Zoom lens having focusing subunit in second lens unit and optical apparatus equipped with the same
US6147810A · kind A · utility
16Cited by
10References
24Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | May 27, 1998 |
| Grant date | Nov 14, 2000 |
| Priority date | — |
| Expiry date | May 27, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B15/17
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A small-sized zoom lens in which the displacement of the focusing lens unit does not increase to an excessive degree during focusing, the zoom lens including a first lens unit of positive refractive power; a second lens unit of negative refractive power; and a subsequent lens unit of positive refractive power in that order from the object side, wherein focusing is effected by a subunit 2b of negative refractive power constituting a part of the second lens unit and wherein, assuming that the magnification of the subunit 2b at the wide-angle end is .beta.2bw, the following condition is satisfied: EQU 0<.beta.2bw<1.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.