Telephoto lens system with three relatively shiftable lens groups
US4764000A · kind A · utility
5Cited by
4References
9Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | May 19, 1986 |
| Grant date | Aug 16, 1988 |
| Priority date | — |
| Expiry date | May 19, 2006 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B13/02
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A telephoto lens system is provided having a first lens group of a positive refractive power, a second lens group of a negative refractive power with a variable air space, and a third lens group of a positive refractive power with a variable air space. All of the lens groups are shiftable during a focusing operation with the second lens group air space increasing and the third lens group air space decreasing when focusing is effected from infinity to a short distance.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.