JPH0843732A - Wide converter lens - Google Patents
Wide converter lensInfo
- Publication number
- JPH0843732A JPH0843732A JP19495594A JP19495594A JPH0843732A JP H0843732 A JPH0843732 A JP H0843732A JP 19495594 A JP19495594 A JP 19495594A JP 19495594 A JP19495594 A JP 19495594A JP H0843732 A JPH0843732 A JP H0843732A
- Authority
- JP
- Japan
- Prior art keywords
- lens
- wide converter
- object side
- negative
- lenses
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Abstract
Description
【0001】[0001]
【産業上の利用分野】本発明は撮影レンズの前方に装着
して撮影系全体の焦点距離を短い方に変位させるワイド
コンバーターレンズに関し、特に写真用カメラやビデオ
カメラ、そして電子カメラ等に用いられるズームレンズ
や単一焦点距離レンズ等の撮影レンズに装着したときに
好適なレンズ系全体の小型軽量化を図り、かつ高い光学
性能を有したワイドコンバーターレンズに関するもので
ある。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wide converter lens which is mounted in front of a photographing lens and displaces the focal length of the entire photographing system to the shorter side, and is particularly used for a photographic camera, a video camera, an electronic camera and the like. The present invention relates to a wide converter lens which is suitable for mounting on a photographing lens such as a zoom lens or a single focal length lens and which is suitable for downsizing and weight reduction of the entire lens system and has high optical performance.
【0002】[0002]
【従来の技術】従来より撮影レンズの前方に装着し、全
系の焦点面を一定位置に維持した状態で撮影系全体の焦
点距離を短い方に変化させるフロント方式のワイドコン
バーターレンズが種々と提案されている。2. Description of the Related Art Conventionally, various front wide converter lenses have been proposed which are mounted in front of a taking lens and change the focal length of the entire taking system to a shorter one while keeping the focal plane of the entire system at a fixed position. Has been done.
【0003】このワイドコンバーターレンズは多くの場
合、負の屈折力の前群と正の屈折力の後群の2つのレン
ズ群を両レンズ群の焦点距離の和だけ主点間隔を隔てて
配置し、全体としてアフォーカル系を構成している。In many cases, this wide converter lens has two lens groups, a front lens group having a negative refractive power and a rear lens group having a positive refractive power, which are arranged at a principal point distance by a sum of focal lengths of both lens groups. , As a whole, constitutes an afocal system.
【0004】この為最も簡単なレンズ系としては特開平
4−70616号公報で提案されているように負と正の
屈折力の2つのレンズより構成することができる。しか
しながら撮影レンズに装着したとき所定の光学性能を得
るには収差補正上、各レンズ群を複数のレンズより構成
することが必要となってくる。Therefore, the simplest lens system can be composed of two lenses having negative and positive refracting powers, as proposed in Japanese Patent Laid-Open No. 4-70616. However, in order to obtain a predetermined optical performance when the lens unit is mounted on a taking lens, it is necessary to configure each lens group with a plurality of lenses in terms of aberration correction.
【0005】例えば特開昭59−204817号公報で
は物体側より順に負の屈折力の第1群と正の屈折力の第
2群より成り全体として5つのレンズよりアフォーカル
系を構成し、アフォーカル倍率0.7倍程度のワイドコ
ンバーターレンズを提案している。For example, in Japanese Unexamined Patent Publication No. 59-204817, an afocal system is composed of five lenses as a whole, which is composed of a first group having a negative refractive power and a second group having a positive refractive power in order from the object side. We have proposed a wide converter lens with a focal magnification of about 0.7.
