JP2000131606A5 - - Google Patents
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- JP2000131606A5 JP2000131606A5 JP1998301050A JP30105098A JP2000131606A5 JP 2000131606 A5 JP2000131606 A5 JP 2000131606A5 JP 1998301050 A JP1998301050 A JP 1998301050A JP 30105098 A JP30105098 A JP 30105098A JP 2000131606 A5 JP2000131606 A5 JP 2000131606A5
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- lens group
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Description
【特許請求の範囲】
【請求項１】 物体側から順に、全体として負のパワーを持つ第１レンズ群と、絞りと、全体として正のパワーを持つ第２レンズ群とからなり、前記第１レンズ群は、少なくとも１つの正レンズを含み全体として負のパワーを持つ第１−１レンズ群と、少なくとも１つの負レンズを含み全体として正のパワーを持つ第１−２レンズ群で構成され、以下の条件式を満足することを特徴とするバックフォーカスの長い広角レンズ。
（１） １．５＜Ｄ／ｆ＜５．０
（２） −１０．０＜ｆ12／ｆ11＜−２．８
ただし、Ｄ：無限遠物体にフォーカス時の第１レンズ群の最も像側の面と第２レンズ群の最も物体側の面との距離、ｆ：全系のｄ線の焦点距離、ｆ11：第１−１レンズ群のｄ線の焦点距離、ｆ12：第１−２レンズ群のｄ線の焦点距離、である。
【請求項２】 物体側から順に、全体として負のパワーを持つ第１レンズ群と、絞りと、全体として正のパワーを持つ第２レンズ群とからなり、前記第１レンズ群は、少なくとも１つの正レンズを含み全体として負のパワーを持つ第１−１レンズ群と、少なくとも１つの負レンズを含み全体として正のパワーを持つ第１−２レンズ群で構成され、無限遠から近距離にフォーカスを行う際、前記第１−２レンズ群を物体側から像側へ光軸方向に移動させることによりフォーカシングを行うことを特徴とするバックフォーカスの長い広角レンズ。
【請求項３】 以下の条件式を満足することを特徴とする請求項２記載のバックフォーカスの長い広角レンズ。
（２） −１０．０＜ｆ 12 ／ｆ 11 ＜−２．８
ただし、ｆ11：第１−１レンズ群のｄ線の焦点距離、ｆ12：第１−２レンズ群のｄ線の焦点距離、である。
【請求項４】 以下の条件式を満足することを特徴とする請求項３記載のバックフォーカスの長い広角レンズ。
（１） １．５＜Ｄ／ｆ＜５．０
ただし、Ｄ：無限遠物体にフォーカス時の第１レンズ群の最も像側の面と第２レンズ群の最も物体側の面との距離、ｆ：全系のｄ線の焦点距離、である。
【請求項５】 以下の条件式を満足することを特徴とする請求項１から４の何れか１項記載のバックフォーカスの長い広角レンズ。
（１２）０．６＜（Ｒ 2f ＋Ｒ 2b ）／（Ｒ 2f −Ｒ 2b ）＜５．０
ただし、Ｒ 2f ：第１−２群の最も物体側にある面の曲率半径、Ｒ 2b ：第１−２群の最も像側にある面の曲率半径、である。
[Claims]
1. The first lens group having a negative power as a whole, an aperture, and a second lens group having a positive power as a whole are composed of a first lens group having a negative power as a whole, and a second lens group having a positive power as a whole in order from the object side. It is composed of a 1-1 lens group that includes one positive lens and has negative power as a whole, and a 1-2 lens group that includes at least one negative lens and has positive power as a whole, and satisfies the following conditional expression. A wide-angle lens with a long back focus.
(1) 1.5 <D / f <5.0
(2) -10.0 <f12/ F11<-2.8
However, D: the distance between the most image-side surface of the first lens group and the most object-side surface of the second lens group when focusing on an infinite object, f: the focal length of the d-line of the entire system, f.11: Focal length of line d of the 1-1 lens group, f12: The focal length of the d-line of the 1-2 lens group.
2. The first lens group having a negative power as a whole, an aperture, and a second lens group having a positive power as a whole are composed of a first lens group having a negative power as a whole, and a second lens group having a positive power as a whole in order from the object side. It consists of a 1-1 lens group that includes one positive lens and has negative power as a whole, and a 1-2 lens group that includes at least one negative lens and has positive power as a whole, and focuses from infinity to a short distance. A wide-angle lens having a long back focus, characterized in that focusing is performed by moving the first and second lens groups from the object side to the image side in the optical axis direction.
