Zoom lens having two lens groups
US6185050A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 26, 1999 |
| Grant date | Feb 6, 2001 |
| Priority date | — |
| Expiry date | Mar 26, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B15/142
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A zoom lens includes: a first lens group having positive refracting power; and a second lens group provided on an image side of the first lens group, having negative refracting power. The zoom lens has a variable power ratio of not less than 2.5 and a field angle of not less than 70.degree. at a wide angle end, and a magnification of the zoom lens is changed by changing a distance between the first lens group and the second lens group, and further the following conditions are satisfied, EQU 1.25.ltoreq.Tw/Tt.ltoreq.1.8 EQU 0.6.ltoreq.fFc/fw.ltoreq.0.9 where Tw represents a telephoto ratio at a wide angle end of the zoom lens, Tt represents a telephoto ratio at a telephoto end of the zoom lens, fw represents a focal length of the zoom lens at the wide angle end, and fFc represents a focal length of the first lens group.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.