【0006】[0006]
【発明が解決しようとする課題】一般に撮影レンズの前
方に装着するフロント方式のワイドコンバーターレンズ
はワイドコンバーターレンズを装着しても全系のFナン
バーや焦点面を不変とすることができるという長所を有
している。Generally, the front type wide converter lens mounted in front of the taking lens has an advantage that the F number and the focal plane of the entire system can be kept unchanged even if the wide converter lens is mounted. Have
【0007】しかしながらフロント方式のワイドコンバ
ーターレンズは撮影レンズの前方に装着する為にレンズ
系全体が大型化し、かつ高重量となる傾向がある。特に
撮影レンズ系に装着したとき所定の光学性能を得たい場
合、あるいは小型化のために各レンズ群の屈折力を大き
くした場合に各レンズ群を複数のレンズより構成する
と、最も物体側のレンズの位置が撮影レンズの入射瞳か
ら遠くなるために、レンズ系の大型化は避けられなかっ
た。However, since the front wide converter lens is mounted in front of the taking lens, the entire lens system tends to be large and heavy. In particular, if each lens group is composed of multiple lenses when it is desired to obtain a predetermined optical performance when it is attached to a photographing lens system, or when the refractive power of each lens group is increased for downsizing, the lens closest to the object side Since the position of is far from the entrance pupil of the taking lens, it is inevitable that the lens system becomes large.
【0008】一方、レンズ系の構成枚数を少なくしてワ
イドコンバーターレンズの小型化を図る場合には諸収差
の中でも特に歪曲収差と像面湾曲の低減が最後まで課題
となる。歪曲収差に関しては特開平4−116511号
公報や特開平4−260609号公報に見られるよう
に、負の屈折力の前群を2枚の凹レンズで構成すること
で屈折力を分散することで低減を図っている。しかしな
がら前記公報ではコンバーターのアフォーカル倍率が
0.65倍から0.8倍となっており小型化を保ったま
ま更にアフォーカル倍率を小さくした場合の歪曲収差と
像面湾曲の低減については開示されていない。On the other hand, in order to downsize the wide converter lens by reducing the number of constituent lens systems, among the various aberrations, reduction of distortion and field curvature remains a problem until the end. Distortion aberration is reduced by dispersing the refracting power by configuring the front group of negative refracting power with two concave lenses, as seen in JP-A-4-116511 and JP-A-4-260609. I am trying to However, in the above publication, the afocal magnification of the converter is changed from 0.65 times to 0.8 times, and it is disclosed about reduction of distortion and field curvature when the afocal magnification is further reduced while keeping downsizing. Not not.
【0009】本発明はレンズ構成を適切に設定すること
により、撮影レンズの物体側に装着し、全系の焦点距離
と短い方に変位させることのできる全体として3枚の所
定形状のレンズより成るアフォーカル倍率が小さく、又
撮影レンズの物体側に装着したときの全系の諸収差、特
に歪曲収差と像面湾曲を効果的に補正した高い光学性能
が得られるワイドコンバーターレンズの提供を目的とす
る。According to the present invention, by appropriately setting the lens configuration, the lens is mounted on the object side of the taking lens and is composed of three lenses having a predetermined shape as a whole which can be displaced to the focal length of the entire system and to the shorter one. The purpose of the invention is to provide a wide converter lens that has a small afocal magnification and that effectively corrects various aberrations of the entire system when mounted on the object side of the taking lens, especially distortion and field curvature. To do.
【0010】[0010]
【課題を解決するための手段】本発明のワイドコンバー
ターレンズは、撮影レンズの前方に装着し、全系の焦点
距離を短い方に変位させるワイドコンバーターレンズに
おいて、該ワイドコンバーターレンズは物体側より順に
物体側へ凸面を向けたメニスカス状の負の第1レンズ、
像面側に強い負の屈折面を向けた負の第2レンズ、物体
側に比べ像面側に強い正の屈折面を有した両レンズ面が
凸面の正の第3レンズの3つのレンズを有し、該第3レ
ンズの材質の屈折率が該第1,第2レンズの材質の屈折
率に比べて小さいことを特徴としている。The wide converter lens of the present invention is mounted on the front side of a photographing lens and displaces the focal length of the entire system to the shorter side. The wide converter lens is arranged in order from the object side. A negative meniscus first lens whose convex surface faces the object side,
A negative second lens having a strong negative refracting surface facing the image side, and a third lens having a positive positive refracting surface on the image side as compared to the object side. It is characterized in that the refractive index of the material of the third lens is smaller than the refractive index of the material of the first and second lenses.