3. The second aspect of claim 2, wherein the following conditional expression is satisfied.Wide-angle lens with long back focus.
(2) -10.0 <f 12 / F 11 <-2.8
However, f11: Focal length of line d of the 1-1 lens group, f12: The focal length of the d-line of the 1-2 lens group.
4. The wide-angle lens having a long back focus according to claim 3, wherein the wide-angle lens satisfies the following conditional expression.
(1) 1.5 <D / f <5.0
However, D: the distance between the most image-side surface of the first lens group and the most object-side surface of the second lens group when focusing on an infinite object, and f: the focal length of the d-line of the entire system.
5. The wide-angle lens having a long back focus according to any one of claims 1 to 4, wherein the wide-angle lens satisfies the following conditional expression.
(12) 0.6 <(R 2f + R 2b ) / (R 2f -R 2b ) <5.0
However, R 2f : Radius of curvature of the surface closest to the object in Group 1-2, R 2b : The radius of curvature of the surface closest to the image side of the 1-2 group.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP30105098A JP4339430B2 (en) | 1998-10-22 | 1998-10-22 | Wide-angle lens with long back focus |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP30105098A JP4339430B2 (en) | 1998-10-22 | 1998-10-22 | Wide-angle lens with long back focus |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| JP2000131606A JP2000131606A (en) | 2000-05-12 |
| JP2000131606A5 true JP2000131606A5 (en) | 2005-11-04 |
| JP4339430B2 JP4339430B2 (en) | 2009-10-07 |
Family
ID=17892266
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP30105098A Expired - Fee Related JP4339430B2 (en) | 1998-10-22 | 1998-10-22 | Wide-angle lens with long back focus |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP4339430B2 (en) |
Families Citing this family (16)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4678929B2 (en) * | 2000-10-10 | 2011-04-27 | 京セラ株式会社 | Retro focus lens |
| JP4757990B2 (en) * | 2000-10-25 | 2011-08-24 | リコー光学株式会社 | Projection lens |
| JP4349553B2 (en) | 2002-01-17 | 2009-10-21 | フジノン株式会社 | Fixed-focus wide-angle lens with long back focus |
| JP4405128B2 (en) | 2002-01-29 | 2010-01-27 | フジノン株式会社 | Imaging lens and imaging apparatus |
| JP4199550B2 (en) | 2003-01-23 | 2008-12-17 | Ｈｏｙａ株式会社 | Wide-angle lens system |
| EP1924874A4 (en) | 2005-08-11 | 2012-07-25 | Global Bionic Optics Pty Ltd | Optical lens systems |
| WO2007016718A1 (en) * | 2005-08-11 | 2007-02-15 | Global Bionic Optics Pty Ltd | Wide-angle, deep-field, close-focusing optical system |
| JP5259353B2 (en) * | 2008-11-20 | 2013-08-07 | 富士フイルム株式会社 | Projection lens and projection display device using the same |
| JP5682806B2 (en) * | 2009-03-17 | 2015-03-11 | 株式会社リコー | Imaging optical system, camera device, and portable information terminal device |
| JP5723071B2 (en) * | 2012-07-05 | 2015-05-27 | 富士フイルム株式会社 | Wide angle lens and imaging device |
| CN104395808B (en) | 2012-07-05 | 2017-09-29 | 富士胶片株式会社 | Imaging lens system and camera device |
| JP6539939B2 (en) * | 2013-08-14 | 2019-07-10 | 株式会社ニコン | Shooting lens and optical device |
| JP6546752B2 (en) * | 2015-02-27 | 2019-07-17 | 株式会社タムロン | Optical system and imaging device |
| WO2019207699A1 (en) * | 2018-04-26 | 2019-10-31 | オリンパス株式会社 | Objective optical system and imaging device using same |
| CN112639567B (en) | 2019-03-01 | 2022-09-27 | 奥林巴斯株式会社 | Wide-angle optical system and imaging device provided with same |
| JPWO2020178883A1 (en) * | 2019-03-01 | 2021-09-30 | オリンパス株式会社 | Wide-angle optical system and imaging equipment equipped with it |
-
1998
- 1998-10-22 JP JP30105098A patent/JP4339430B2/en not_active Expired - Fee Related
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