side is the 2b lens. These lens groups are moved separately. A fixed lens group may be arranged on the image plane side of the rear group. If the upper limit of conditional expression (4) is exceeded, the movement amounts of the 2a lens group and the 2b lens group will be approximately the same, and it will be difficult to correct coma and astigmatism. When the lower limit of conditional expression (4) is exceeded, the amount of movement of the 2b lens group becomes large, and correction of coma and astigmatism becomes excessive.
条件式（９）は、後群中に含まれる正レンズに関する条件式である。条件式（９）の下限を超えると、軸上色収差、倍率色収差の補正が困難になる。 Conditional expression (9) is a conditional expression regarding the positive lens included in the rear group. If the lower limit of conditional expression (9) is exceeded , it will be difficult to correct longitudinal chromatic aberration and lateral chromatic aberration.
本超広角レンズ系では、後群の最も物体側のレンズの前方に、光束を制限する絞りを配置している。このように後群の最も物体側のレンズの近傍に絞りを配置すると、機械的構成が容易となり後群の機械的精度が向上する。 In the present super-wide-angle lens system, a stop for limiting the luminous flux is disposed in front of the most object-side lens in the rear group. If the stop is arranged in the vicinity of the lens closest to the object side in the rear group as described above, the mechanical configuration becomes easy and the mechanical accuracy of the rear group is improved.
前群中、後群中にはそれぞれ非球面を配置することができ、特に前群中の非球面は第１ａレンズ群内の負メニスカスレンズに設けることにより、短焦点距離端における歪曲収差、非点収差を良好に補正し、かつフォーカシングによる像面湾曲の変動を小さくすることができる。 An aspheric surface can be arranged in each of the front group and the rear group, and in particular, the aspheric surface in the front group is provided on the negative meniscus lens in the 1a lens group, so that distortion at the short focal length end, Astigmatism can be satisfactorily corrected, and fluctuations in field curvature due to focusing can be reduced.
次に具体的な実施例を示す。諸収差図及び表中、ＳＡは球面収差、ＳＣは正弦条件、球面収差で表される色収差（軸上色収差）図及び倍率色収差図中のｄ線、ｇ線、Ｃ線はそれぞれの波長に対する収差、ｙは像高、Ｓはサジタル、Ｍはメリディオナル、ＦはＦナンバー、ｆは全系の焦点距離、Ｗは半画角（°）、ｍは全系の横倍率、ｆBはバックフォーカス、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、νはアッベ数、UNは前群を構成する各レンズからの近軸軸上光線の射出傾角を示す。また、表中のｍ、ｆB及びｄの値は、無限遠物体合焦時、中間距離物体合焦時及び最短距離物体合焦時の値を順に示している。
また、回転対称非球面は次式で定義される。
x=cy2/[1+[1-(1+K)c2y2]1/2]+A4y4+A6y6+A8y8 +A10y10+A12y12・・・
（但し、cは曲率（１／ｒ）、ｙは光軸からの高さ、Ｋは円錐係数、Ａ４、Ａ６、Ａ８
、・・・・・は各次数の非球面係数）
Next, specific examples will be described. In the various aberration diagrams and tables, SA is spherical aberration, SC is a sine condition, chromatic aberration (axial chromatic aberration) diagram represented by spherical aberration, and d-line, g-line, and C-line are chromatic aberrations for each wavelength. , Y is the image height, S is sagittal, M is meridional, F is the F number, f is the focal length of the entire system, W is the half field angle (°), m is the lateral magnification of the entire system, fB is the back focus, r Is the radius of curvature, d is the lens thickness or lens interval, N d is the refractive index of the d-line, ν is the Abbe number, and UN is the exit tilt angle of the paraxial light beam from each lens constituting the front group. Further, the values of m, fB, and d in the table indicate values in order at the time of focusing on an object at infinity, at the time of focusing on an intermediate distance object, and at the time of focusing on an object at the shortest distance.
A rotationally symmetric aspherical surface is defined by the following equation.
x = cy 2 / [1+ [1- (1 + K) c 2 y 2 ] 1/2 ] + A4y 4 + A6y 6 + A8y 8 + A10y 10 + A12y 12 ...
