Camera having a zoom lens unit
US5157432A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 9, 1991 |
| Grant date | Oct 20, 1992 |
| Priority date | — |
| Expiry date | Jul 9, 2011 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B7/34
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An automatic focusing apparatus according to the present invention comprises a photo-taking lens system, in which a focus has to be adjusted every time the focal length is changed, including at least a first lens unit for changing the focal length by means of its movement along an optical axis of the photo-taking lens during the zooming operation and a second lens unit for adjusting the focus by means of its movement along the optical axis, and a controller for controlling the speed of the second lens unit during the zooming operation based on the focal length of the photo-taking lens system, the lapse of the time related with focus detection cycles, the reliability of the result of the focus detection and so on.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.