Camera having a zoom lens unit
US4935763A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 26, 1989 |
| Grant date | Jun 19, 1990 |
| Priority date | — |
| Expiry date | Jun 26, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B7/282
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
When a variator lens is driven to effect zooming, focal length information of a zoom lens unit, a zooming direction and a defocus amount are detector. Integration in CCD for focus detection is regulated in a short time during zooming and a cycle of focus detection is set to a predetermined period. A moving speed of a compensator lens is controlled based on detected information. A moving range of the variator lens is divided into zones and a basic moving speed of the compensator lens is set for each zone. When the variator lens is driven and information obtained by focus detection or a zooming condition corresponds to a specified condition, the compensator lens is moved at a basic speed corresponding to the zone where the variator lens exists or at a moving speed of the compensator lens applied till then. Focus detection areas automatically changed dependent on a situation of an object are forbidden to be changed during zooming. In addition, a focus detection are indicating mark displayed in a finder of the camera is fixed and unchanged during zooming irrespective of actual change of the focus detection area.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.