【0011】[0011]
【実施例】図1は本発明のワイドコンバーターレンズを
撮影レンズ(マスターレンズ)の前方に装着したときの
実施例1のレンズ断面図である。図2〜図4は本発明の
ワイドコンバーターレンズの数値実施例1〜3のレンズ
断面図、図5は図1の撮影レンズのレンズ断面図であ
る。図中Cはワイドコンバーターレンズであり、全体と
してアフォーカル系より成っている。EXAMPLE 1 FIG. 1 is a lens sectional view of Example 1 in which the wide converter lens of the present invention is mounted in front of a taking lens (master lens). 2 to 4 are lens cross-sectional views of Numerical Examples 1 to 3 of the wide converter lens of the present invention, and FIG. 5 is a lens cross-sectional view of the taking lens of FIG. In the figure, C is a wide converter lens, which is composed of an afocal system as a whole.
【0012】本実施例のワイドコンバーターレンズCは
物体側に凸面を向けたメニスカス状の負の第1レンズC
1、像面側に強い負の屈折面を向けた負の第2レンズC
2、そして物体側に比べて像面側に強い正の屈折面を向
けた両レンズ面が凸面の正の第3レンズC3より成って
いる。第1レンズC1と第2レンズC2で負の屈折力の
前群CAを、第3レンズC3で正の屈折力の後群CBを
構成している。The wide converter lens C of this embodiment is a negative meniscus first lens C having a convex surface facing the object side.
1. Negative second lens C with a strong negative refracting surface facing the image side
2. The third lens C3 has a positive lens having a positive refractive surface facing the image side more strongly than the object side, and having a convex positive surface. The first lens C1 and the second lens C2 constitute a front group CA having a negative refractive power, and the third lens C3 constitutes a rear group CB having a positive refractive power.
【0013】Mは撮影レンズ(マスターレンズ)であ
り、単一の焦点距離のレンズ又はズームレンズより成っ
ている。4は像面でありワイドコンバーターレンズCの
装着の有無によらず一定位置にある。5は光軸である。Reference numeral M denotes a photographing lens (master lens), which is composed of a lens having a single focal length or a zoom lens. An image surface 4 is at a fixed position regardless of whether the wide converter lens C is attached or not. 5 is an optical axis.
【0014】一般に撮影レンズはそれ自身で撮影を行う
為に撮影レンズで単独で良好に収差補正がなされてい
る。この為ワイドコンバーターレンズを装着したときに
全体的に良好なる光学性能を得るにはワイドコンバータ
ーレンズ単独で良好なる収差補正を達成しておく必要が
ある。In general, since the photographing lens itself performs photographing, the aberration of the photographing lens is favorably corrected by itself. Therefore, in order to obtain a good optical performance as a whole when the wide converter lens is attached, it is necessary to achieve good aberration correction by the wide converter lens alone.
【0015】本実施例において前群CAの合成焦点距離
をf1、後群CBの焦点距離をf2、前群CAと後群C
Bとの主点間隔をe′とすると全系がアフォーカル系で
ある為に e′=f1+f2 ‥‥‥(1) となっている。又ワイドコンバーターレンズCのアフォ
ーカル倍率αは α=|f1/f2| ‥‥‥(2) であり、一般には|f1|<f2でありα<1である。In the present embodiment, the combined focal length of the front group CA is f1, the focal length of the rear group CB is f2, the front group CA and the rear group C.
When the principal point distance from B is e ′, e ′ = f1 + f2 (1) because the entire system is an afocal system. The afocal magnification α of the wide converter lens C is α = | f1 / f2 | (2), and generally | f1 | <f2 and α <1.
【0016】これよりワイドコンバーターレンズCを焦
点距離Fの撮影レンズMに装着したときの全系の焦点距
離Faは Fa=α・F と短い方に変位する。As a result, when the wide converter lens C is attached to the taking lens M having the focal length F, the focal length Fa of the entire system is displaced to the shorter one as Fa = α · F.
【0017】ここでアフォーカル倍率αを小さくして撮
影レンズに装着したときの全系の広画角化を図る場合、
(2)式より後群CBの焦点距離f2の絶対値を大きく
する必要がある。すると(1)式から前群と後群の主点
間隔e′が長くなり、レンズ系全体が大型化してくる。In order to widen the angle of view of the entire system when the afocal magnification α is reduced and the lens is attached to the taking lens,
From the equation (2), it is necessary to increase the absolute value of the focal length f2 of the rear lens group CB. Then, from the formula (1), the principal point distance e ′ between the front group and the rear group becomes long, and the entire lens system becomes large.
