Long focal length macrolens system
US5909319A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 30, 1997 |
| Grant date | Jun 1, 1999 |
| Priority date | — |
| Expiry date | Sep 30, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B7/04
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A high-performance, long-focal length macrolens system is provided which is easy-to-operate and is capable of photographing an object at an infinitely far distance and an object at a close distance without changing the overall length of the macrolens system. The system is configured in order from the object side, having: PA1 a first lens group G1, which includes a negative lens and has a positive overall refractive power, PA1 a second lens group G2, which includes a compound lens and has a negative overall refractive power, PA1 a third lens group G3, which includes a compound lens and has a negative overall refractive power, and PA1 a fourth lens group G4, which has a positive refractive power, and the system fulfills at least three preselected conditions.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.