(Where c is the curvature (1 / r), y is the height from the optical axis, K is the conic coefficient, A4, A6, A8
, ... are aspheric coefficients of each order)
図１及び図２と表１は本発明による超広角レンズ系の実施例１を示している。図１はレンズ構成図、図２はその諸収差図、表１はその数値データである。
前群１０は、物体側から順に、負の第１ａレンズ群１１と正の第１ｂレンズ群１２からなる。第１ａレンズ群１１は、いずれも物体側に凸の２枚の負メニスカスレンズからなり、物体側の負メニスカスレンズの像側の面にはプラスチックからなる非球面層が付着形成されている。第１ｂレンズ群１２は、物体側から順に、物体側に位置する物体側に凸の負メニスカスレンズと像側に位置する正レンズとの接合（貼合せ）レンズ、及び正レンズからなる。後群２０は、物体側から順に、第２ａレンズ群２１と第２ｂレンズ群２２からなる。第２ａレンズ群２１は、物体側から順に、正レンズ、及び物体側の正レンズと像側の負レンズとの接合レンズからなり、第２ｂレンズ群２２は、物体側の両凹負レンズと像側の両凸正レンズとの接合レンズからなる。接合レンズの正レンズの像側の面は非球面である。絞りＳは、第１１面（第２ａレンズ群２１）の極から前方1.00にある。
（表１）
F = 1: 4.5
f = 28.95
W = 51.5
m = 0.000 / -0.025 / -0.196
fB = 60.50 / 61.25 / 67.09
面NO. ｒ ｄ Ｎd ν UN
1 91.620 2.00 1.77250 49.6
2 29.000 0.50 1.52972 42.7
3* 22.834 13.15 - - -0.6611
4 120.623 2.00 1.72916 54.7
5 36.263 17.32 - - -1.1967
6 114.358 1.50 1.61800 63.4
7 34.033 9.00 1.77250 49.6
8 4944.811 13.97 - - -0.6202
9 44.023 11.00 1.59240 68.3
10 328.525 11.35-10.57-7.63 - -
11 1343.570 7.00 1.67270 32.1
12 -52.723 0.20 - -
13 -1310.512 3.63 1.60342 38.0
14 -17.452 1.30 1.83481 42.7
15 -153.923 8.89-8.92-6.01 - -
16 -54.758 2.30 1.80518 25.4
17 48.099 7.16 1.59240 68.3
18* -23.174 - - -
*は回転対称非球面。
非球面データ（表示していない非球面係数は0.00である。）；
面NO Ｋ Ａ４ Ａ６
3 -0.10000×10 0.18395×10-5 -0.10608×10-8
18 0.00 0.47627×10-5 0.11853×10-7
Ａ８ Ａ１０
3 0.24368×10-11 -0.24216×10-14
18 -0.27913×10-10 0.10049×10-12
1 and 2 and Table 1 show Example 1 of an ultra-wide-angle lens system according to the present invention. FIG. 1 is a lens configuration diagram, FIG. 2 is a diagram showing aberrations thereof, and Table 1 is numerical data thereof.
The front group 10 includes a negative first lens group 11 and a positive first lens group 12 in order from the object side. The first lens group 11 is composed of two negative meniscus lenses that are convex on the object side, and an aspherical layer made of plastic is attached to the image side surface of the negative meniscus lens on the object side. The 1b lens group 12 includes, in order from the object side, a cemented (bonded) lens of a negative meniscus lens convex on the object side located on the object side and a positive lens located on the image side, and a positive lens. The rear group 20 includes a second-a lens group 21 and a second-b lens group 22 in order from the object side. The second-a lens group 21 includes, in order from the object side, a positive lens and a cemented lens of an object-side positive lens and an image-side negative lens, and the second-b lens group 22 includes a biconcave negative lens and an image on the object side. It consists of a cemented lens with a biconvex positive lens on the side. The image side surface of the positive lens of the cemented lens is aspheric. The stop S is 1.00 ahead from the pole of the eleventh surface (the 2a lens group 21).
(Table 1)
F = 1: 4.5
f = 28.95
W = 51.5
m = 0.000 / -0.025 / -0.196
fB = 60.50 / 61.25 / 67.09
Surface NO. Rd N d ν UN
1 91.620 2.00 1.77250 49.6
2 29.000 0.50 1.52972 42.7
3 * 22.834 13.15---0.6611
4 120.623 2.00 1.72916 54.7
5 36.263 17.32---1.1967
6 114.358 1.50 1.61800 63.4
7 34.033 9.00 1.77250 49.6
8 4944.811 13.97---0.6202
9 44.023 11.00 1.59240 68.3
10 328.525 11.35-10.57-7.63--
11 1343.570 7.00 1.67270 32.1
12 -52.723 0.20--
13 -1310.512 3.63 1.60342 38.0
14 -17.452 1.30 1.83481 42.7
15 -153.923 8.89-8.92-6.01--
16 -54.758 2.30 1.80518 25.4
17 48.099 7.16 1.59240 68.3
18 * -23.174---
* Is a rotationally symmetric aspherical surface.
Aspheric data (Aspheric coefficient not shown is 0.00);
Surface NO K A4 A6
3 -0.10000 × 10 0.18395 × 10 -5 -0.10608 × 10 -8
18 0.00 0.47627 × 10 -5 0.11853 × 10 -7
A8 A10
3 0.24368 × 10 -11 -0.24216 × 10 -14
18 -0.27913 × 10 -10 0.10049 × 10 -12
図３及び図４と表２は本発明による超広角レンズ系の実施例２を示している。図３はレンズ構成図、図４はその諸収差図、表２はその数値データである。この実施例では、第１ａレンズ群１１は、３枚の負メニスカスレンズからなっており、真中の負メニスカスレンズの像側の面にプラスチック非球面層が形成されている。この他のレンズ構成は実施例１と同様である。絞りＳは、第１３面（第２ａレンズ群２１）の極から前方1.00にある。
（表２）
F = 1: 4.5
f = 28.95
W = 51.6
m = 0.000 / -0.025 / -0.193
fB = 60.50 / 61.24 / 66.63
面NO. ｒ ｄ Ｎd ν UN
1 100.000 2.30 1.77250 49.6
2 50.000 3.00 - - -0.2192
3 67.101 2.00 1.77250 49.6
4 27.000 0.50 1.52972 42.7
5* 21.212 10.46 - - -0.8740
6 71.513 2.00 1.72916 54.7
7 41.740 15.31 - - -1.1629
8 104.573 1.50 1.61800 63.4
9 30.542 9.00 1.77250 49.6
10 1350.779 13.85 - - -0.5712
11 46.041 11.00 1.59240 68.3
12 312.317 9.14-8.37-5.17 - -
13 -19406.173 6.74 1.67270 32.1
14 -43.058 0.20 - -
15 -449.398 3.39 1.60342 38.0
16 -15.981 1.30 1.83481 42.7
17 -173.209 9.04-9.06-6.87 - -
18 -46.689 2.30 1.80518 25.4
19 52.298 7.60 1.59240 68.3
20* -20.953 - - -
*は回転対称非球面。
非球面データ（表示していない非球面係数は0.00である。）；
面NO Ｋ Ａ４ Ａ６
5 -0.10000×10 0.23073×10-6 -0.32381×10-9
20 0.00 0.62971×10-5 0.13359×10-7
Ａ８ Ａ１０
5 0.27922×10-11 -0.32359×10-14
20 -0.11413×10-10 0.10958×10-12
3 and 4 and Table 2 show Example 2 of the super wide-angle lens system according to the present invention. FIG. 3 is a lens configuration diagram, FIG. 4 is a diagram showing aberrations thereof, and Table 2 is numerical data thereof. In this embodiment, the first-a lens group 11 is composed of three negative meniscus lenses, and a plastic aspherical layer is formed on the image side surface of the middle negative meniscus lens. Other lens configurations are the same as those in the first embodiment. The stop S is 1.00 ahead from the pole of the thirteenth surface (the 2a lens group 21).