【0018】そこで主点間隔e′を小さくする為には前
群と後群の焦点距離f1,f2の絶対値を(1),
(2)式を満足させつつ小さくする必要がある。即ち全
体的に前群と後群の屈折力を強くする必要がある。一般
にはレンズ群の屈折力を強めると収差が多く発生し、良
好なる収差補正が難しくなってくる。特に、アフォーカ
ル倍率αを小さくして広画角化を図る場合には広角レン
ズ特有のタル型の歪曲収差が多く発生してくる。Therefore, in order to reduce the principal point interval e ', the absolute values of the focal lengths f1 and f2 of the front lens group and the rear lens group are (1),
It is necessary to reduce the size while satisfying the expression (2). That is, it is necessary to strengthen the refractive powers of the front group and the rear group as a whole. Generally, when the refracting power of the lens group is strengthened, a large amount of aberration occurs, and it becomes difficult to correct aberrations satisfactorily. In particular, when the afocal magnification α is reduced to achieve a wide angle of view, a lot of Tal-type distortion aberration peculiar to a wide-angle lens occurs.
【0019】そこで本実施例では前群CAと後群CBの
屈折力を強くし、主点間隔e′を小さく設定してもワイ
ドコンバーターレンズCを構成する3つのレンズのレン
ズ形状を前述の如く構成することにより、撮影レンズM
に装着したとき全系の焦点距離を所定量短い方に変位さ
せると共に球面収差等の軸上収差と軸外収差を良好に補
正している。Therefore, in this embodiment, even if the refractive powers of the front lens group CA and the rear lens group CB are increased and the principal point spacing e'is set small, the lens shapes of the three lenses forming the wide converter lens C are as described above. By configuring, the taking lens M
When the lens is mounted on, the focal length of the entire system is displaced to a shorter side by a predetermined amount, and on-axis aberrations such as spherical aberration and off-axis aberrations are well corrected.
【0020】図1に示すように歪曲収差はその光線の通
り方から考えると主に負の前群CAで発生してくる。As shown in FIG. 1, the distortion aberration mainly occurs in the negative front group CA when considering the path of the light rays.
【0021】そこで本実施例では前群CAを2枚の負レ
ンズC1,C2で構成して負の屈折力を分散し、これに
より歪曲収差の発生を少なくしている。又正の第3レン
ズC3の材質の屈折率が負の第1,第2レンズの材質の
屈折率に比べて低くなるようにしてペッツバール和を小
さくし、広画角化した際にやはり問題となる像面湾曲を
効果的に低減している。また、正の第3レンズC3を物
体側に比べて像面側に強い正の屈折面を向けた両レンズ
面が凸面のレンズ形状より構成して諸収差を良好に補正
すると共に前述したようにペッツバール和を小さくする
為に第3レンズC3として材質の屈折率が第1,第2レ
ンズに比べて小さいものを用いている。Therefore, in this embodiment, the front group CA is composed of two negative lenses C1 and C2 to disperse the negative refracting power, thereby reducing the occurrence of distortion. Further, the Petzval sum is reduced by making the refractive index of the material of the positive third lens C3 lower than that of the material of the negative first and second lenses, and this also causes a problem when the angle of view is widened. The effective field curvature is effectively reduced. In addition, the positive third lens C3 is configured to have a convex lens shape with both positive and negative refracting surfaces facing the image side as compared to the object side, so that various aberrations can be satisfactorily corrected and as described above. In order to reduce the Petzval sum, a material whose refractive index is smaller than that of the first and second lenses is used as the third lens C3.
【0022】特に本実施例では第3レンズC3の像面側
のレンズ面の屈折力を強くし、且つマスターレンズMの
絞りに対して凸面を向けるようにして、これにより糸巻
き型の歪曲収差を発生させて強い負の屈折力の前群CA
で発生するタル型の歪曲収差を良好に補正している。In particular, in this embodiment, the refractive power of the image-side lens surface of the third lens C3 is strengthened, and the convex surface is directed toward the diaphragm of the master lens M, so that pincushion distortion aberration is caused. Front group CA with strong negative refractive power generated
The Tal-type distortion that occurs in 1 is corrected well.
