Camera zoom lens automatic magnification apparatus
US4878080A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 15, 1988 |
| Grant date | Oct 31, 1989 |
| Priority date | — |
| Expiry date | Aug 15, 2008 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B7/282
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A camera zoom lens automatic magnification apparatus for automatically changing the focal length of a zoom lens wherein distances to at least three points on a subject--at the center, to the left and to the right--in the angle of view are measured by a range finding device and a zoom lens driving device for changing the focal length of the zoom lens is controlled by a control device according to the output of the range finding device. The control device consists of a first decision device to decide which point is the nearest by comparing the distances to each point measured by the range finding device, a second decision device which, based on the lens focal length corresponding to the closest distance as found by the first decision device and on the depth of field for that focal length, checks if there is any other point's distance that is within the depth of field for that focal length, a third decision device which determines the zoom ratio according to a predetermined program using the result of the second decision device, and an output device which drives the zoom lens driving device according to the third decision device.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.