(Table 2)
F = 1: 4.5
f = 28.95
W = 51.6
m = 0.000 / -0.025 / -0.193
fB = 60.50 / 61.24 / 66.63
Surface NO. Rd N d ν UN
1 100.000 2.30 1.77250 49.6
2 50.000 3.00---0.2192
3 67.101 2.00 1.77250 49.6
4 27.000 0.50 1.52972 42.7
5 * 21.212 10.46---0.8740
6 71.513 2.00 1.72916 54.7
7 41.740 15.31---1.1629
8 104.573 1.50 1.61800 63.4
9 30.542 9.00 1.77250 49.6
10 1350.779 13.85---0.5712
11 46.041 11.00 1.59240 68.3
12 312.317 9.14-8.37-5.17--
13 -19406.173 6.74 1.67270 32.1
14 -43.058 0.20--
15 -449.398 3.39 1.60342 38.0
16 -15.981 1.30 1.83481 42.7
17 -173.209 9.04-9.06-6.87--
18 -46.689 2.30 1.80518 25.4
19 52.298 7.60 1.59240 68.3
20 * -20.953---
* Is a rotationally symmetric aspherical surface.
Aspheric data (Aspheric coefficient not shown is 0.00);
Surface NO K A4 A6
5 -0.10000 × 10 0.23073 × 10 -6 -0.32381 × 10 -9
20 0.00 0.62971 × 10 -5 0.13359 × 10 -7
A8 A10
5 0.27922 × 10 -11 -0.32359 × 10 -14
20 -0.11413 × 10 -10 0.10958 × 10 -12
図５及び図６と表３は本発明による超広角レンズ系の実施例３を示している。図５はレンズ構成図、図６はその諸収差図、表３はその数値データである。この実施例の第１ａレンズ群１１の構成は実施例２と同様である。第２ｂレンズ群２２は、物体側から順に、物体側の負レンズと像側の両凸正レンズとの接合レンズ、及び両凹負レンズの３枚構成であり、接合レンズの正レンズの像側の面にプラスチック非球面層が形成されている。この他のレンズ構成は実施例１と同様である。絞りＳは、第１３面（第２ａレンズ群２１）の極から前方1.00にある。
（表３）
F = 1: 4.5
f = 28.95
W = 51.4
m = 0.000 / -0.025 / -0.216
fB = 60.50 / 61.28 / 67.94
面NO. ｒ ｄ Ｎd ν UN
1 83.312 2.30 1.77250 49.6
2 33.849 3.80 - - -0.3843
3 44.953 2.00 1.77250 49.6
4 27.000 0.50 1.52972 42.7
5* 21.452 11.90 - - -0.8764
6 48.599 2.00 1.72916 54.7
7 34.871 19.17 - - -1.1215
8 109.778 1.50 1.61800 63.4
9 27.741 9.00 1.77250 49.6
10 124.947 2.47 - - -0.8232
11 54.458 11.00 1.49700 81.6
12 178.943 11.71-11.60-6.67 - -
13 53.307 10.68 1.68893 31.1
14 -46.946 0.71 - -
15 -82.581 4.00 1.49700 81.6
16 -21.199 1.30 1.88300 40.8
17 -191.146 10.63-9.95-8.23 - -
18 557.880 2.30 1.80518 25.4
19 32.749 8.03 1.59240 68.3
20 -28.700 0.30 1.52972 42.7
21* -27.000 0.20 - -
22 -241.786 3.00 1.77250 49.6
23 397.698 - - -
*は回転対称非球面。
非球面データ（表示していない非球面係数は0.00である。）；
面NO Ｋ Ａ４ Ａ６
5 -0.10000×10 -0.30579×10-6 0.27389×10-8
21 0.00 0.81173×10-5 -0.13710×10-8
Ａ８ Ａ１０
5 -0.63574×10-11 0.14729×10-14
21 0.35186×10-10 -0.54724×10-13
5 and 6 and Table 3 show Example 3 of the super wide-angle lens system according to the present invention. FIG. 5 is a lens configuration diagram, FIG. 6 is a diagram showing aberrations thereof, and Table 3 is numerical data thereof. The configuration of the first-a lens group 11 of this embodiment is the same as that of the second embodiment. The second lens group 22 has a three-lens configuration of a cemented lens of a negative lens on the object side and a biconvex positive lens on the image side and a biconcave negative lens in order from the object side, and the image side of the positive lens of the cemented lens. A plastic aspherical layer is formed on the surface. Other lens configurations are the same as those in the first embodiment. The stop S is 1.00 ahead from the pole of the thirteenth surface (the 2a lens group 21).