【0023】尚本発明において第3レンズC3の物体側
と像面側のレンズ面の曲率半径を各々R5,R6とした
とき −0.6<(R6+R5)/(R6−R5)<0 ‥‥‥(1) なる条件を満足させるのが良い。In the present invention, when the radiuses of curvature of the object-side and image-side lens surfaces of the third lens C3 are R5 and R6, respectively, -0.6 <(R6 + R5) / (R6-R5) <0. It is good to satisfy the condition (1).
【0024】条件式(1)は第3レンズC3のレンズ形
状を適切に設定し、主に歪曲収差を良好に補正する為の
ものである。条件式(1)の下限値を越えて第3レンズ
C3のレンズ形状が平凸レンズに近付くと後群CBに要
求される正の屈折力を比較的低い屈折率の材質で得る為
に第3レンズC3の像側のレンズ面の曲率がきつくなり
過ぎてしまい、軸外での収差、特に糸巻き型の歪曲と非
点収差が多く発生してくるので良くない。Conditional expression (1) is for properly setting the lens shape of the third lens C3 and mainly for favorably correcting distortion. When the lens shape of the third lens C3 approaches the plano-convex lens beyond the lower limit of conditional expression (1), the third lens C3 is provided in order to obtain the positive refractive power required for the rear group CB with a material having a relatively low refractive index. The curvature of the image side lens surface of C3 becomes too tight, and off-axis aberrations, particularly pincushion type distortion and astigmatism, occur in large numbers, which is not preferable.
【0025】逆に条件式(1)の上限値を越えて像側の
レンズ面の曲率がゆるくなり過ぎると後群CBで発生す
る糸巻き型の歪曲収差が少なくなり、前群CAで発生す
るタル型の歪曲収差をキャンセルできず、全体としてタ
ル型の歪曲収差が大きく発生してくるので良くない。On the contrary, if the curvature of the lens surface on the image side becomes too loose beyond the upper limit of the conditional expression (1), pincushion distortion aberration generated in the rear lens group CB decreases and the tal lens generated in the front lens group CA. Type distortion aberration cannot be canceled, and a large amount of tal type distortion aberration is generated as a whole, which is not good.
【0026】尚本発明において条件式(1)の上限値を
「−0.17」程度にすると、更に諸収差を良好に補正
することができるので好ましい。In the present invention, it is preferable to set the upper limit of conditional expression (1) to about "-0.17" because it is possible to satisfactorily correct various aberrations.
【0027】次に本発明のワイドコンバーターレンズ及
びそれを装着する撮影レンズ(マスターレンズ)の数値
実施例を示す。数値実施例においてRiは物体側より順
に第i番目の曲率半径、Diは物体側より順に第i番目
のレンズ厚及び空気間隔、Niとνiは各々物体側より
順に第i番目のレンズのガラスの屈折率とアッベ数であ
る。尚マスターレンズにおいてR14,R15はフェー
スプレート等のガラス材である。Next, numerical examples of the wide converter lens of the present invention and the photographing lens (master lens) to which the wide converter lens is attached will be shown. In the numerical example, Ri is the i-th radius of curvature in order from the object side, Di is the i-th lens thickness and air gap in order from the object side, and Ni and νi are the glass of the i-th lens in order from the object side, respectively. The refractive index and the Abbe number. In the master lens, R14 and R15 are glass materials such as a face plate.
