Exposure control devices for photographic cameras
US4062023A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 6, 1976 |
| Grant date | Dec 6, 1977 |
| Priority date | — |
| Expiry date | Apr 6, 1996 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03B7/083
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An exposure control device for a photographic camera uses a conventional exchangeable lens and achieves a highly accurate exposure control commensurate with a pre-selected shutter speed by a light measuring device measuring scene light transmitted through the objective lens, diaphragm, and exchangeable lens. The device also permits exposure control commensurate with a pre-adjusted diaphragm aperture by storing the output from the light measuring device determined with the adjusted diaphragm aperture to control the shutter speed. However, when the device controls the exposure with a pre-selected shutter speed, the output from the light measuring device produced with a fully open diaphragm aperture is compared with the output produced commensurate with the pre-selected shutter speed to thereby control the diaphragm aperture in shifting from its open position to its closed position, and then stores the output from the light measuring device with the adjusted diaphragm aperture to thereby control the shutter speed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.