JPS5699313A - Behind stop lens - Google Patents
Behind stop lensInfo
- Publication number
- JPS5699313A JPS5699313A JP138480A JP138480A JPS5699313A JP S5699313 A JPS5699313 A JP S5699313A JP 138480 A JP138480 A JP 138480A JP 138480 A JP138480 A JP 138480A JP S5699313 A JPS5699313 A JP S5699313A
- Authority
- JP
- Japan
- Prior art keywords
- group
- lens
- constitution
- refractive indexes
- difficulties
- 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.)
- Granted
Links
- 239000011521 glass Substances 0.000 abstract 3
- 238000004519 manufacturing process Methods 0.000 abstract 2
- 230000005499 meniscus Effects 0.000 abstract 2
- 230000007423 decrease Effects 0.000 abstract 1
- 230000003247 decreasing effect Effects 0.000 abstract 1
- 230000000694 effects Effects 0.000 abstract 1
- 238000010348 incorporation Methods 0.000 abstract 1
- 239000000463 material Substances 0.000 abstract 1
Landscapes
- Lenses (AREA)
Abstract
PURPOSE: To provide a lens of a low cost which decreases difficulties in fabrication, by setting the refractive indexes of the glasses constituting the 3rd group lens and 4th group lens of a lens system of 4-group constitution at prescribed values.
CONSTITUTION: The 1st group is a meniscus positive lens, the 2nd group is biconcave negative lens, the 3rd group is a meniscus positive lens directing its concave side to the object side and the 4th group is a lens group consisting of a biconvex positive lens. When the refractive indexes of the glasses constituting the 3rd group and 4th group are defined as n3, n4, respectively, they are so set as to satisfy the conditions of the formula I, II. By the incorporation of the 4-group lens constitution, the sharing of powers is achieved, by which the effect of errors is decreased and the difficulties in fabrication are reduced; further, the use of glass materials of lower refractive indexes hence lower costs is made possible. The combined focal length is about 1.09W1.1 and the lens of wider angles of ≥60° covering angle is obtained.
COPYRIGHT: (C)1981,JPO&Japio
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP138480A JPS5699313A (en) | 1980-01-11 | 1980-01-11 | Behind stop lens |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP138480A JPS5699313A (en) | 1980-01-11 | 1980-01-11 | Behind stop lens |
Publications (2)
Publication Number | Publication Date |
---|---|
JPS5699313A true JPS5699313A (en) | 1981-08-10 |
JPH0262846B2 JPH0262846B2 (en) | 1990-12-26 |
Family
ID=11499980
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP138480A Granted JPS5699313A (en) | 1980-01-11 | 1980-01-11 | Behind stop lens |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPS5699313A (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4983026A (en) * | 1986-12-27 | 1991-01-08 | Minolta Camera Kabushiki Kaisha | Focal length changeable lens system |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS509468U (en) * | 1973-05-30 | 1975-01-30 | ||
JPS5238218A (en) * | 1975-08-13 | 1977-03-24 | Bell & Howell Co | Optical system for macrofilm |
-
1980
- 1980-01-11 JP JP138480A patent/JPS5699313A/en active Granted
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS509468U (en) * | 1973-05-30 | 1975-01-30 | ||
JPS5238218A (en) * | 1975-08-13 | 1977-03-24 | Bell & Howell Co | Optical system for macrofilm |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4983026A (en) * | 1986-12-27 | 1991-01-08 | Minolta Camera Kabushiki Kaisha | Focal length changeable lens system |
US5086355A (en) * | 1986-12-27 | 1992-02-04 | Minolta Camera Kabushiki Kaisha | Focal length changeable lens system |
Also Published As
Publication number | Publication date |
---|---|
JPH0262846B2 (en) | 1990-12-26 |
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