【0028】*ワイドコンバーターレンズ 〈数値実施例1〉 f=0.56 FNo=1:2.5 2ω= 78.5° R 1= 2.179 D 1= 0.171 N 1=1.83400 ν 1= 37.2 R 2= 1.253 D 2= 0.764 R 3= -9.846 D 3= 0.128 N 2=1.77250 ν 2= 49.6 R 4= 2.234 D 4= 0.547 R 5= 3.803 D 5= 0.663 N 3=1.70154 ν 3= 41.2 R 6= -2.694 α=0.56 f1=−9.00 f2=16.07 e′=7.07 〈数値実施例2〉 f=0.56 FNo=1:2.5 2ω= 78.5° R 1= 2.440 D 1= 0.171 N 1=1.69680 ν 1= 55.5 R 2= 1.203 D 2= 0.719 R 3=125.562 D 3= 0.114 N 2=1.77250 ν 2= 49.6 R 4= 1.804 D 4= 0.455 R 5= 2.398 D 5= 0.857 N 3=1.53172 ν 3= 48.9 R 6= -2.178 α=0.56 f1=−9.00 f2=16.07 e′=7.07 〈数値実施例3〉 f=0.49 FNo=1:2.5 2ω= 86.0° R 1= 2.172 D 1= 0.171 N 1=1.69680 ν 1= 55.5 R 2= 1.241 D 2= 0.885 R 3= 20.256 D 3= 0.114 N 2=1.77250 ν 2= 49.6 R 4= 1.739 D 4= 0.792 R 5= 6.312 D 5= 0.857 N 3=1.53172 ν 3= 48.9 R 6= -1.958 α=0.49 f1=−10.00 f2=20.41 e′=10.41 *撮影レンズ 〈数値実施例1〉 f=1 FNo=1:2.5 2ω= 49.1° R 1= 2.253 D 1= 0.285 N 1=1.58144 ν 1= 40.8 R 2=-33.536 D 2= 0.028 R 3= 3.295 D 3= 0.100 N 2=1.77250 ν 2= 49.6 R 4= 0.626 D 4= 1.142 R 5= -3.369 D 5= 0.714 N 3=1.60342 ν 3= 38.0 R 6= -1.120 D 6= 0.214 R 7=(絞り) D 7= 0.357 R 8= 0.936 D 8= 0.285 N 4=1.72000 ν 4= 50.3 R 9=-39.450 D 9= 0.021 R10= -2.917 D10= 0.285 N 5=1.80518 ν 5= 25.4 R11= 0.842 D11= 0.185 R12= 2.154 D12= 0.314 N 6=1.69680 ν 6= 55.5 R13= -1.513 D13= 0.342 R14= ∞ D14= 0.657 N 7=1.51633 ν 7= 64.2 R15= ∞ 各数値実施例の数値条件式に対応する数値を表1に示
す。* Wide Converter Lens <Numerical Example 1> f = 0.56 FNo = 1: 2.5 2ω = 78.5 ° R 1 = 2.179 D 1 = 0.171 N 1 = 1.83400 ν 1 = 37.2 R 2 = 1.253 D 2 = 0.764 R 3 = -9.846 D 3 = 0.128 N 2 = 1.77250 ν 2 = 49.6 R 4 = 2.234 D 4 = 0.547 R 5 = 3.803 D 5 = 0.663 N 3 = 1.70154 ν 3 = 41.2 R 6 = -2.694 α = 0.56 f1 = −9.00 f2 = 16.07 e ′ = 7.07 <Numerical Example 2> f = 0.56 FNo = 1: 2.5 2ω = 78.5 ° R 1 = 2.440 D 1 = 0.171 N 1 = 1.69680 ν 1 = 55.5 R 2 = 1.203 D 2 = 0.719 R 3 = 125.562 D 3 = 0.114 N 2 = 1.77250 ν 2 = 49.6 R 4 = 1.804 D 4 = 0.455 R 5 = 2.398 D 5 = 0.857 N 3 = 1.53172 ν 3 = 48.9 R 6 = -2.178 α = 0.56 f1 = -9.00 f2 = 16.07 e ′ = 7.07 <Numerical Example 3> f = 0.49 FNo = 1: 2.5 2ω = 86.0 ° R 1 = 2.172 D 1 = 0.171 N 1 = 1.69680 ν 1 = 55.5 R 2 = 1.241 D 2 = 0.885 R 3 = 20.256 D 3 = 0.114 N 2 = 1.77 250 ν 2 = 49.6 R 4 = 1.739 D 4 = 0.792 R 5 = 6.312 D 5 = 0.857 N 3 = 1.53172 ν 3 = 48.9 R 6 = -1.958 α = 0.49 f1 = -10.00 f2 = 20.41 e '= 10.41 * Shooting lens <Numerical Example 1> f = 1 FNo = 1: 2.5 2ω = 49.1 ° R 1 = 2.253 D 1 = 0.285 N 1 = 1.58144 ν 1 = 40.8 R 2 = -33.536 D 2 = 0.028 R 3 = 3.295 D 3 = 0.100 N 2 = 1.77250 ν 2 = 49.6 R 4 = 0.626 D 4 = 1.142 R 5 = -3.369 D 5 = 0.714 N 3 = 1.60342 ν 3 = 38.0 R 6 = -1.120 D 6 = 0.214 R 7 = (Aperture) D 7 = 0.357 R 8 = 0.936 D 8 = 0.285 N 4 = 1.72000 ν 4 = 50.3 R 9 = -39.450 D 9 = 0.021 R10 =- 2.917 D10 = 0.285 N 5 = 1.80518 ν 5 = 25.4 R11 = 0.842 D11 = 0.185 R12 = 2.154 D12 = 0.314 N 6 = 1.69680 ν 6 = 55.5 R13 = -1.513 D13 = 0.342 R14 = ∞ D14 = 0.657 N 7 = 1.51633 ν 7 = 64.2 R15 = ∞ Table 1 shows the numerical values corresponding to the numerical conditional expressions of each numerical example.