(Table 3)
F = 1: 4.5
f = 28.95
W = 51.4
m = 0.000 / -0.025 / -0.216
fB = 60.50 / 61.28 / 67.94
Surface NO. Rd N d ν UN
1 83.312 2.30 1.77250 49.6
2 33.849 3.80---0.3843
3 44.953 2.00 1.77250 49.6
4 27.000 0.50 1.52972 42.7
5 * 21.452 11.90---0.8764
6 48.599 2.00 1.72916 54.7
7 34.871 19.17---1.1215
8 109.778 1.50 1.61800 63.4
9 27.741 9.00 1.77250 49.6
10 124.947 2.47---0.8232
11 54.458 11.00 1.49700 81.6
12 178.943 11.71-11.60-6.67--
13 53.307 10.68 1.68893 31.1
14 -46.946 0.71--
15 -82.581 4.00 1.49700 81.6
16 -21.199 1.30 1.88300 40.8
17 -191.146 10.63-9.95-8.23--
18 557.880 2.30 1.80518 25.4
19 32.749 8.03 1.59240 68.3
20 -28.700 0.30 1.52972 42.7
21 * -27.000 0.20--
22 -241.786 3.00 1.77250 49.6
23 397.698---
* Is a rotationally symmetric aspherical surface.
Aspheric data (Aspheric coefficient not shown is 0.00);
Surface NO K A4 A6
5 -0.10000 × 10 -0.30579 × 10 -6 0.27389 × 10 -8
21 0.00 0.81173 × 10 -5 -0.13710 × 10 -8
A8 A10
5 -0.63574 × 10 -11 0.14729 × 10 -14
21 0.35186 × 10 -10 -0.54724 × 10 -13
図７及び図８と表４は本発明による超広角レンズ系の実施例４を示している。図７はレンズ構成図、図８はその諸収差図、表４はその数値データである。第１ａレンズ群１１は、いずれも物体側に凸の２枚の負メニスカスレンズからなり、像側の負メニスカスレンズの像側の面に、プラスチックからなる非球面層が付着形成されている。第２ｂレンズ群２２は、物体側から順に、物体側の両凹負レンズと像側の両凸正レンズとの接合レンズからなり、この正レンズの像側の面にプラスチック非球面層が形成されている。第２ｃレンズ群２３は、像側凸の負メニスカスレンズからなる。この他のレンズ構成は実施例１と同様である。絞りＳは、第１１面（第２ａレンズ群２１）の極から前方1.00にある。
（表４）
F = 1: 4.0
f = 28.95
W = 51.6
m = 0.000 / -0.025 / -0.200
fB = 60.50 / 60.50 / 60.50
面NO. ｒ ｄ Ｎd ν UN
1 84.933 2.30 1.77250 49.6
2 29.000 5.85 - - -0.4988
3 34.466 2.00 1.72916 54.7
4 23.246 0.50 1.52972 42.7
5* 17.248 33.70 - - -1.0639
6 82.598 1.50 1.61800 63.4
7 31.651 9.00 1.72342 38.0
8 403.616 0.20 - - -0.4600
9 43.702 7.82 1.49700 81.6
10 112.117 7.10-6.60-4.99 - -
11 336.594 10.76 1.61293 37.0
12 -41.397 0.33 - -
13 -269.067 7.95 1.49700 81.6
14 -18.180 1.30 1.88300 40.8
15 -171.184 8.83-8.75-6.32 - -
16 -210.539 2.30 1.80518 25.4
17 70.012 7.49 1.59240 68.3
18 -25.683 0.30 1.52972 42.7
19* -24.737 1.00-1.58-5.62 - -
20 -100.000 3.00 1.77250 49.6
21 -131.199 - - -
*は回転対称非球面。
非球面データ（表示していない非球面係数は0.00である。）；
面NO Ｋ Ａ４ Ａ６
5 -0.10000×10 0.31359×10-5 -0.25441×10-8
19 0.00 0.65830×10-5 0.86817×10-8
Ａ８ Ａ１０
5 0.43328×10-11 -0.21277×10-13
19 0.25653×10-11 0.38030×10-13
7 and 8 and Table 4 show Example 4 of the super wide-angle lens system according to the present invention. FIG. 7 is a lens configuration diagram, FIG. 8 is a diagram showing aberrations thereof, and Table 4 is numerical data thereof. Each of the first-a lens group 11 is composed of two negative meniscus lenses convex on the object side, and an aspherical layer made of plastic is adhered to the image side surface of the negative meniscus lens on the image side. The second b lens group 22 is composed of a cemented lens of a biconcave negative lens on the object side and a biconvex positive lens on the image side in order from the object side, and a plastic aspheric layer is formed on the image side surface of the positive lens. ing. The second c lens group 23 is composed of a negative meniscus lens convex on the image side. Other lens configurations are the same as those in the first embodiment. The stop S is 1.00 ahead from the pole of the eleventh surface (the 2a lens group 21).
