Exposure control devices for photographic cameras
US3950765A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 9, 1974 |
| Grant date | Apr 13, 1976 |
| Priority date | — |
| Expiry date | Jul 9, 1994 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03B7/083
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
In an exposure control device for a photographic camera a shutter speed control signal generating circuit measures scene light transmitted through an objective lens and a diaphragm for automatically controlling the shutter speed commensurate to the measured light output. A control output signal is generated in response to a manually selectable shutter speed. A diaphragm control device controls the diaphragm aperture according to the difference in the light measuring output and shutter speed output signal. The light measuring and shutter speed output signals are selectively connectable to a shutter speed control device for exposure control. A portion of the automatic shutter speed control signal is added to the manually selected shutter speed control signal so that diaphragm aperture control is effected according to the difference between the combined signal and the automatic shutter speed control signal. Control of the diaphragm and shutter speed as well as programmed exposure control of the shutter speed and diaphragm aperture commensurate with the brightness of an object are effected.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.