【0029】[0029]
【表1】 [Table 1]
【0030】[0030]
【発明の効果】以上述べたように、本発明によれば撮影
レンズの前方に装着して撮影系全体の焦点距離を短い方
へ変位させる際、前述の条件を満足する3つのレンズよ
り構成することによりアフォーカル倍率が0.5倍程度
と広角化を図りつつ、レンズ系の小型化と撮影レンズ系
に装着したときの全系の光学性能、特に歪曲収差と像面
湾曲を良好に維持したワイドコンバーターレンズを達成
することができる。As described above, according to the present invention, when the lens is mounted in front of the photographing lens and the focal length of the entire photographing system is displaced to the shorter side, it is composed of three lenses satisfying the above-mentioned conditions. As a result, the afocal magnification was widened to about 0.5 times, while the lens system was downsized and the optical performance of the entire system when mounted on the taking lens system, particularly distortion and field curvature, were favorably maintained. Wide converter lens can be achieved.
【図1】本発明のワイドコンバーターレンズを撮影レン
ズの前方に装着したときのレンズ断面図FIG. 1 is a lens sectional view when a wide converter lens of the present invention is mounted in front of a taking lens.
【図2】本発明のワイドコンバーターレンズの数値実施
例1のレンズ断面図FIG. 2 is a lens cross-sectional view of Numerical Example 1 of a wide converter lens according to the present invention.
【図3】本発明のワイドコンバーターレンズの数値実施
例2のレンズ断面図FIG. 3 is a lens cross-sectional view of a numerical example 2 of the wide converter lens of the present invention.
【図4】本発明のワイドコンバーターレンズの数値実施
例3のレンズ断面図FIG. 4 is a lens sectional view of a numerical example 3 of the wide converter lens of the present invention.
【図5】図1の撮影レンズのレンズ断面図5 is a lens cross-sectional view of the taking lens of FIG.
【図6】本発明の数値実施例1のワイドコンバーターレ
ンズを撮影レンズの前方に装着したときの諸収差図FIG. 6 is a diagram of various aberrations when the wide converter lens according to Numerical Example 1 of the present invention is mounted in front of the taking lens.
【図7】本発明の数値実施例2のワイドコンバーターレ
ンズを撮影レンズの前方に装着したときの諸収差図FIG. 7 is a diagram showing various aberrations when the wide converter lens of Numerical Example 2 of the present invention is mounted in front of the taking lens.
【図8】本発明の数値実施例3のワイドコンバーターレ
ンズを撮影レンズの前方に装着したときの諸収差図FIG. 8 is a diagram showing various aberrations when the wide converter lens of Numerical Example 3 of the present invention is mounted in front of the taking lens.
【図9】図1の撮影レンズの諸収差図9 is a diagram of various aberrations of the taking lens of FIG.