(Table 4)
F = 1: 4.0
f = 28.95
W = 51.6
m = 0.000 / -0.025 / -0.200
fB = 60.50 / 60.50 / 60.50
Surface NO. Rd N d ν UN
1 84.933 2.30 1.77250 49.6
2 29.000 5.85---0.4988
3 34.466 2.00 1.72916 54.7
4 23.246 0.50 1.52972 42.7
5 * 17.248 33.70---1.0639
6 82.598 1.50 1.61800 63.4
7 31.651 9.00 1.72342 38.0
8 403.616 0.20---0.4600
9 43.702 7.82 1.49700 81.6
10 112.117 7.10-6.60-4.99--
11 336.594 10.76 1.61293 37.0
12 -41.397 0.33--
13 -269.067 7.95 1.49700 81.6
14 -18.180 1.30 1.88300 40.8
15 -171.184 8.83-8.75-6.32--
16 -210.539 2.30 1.80518 25.4
17 70.012 7.49 1.59240 68.3
18 -25.683 0.30 1.52972 42.7
19 * -24.737 1.00-1.58-5.62--
20 -100.000 3.00 1.77250 49.6
21 -131.199---
* Is a rotationally symmetric aspherical surface.
Aspheric data (Aspheric coefficient not shown is 0.00);
Surface NO K A4 A6
5 -0.10000 × 10 0.31359 × 10 -5 -0.25441 × 10 -8
19 0.00 0.65830 × 10 -5 0.86817 × 10 -8
A8 A10
5 0.43328 × 10 -11 -0.21277 × 10 -13
19 0.25653 × 10 -11 0.38030 × 10 -13
図９及び図１０と表５は本発明による超広角レンズ系の実施例５を示している。図９はレンズ構成図、図１０はその諸収差図、表５はその数値データである。この実施例の基本的なレンズ構成は実施例４と同様である。絞りＳは、第１１面（第２ａレンズ群２１）の極から前方1.00にある。
（表５）
F = 1: 4.0
f = 28.95
W = 51.6
m = 0.000 / -0.025 / -0.197
fB = 60.50 / 60.50 / 60.50
面NO. ｒ ｄ Ｎd ν UN
1 83.409 2.30 1.77250 49.6
2 29.000 5.91 - - -0.4938
3 34.880 2.00 1.72916 54.7
4 23.306 0.50 1.52972 42.7
5* 17.385 33.75 - - -1.0585
6 86.501 1.50 1.61800 63.4
7 29.619 9.00 1.72342 38.0
8 603.799 0.20 - - -0.4217
9 44.698 6.93 1.49700 81.6
10 126.116 7.87-7.38-5.01 - -
11 506.868 10.97 1.60342 38.0
12 -38.772 0.24 - -
13 -299.427 6.58 1.49700 81.6
14 -18.002 1.30 1.88300 40.8
15 -202.070 8.64-8.61-7.45 - -
16 -194.484 2.30 1.80518 25.4
17 68.940 7.55 1.61800 63.4
18 -25.083 0.30 1.52972 42.7
19* -24.805 1.00-1.52-5.04 - -
20 -100.000 3.00 1.77250 49.6
21 -161.735 - - -
*は回転対称非球面。
非球面データ（表示していない非球面係数は0.00である。）；
面NO Ｋ Ａ４ Ａ６
5 -0.10000×10 0.30982×10-5 -0.23123×10-8
19 0.00 0.70851×10-5 0.76913×10-8
Ａ８ Ａ１０
5 0.39910×10-11 -0.21471×10-13
19 0.95733×10-11 0.24664×10-13
9 and 10 and Table 5 show Example 5 of the super wide-angle lens system according to the present invention. FIG. 9 is a lens configuration diagram, FIG. 10 is a diagram showing aberrations thereof, and Table 5 is numerical data thereof. The basic lens configuration of this embodiment is the same as that of Embodiment 4. The stop S is 1.00 ahead from the pole of the eleventh surface (the 2a lens group 21).
(Table 5)
F = 1: 4.0
f = 28.95
W = 51.6
m = 0.000 / -0.025 / -0.197
fB = 60.50 / 60.50 / 60.50
Surface NO. Rd N d ν UN
1 83.409 2.30 1.77250 49.6
2 29.000 5.91---0.4938
3 34.880 2.00 1.72916 54.7
4 23.306 0.50 1.52972 42.7
5 * 17.385 33.75---1.0585
6 86.501 1.50 1.61800 63.4
7 29.619 9.00 1.72342 38.0
8 603.799 0.20---0.4217
9 44.698 6.93 1.49700 81.6
10 126.116 7.87-7.38-5.01--
11 506.868 10.97 1.60342 38.0
12 -38.772 0.24--
13 -299.427 6.58 1.49700 81.6
14 -18.002 1.30 1.88300 40.8
15 -202.070 8.64-8.61-7.45--
16 -194.484 2.30 1.80518 25.4
17 68.940 7.55 1.61800 63.4
18 -25.083 0.30 1.52972 42.7
19 * -24.805 1.00-1.52-5.04--
20 -100.000 3.00 1.77250 49.6
21 -161.735---
* Is a rotationally symmetric aspherical surface.
Aspheric data (Aspheric coefficient not shown is 0.00);
Surface NO K A4 A6
5 -0.10000 × 10 0.30982 × 10 -5 -0.23123 × 10 -8
19 0.00 0.70851 × 10 -5 0.76913 × 10 -8
A8 A10
5 0.39910 × 10 -11 -0.21471 × 10 -13
19 0.95733 × 10 -11 0.24664 × 10 -13
図１１及び図１２と表６は本発明による超広角レンズ系の実施例６を示している。図１１はレンズ構成図、図１２はその諸収差図、表６はその数値データである。この実施例の第１ａレンズ群１１の構成は実施例４と同様である。第１ｂレンズ群１２は、物体側から順に、両凸正レンズ、像側に凸の負メニスカスレンズ、物体側の負レンズと像側の正レンズとの接合レンズ、及び正レンズからなる。この他のレンズ構成は実施例１と同様である。絞りＳは、第１５面（第２ａレンズ群２１）の極から前方0.80にある。
（表６）
F = 1: 4.5
f = 28.93
W = 51.4
m = 0.000 / -0.025 / -0.193
fB = 60.80 / 61.55 / 66.49
面NO. ｒ ｄ Ｎd ν UN
1 81.537 2.30 1.77250 49.6
2 29.000 9.17 - - -0.4871
3 51.205 2.00 1.72916 54.7
4 27.217 0.50 1.52972 42.7
5* 19.638 18.19 - - -1.1529
6 75.957 12.00 1.71736 29.5
7 -120.645 1.59 - - -0.2934
8 -58.877 2.00 1.80518 25.4
9 -98.984 6.00 - - -0.6108
10 -106.035 1.50 1.61800 63.4
11 20.178 9.00 1.77250 49.6
12 115.331 0.69 - - -0.9379
13 27.955 5.00 1.61800 63.4
14 80.312 6.20-6.05-5.00 - -
15 248.783 3.00 1.65446 33.6
16 -107.293 2.88 - -
17 81.676 5.00 1.49700 81.6
18 -15.906 1.30 1.88300 40.8
19 -82.209 11.45-10.86-6.80 - -
20 -69.122 2.30 1.80518 25.4
21 1064.628 6.33 1.58636 60.9
22* -23.972 - - -
*は回転対称非球面。
非球面データ（表示していない非球面係数は0.00である。）；
面NO Ｋ Ａ４ Ａ６
5 -0.10000×10 -0.43372×10-5 -0.42427×10-8
22 0.00 0.79201×10-5 0.13036×10-7
Ａ８ Ａ１０
5 0.22962×10-11 -0.90126×10-14
22 0.48207×10-11 0.37268×10-13
11 and 12 and Table 6 show Example 6 of the super wide-angle lens system according to the present invention. FIG. 11 is a lens configuration diagram, FIG. 12 is a diagram showing various aberrations, and Table 6 is numerical data thereof. The configuration of the first-a lens group 11 in this example is the same as that in Example 4. The 1b lens group 12 includes, in order from the object side, a biconvex positive lens, a negative meniscus lens convex on the image side, a cemented lens of a negative lens on the object side and a positive lens on the image side, and a positive lens. Other lens configurations are the same as those in the first embodiment. The stop S is 0.80 forward from the pole of the fifteenth surface (the 2a lens group 21).
(Table 6)
F = 1: 4.5
f = 28.93
W = 51.4
m = 0.000 / -0.025 / -0.193
fB = 60.80 / 61.55 / 66.49
Surface NO. Rd N d ν UN
1 81.537 2.30 1.77250 49.6
2 29.000 9.17---0.4871
3 51.205 2.00 1.72916 54.7
4 27.217 0.50 1.52972 42.7
5 * 19.638 18.19---1.1529
6 75.957 12.00 1.71736 29.5
7 -120.645 1.59---0.2934
8 -58.877 2.00 1.80518 25.4
9 -98.984 6.00---0.6108
10 -106.035 1.50 1.61800 63.4
11 20.178 9.00 1.77250 49.6
12 115.331 0.69---0.9379
13 27.955 5.00 1.61800 63.4
14 80.312 6.20-6.05-5.00--
15 248.783 3.00 1.65446 33.6
16 -107.293 2.88--
17 81.676 5.00 1.49700 81.6
18 -15.906 1.30 1.88300 40.8
19 -82.209 11.45-10.86-6.80--
20 -69.122 2.30 1.80518 25.4
21 1064.628 6.33 1.58636 60.9
22 * -23.972---
* Is a rotationally symmetric aspherical surface.
Aspheric data (Aspheric coefficient not shown is 0.00);
Surface NO K A4 A6
5 -0.10000 × 10 -0.43372 × 10 -5 -0.42427 × 10 -8
22 0.00 0.79201 × 10 -5 0.13036 × 10 -7
A8 A10
5 0.22962 × 10 -11 -0.90126 × 10 -14
22 0.48207 × 10 -11 0.37268 × 10 -13
図１３及び図１４と表７は本発明による超広角レンズ系の実施例７を示している。図１３はレンズ構成図、図１４はその諸収差図、表７はその数値データである。この実施例の基本的なレンズ構成は実施例６と同様である。絞りＳは、第１５面（第２ａレンズ群２１）の極から前方0.80にある。
（表７）
F = 1: 4.0
f = 28.93
W = 51.4
m = 0.000 / -0.025 / -0.192
fB = 60.82 / 61.56 / 66.43
面NO. ｒ ｄ Ｎd ν UN
1 86.955 2.30 1.77250 49.6
2 29.000 9.83 - - -0.5047
3 48.742 2.00 1.72916 54.7
4 26.700 0.50 1.52972 42.7
5* 18.866 16.17 - - -1.1981
6 69.256 10.69 1.71736 29.5
7 -111.457 1.82 - - -0.2817
8 -54.578 2.00 1.80518 25.4
9 -88.886 6.00 - - -0.5982
10 -110.010 1.50 1.61800 63.4
11 22.430 9.00 1.77250 49.6
12 147.512 0.45 - - -0.8579
13 29.189 5.00 1.59240 68.3
14 77.421 6.53-6.34-5.00 - -
15 287.908 3.00 1.65446 33.6
16 -114.797 4.52 - -
17 84.750 5.00 1.49700 81.6
18 -16.486 1.30 1.88300 40.8
19 -77.679 10.47-9.93-6.19 - -
20 -68.545 2.30 1.80518 25.4
21 -3328.539 6.58 1.58636 60.9
22* -23.520 - - -
*は回転対称非球面。
非球面データ（表示していない非球面係数は0.00である。）；
面NO Ｋ Ａ４ Ａ６
5 -0.10000×10 -0.49080×10-5 -0.50384×10-8
22 0.00 0.79201×10-5 0.13036×10-7
Ａ８ Ａ１０
5 0.20763×10-11 -0.10710×10-13
22 0.48207×10-11 0.37268×10-13
13 and 14 and Table 7 show Example 7 of the super wide-angle lens system according to the present invention. FIG. 13 is a lens configuration diagram, FIG. 14 is a diagram showing aberrations thereof, and Table 7 is numerical data thereof. The basic lens configuration of this embodiment is the same as that of Embodiment 6. The stop S is 0.80 forward from the pole of the fifteenth surface (the 2a lens group 21).