C ワイドコンバーターレンズ CA 前群 CB 後群 M 撮影レンズ d d線 g g線 ΔM メリディオナル像面 ΔS サジタル像面 C Wide converter lens CA Front group CB Rear group M Photographic lens d d line g g line ΔM meridional image surface ΔS sagittal image surface
Claims (2)
距離を短い方に変位させるワイドコンバーターレンズに
おいて、該ワイドコンバーターレンズは物体側より順に
物体側へ凸面を向けたメニスカス状の負の第1レンズ、
像面側に強い負の屈折面を向けた負の第2レンズ、物体
側に比べ像面側に強い正の屈折面を有した両レンズ面が
凸面の正の第3レンズの3つのレンズを有し、該第3レ
ンズの材質の屈折率が該第1,第2レンズの材質の屈折
率に比べて小さいことを特徴とするワイドコンバーター
レンズ。1. A wide converter lens which is mounted in front of a taking lens and which displaces the focal length of the entire system to the shorter side, wherein the wide converter lens is a meniscus negative lens whose convex surface faces in order from the object side to the object side. First lens,
A negative second lens having a strong negative refracting surface facing the image side, and a third lens having a positive positive refracting surface on the image side as compared to the object side. A wide converter lens having the refractive index of the material of the third lens is smaller than that of the material of the first and second lenses.
径をRiとしたとき −0.6<(R6+R5)/(R6−R5)<0 なる条件を満足することを特徴とする請求項1のワイド
コンバーターレンズ。2. When the radius of curvature of the i-th lens surface from the object side is Ri, the condition of −0.6 <(R6 + R5) / (R6-R5) <0 is satisfied. 1 wide converter lens.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP19495594A JPH0843732A (en) | 1994-07-27 | 1994-07-27 | Wide converter lens |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP19495594A JPH0843732A (en) | 1994-07-27 | 1994-07-27 | Wide converter lens |
Publications (1)
Publication Number | Publication Date |
---|---|
JPH0843732A true JPH0843732A (en) | 1996-02-16 |
Family
ID=16333114
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP19495594A Pending JPH0843732A (en) | 1994-07-27 | 1994-07-27 | Wide converter lens |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPH0843732A (en) |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2006119346A (en) * | 2004-10-21 | 2006-05-11 | Canon Inc | Wide converter lens and imaging device having the same |
JP2006235167A (en) * | 2005-02-24 | 2006-09-07 | Seiko Epson Corp | Fisheye conversion lens |
JP2006276220A (en) * | 2005-03-28 | 2006-10-12 | Nikon Corp | Wide converter |
US20110085245A1 (en) * | 2009-10-13 | 2011-04-14 | Samsung Electronics Co., Ltd. | Wide converter lens |
JP2014048590A (en) * | 2012-09-03 | 2014-03-17 | Ricoh Co Ltd | Wide converter lens |
-
1994
- 1994-07-27 JP JP19495594A patent/JPH0843732A/en active Pending
Cited By (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2006119346A (en) * | 2004-10-21 | 2006-05-11 | Canon Inc | Wide converter lens and imaging device having the same |
JP4659429B2 (en) * | 2004-10-21 | 2011-03-30 | キヤノン株式会社 | Wide converter lens and imaging device having the same |
JP2006235167A (en) * | 2005-02-24 | 2006-09-07 | Seiko Epson Corp | Fisheye conversion lens |
JP4687143B2 (en) * | 2005-02-24 | 2011-05-25 | セイコーエプソン株式会社 | Fisheye conversion lens |
JP2006276220A (en) * | 2005-03-28 | 2006-10-12 | Nikon Corp | Wide converter |
JP4725156B2 (en) * | 2005-03-28 | 2011-07-13 | 株式会社ニコン | Wide converter |
US20110085245A1 (en) * | 2009-10-13 | 2011-04-14 | Samsung Electronics Co., Ltd. | Wide converter lens |
CN102043232A (en) * | 2009-10-13 | 2011-05-04 | 三星电子株式会社 | Wide converter lens |
US8743468B2 (en) * | 2009-10-13 | 2014-06-03 | Samsung Electronics Co., Ltd. | Wide converter lens |
JP2014048590A (en) * | 2012-09-03 | 2014-03-17 | Ricoh Co Ltd | Wide converter lens |
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