(Table 7)
F = 1: 4.0
f = 28.93
W = 51.4
m = 0.000 / -0.025 / -0.192
fB = 60.82 / 61.56 / 66.43
Surface NO. Rd N d ν UN
1 86.955 2.30 1.77250 49.6
2 29.000 9.83---0.5047
3 48.742 2.00 1.72916 54.7
4 26.700 0.50 1.52972 42.7
5 * 18.866 16.17---1.1981
6 69.256 10.69 1.71736 29.5
7 -111.457 1.82---0.2817
8 -54.578 2.00 1.80518 25.4
9 -88.886 6.00---0.5982
10 -110.010 1.50 1.61800 63.4
11 22.430 9.00 1.77250 49.6
12 147.512 0.45---0.8579
13 29.189 5.00 1.59240 68.3
14 77.421 6.53-6.34-5.00--
15 287.908 3.00 1.65446 33.6
16 -114.797 4.52--
17 84.750 5.00 1.49700 81.6
18 -16.486 1.30 1.88300 40.8
19 -77.679 10.47-9.93-6.19--
20 -68.545 2.30 1.80518 25.4
21 -3328.539 6.58 1.58636 60.9
22 * -23.520---
* Is a rotationally symmetric aspherical surface.
Aspheric data (Aspheric coefficient not shown is 0.00);
Surface NO K A4 A6
5 -0.10000 × 10 -0.49080 × 10 -5 -0.50384 × 10 -8
22 0.00 0.79201 × 10 -5 0.13036 × 10 -7
A8 A10
5 0.20763 × 10 -11 -0.10710 × 10 -13
22 0.48207 × 10 -11 0.37268 × 10 -13
各実施例の各条件式に対する値を表８に示す。
（表８）
実施例１ 実施例２ 実施例３ 実施例４ 実施例５
条件式（１） 0.214 0.180 0.402 0.031 0.083
条件式（２） 1.197 1.163 1.122 1.064 1.059
条件式（３） 1.139 1.229 1.439 1.532 1.536
条件式（４） 0.563 0.647 0.678 0.457 0.707
条件式（９） 81.6 81.6 81.6 81.6 81.6
実施例６ 実施例７
条件式（１） 0.031 0.083
条件式（２） 1.064 1.059
条件式（３） 1.532 1.536
条件式（４） 0.457 0.707
条件式（９） 81.6 81.6
Table 8 shows values for the conditional expressions in the respective examples.
(Table 8)
Example 1 Example 2 Example 3 Example 4 Example 5
Conditional expression (1) 0.214 0.180 0.402 0.031 0.083
Conditional expression (2) 1.197 1.163 1.122 1.064 1.059
Conditional expression (3) 1.139 1.229 1.439 1.532 1.536
Conditional expression (4) 0.563 0.647 0.678 0.457 0.707
Conditional expression (9) 81.6 81.6 81.6 81.6 81.6
Example 6 Example 7
Conditional expression (1) 0.031 0.083
Conditional expression (2) 1.064 1.059
Conditional expression (3) 1.532 1.536
Conditional expression (4) 0.457 0.707
Conditional expression (9) 81.6 81.6
表８から明らかなように、実施例１ないし７は条件式（１）〜（４）及び（９）を満足しており、また諸収差図から明らかなように諸収差も比較的よく補正されている。 Table 8 As is clear, Examples 1 to 7 are satisfied conditions (1) to (4) and (9), also aberrations As is apparent from the aberration diagrams also relatively well corrected ing.
Claims (7)
前群は、物体側から順に、該前群を構成する各レンズからの近軸軸上光線の射出傾角のうち負の最大値のところで分けられた負のパワーの第１ａレンズ群と、正のパワーの第１ｂレンズ群とを有し、次の条件式（１）及び（２）を満足すること、及び
後群は、物体側から順に、空気間隔が最大のところで分けられた可動の正の第２ａレンズ群と、可動の正の第２ｂレンズ群とを有し、フォーカシングのとき、この第２ａレンズ群と第２ｂレンズ群が次の条件式（４）を満足するように互いに独立して移動すること、
を特徴とする超広角レンズ系。
（１）ｆ／｜ｆＦ｜＜０．４５
（２）０．９＜ｆ／｜ｆ１ａ｜＜２．５
（４）０．２＜Ｘ２ａｎ／Ｘ２ｂｎ＜０．８
但し、
ｆ；全系の焦点距離、
ｆＦ；前群の焦点距離、
ｆ１ａ；第１ａレンズ群の焦点距離（ｆ１ａ＜０）、
Ｘ２ａｎ；無限遠物体から最短距離物体に向けてフォーカシングするときの第２ａレンズ群の移動量、
Ｘ２ｂｎ；無限遠物体から最短距離物体に向けてフォーカシングするときの第２ｂレンズ群の移動量。 In order from the object side, it consists of a front group of positive or negative power that does not move during focusing , a rear group of positive power that is a stop, and a focus lens group,
The front group includes, in order from the object side, a negative-power 1a lens group that is divided at the negative maximum value among the emission tilt angles of paraxial axial rays from the respective lenses constituting the front group; The first lens group of power and satisfying the following conditional expressions (1) and (2), and the rear group, in order from the object side, is a movable positive divided at the maximum air space A second positive lens unit 2a and a movable positive second lens unit 2. When focusing, the second lens unit 2b and the second lens unit 2b are independent from each other so that the following conditional expression (4) is satisfied. Moving,
Ultra-wide-angle lens system featuring
(1) f / | fF | <0.45
(2) 0.9 <f / | f1a | <2.5
(4) 0.2 <X2an / X2bn <0.8
However,
f: focal length of the entire system
fF: Focal length of the front group,
f1a: focal length of the 1a lens group (f1a <0),
X2an: the amount of movement of the 2a lens group when focusing from the object at infinity toward the object at the shortest distance,
X2bn: The amount of movement of the second lens group when focusing from an object at infinity toward the object at the shortest distance.
（３）０．９＜ｄ1a-1b／ｆ＜２．１
但し、
ｄ1a-1b；第１ａレンズ群の最も物体側の面から第１ｂレンズ群の最も物体側の面までの距離。 2. The super wide angle lens system according to claim 1, wherein the super wide angle lens system satisfies the following conditional expression (3).
(3) 0.9 <d 1a-1b /f<2.1
However,
d 1a-1b ; Distance from the most object side surface of the 1a lens group to the most object side surface of the 1b lens group.
（９）νRp＞８０
但し、
νRp；後群中に含まれる正レンズのアッベ数。 7. The super wide-angle lens system according to claim 1, wherein the rear group includes at least one positive lens, and at least one of the positive lenses has the following conditional expression: An ultra-wide-angle lens system that satisfies (9).
(9) ν Rp > 80
However,
ν Rp ; Abbe number of the positive lens included in the rear group.
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| JP4924003B2 (en) * | 2006-12-15 | 2012-04-25 | 株式会社ニコン | Wide-angle lens, imaging device, and wide-angle lens focusing method |
| JP5170616B2 (en) * | 2007-04-23 | 2013-03-27 | 株式会社ニコン | Wide angle lens, imaging device, and focusing method of wide angle lens |
| JP5374847B2 (en) * | 2007-08-30 | 2013-12-25 | 株式会社ニコン | Wide angle lens, imaging device, and imaging method of wide angle lens |
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| JP5402015B2 (en) | 2008-03-04 | 2014-01-29 | 株式会社ニコン | Rear focus optical system, imaging apparatus, and focusing method of rear focus optical system |
| JP5310352B2 (en) * | 2009-07-22 | 2013-10-09 | 株式会社リコー | Imaging lens, camera device, and portable information terminal device |
| JP5786537B2 (en) | 2010-08-19 | 2015-09-30 | リコーイメージング株式会社 | Retrofocus type wide-angle lens system and optical apparatus having the same |
| CN104101989A (en) * | 2014-08-04 | 2014-10-15 | 江苏卡罗卡国际动漫城有限公司 | Fish-eye lens for doublet lens |
| JP6392153B2 (en) | 2015-03-24 | 2018-09-19 | 富士フイルム株式会社 | Imaging lens and imaging apparatus |
| CN104777591B (en) * | 2015-04-08 | 2017-12-22 | 安徽长庚光学科技有限公司 | A kind of ultra-wide angle micro-lens |
| JP6401137B2 (en) * | 2015-09-28 | 2018-10-03 | 富士フイルム株式会社 | Imaging lens and imaging apparatus |
| DE102016117547A1 (en) * | 2016-09-18 | 2018-03-22 | Leica Camera Ag | Fixed focal length lens with constant length for autofocus applications |
| EP3343261B1 (en) | 2016-12-27 | 2022-05-18 | Canon Kabushiki Kaisha | Image pickup optical system, image pickup apparatus having the image pickup optical system, lens apparatus having the image pickup optical system, and image pickup system having the image pickup optical system |
| JP6983605B2 (en) * | 2017-09-29 | 2021-12-17 | キヤノン株式会社 | Single focus lens and image pickup device |
| JP6613277B2 (en) * | 2017-09-29 | 2019-11-27 | キヤノン株式会社 | Single focus lens and imaging device |
| JP2019159187A (en) * | 2018-03-15 | 2019-09-19 | 株式会社ニコン | Optical system, optical device, and method of manufacturing optical system |
| WO2021199923A1 (en) * | 2020-03-31 | 2021-10-07 | ソニーグループ株式会社 | Imaging lens and imaging device |
| CN115166952B (en) * | 2022-08-15 | 2023-09-26 | 苏州东方克洛托光电技术有限公司 | Uncooled long-wave infrared continuous zoom lens |
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| JP4177633B2 (en) * | 2002-10-15 | 2008-11-05 | 松下電器産業株式会社 | Wide-angle lens and video enlargement projection system, video projector, rear projector, and multivision system using the same |
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