Exposure control device
US4123764A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 24, 1975 |
| Grant date | Oct 31, 1978 |
| Priority date | — |
| Expiry date | Dec 24, 1995 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03B7/087
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An automatic exposure control device is disclosed which is capable of aperture dominant and shutter speed dominant exposure control operation as well as manual exposure control operation. A logarithmic compression circuit including transducers develops voltages directly dependent upon the APEX indicating quantities Bv, Sv, Tv and Av. For automatic operation one of the voltages dependent upon Tv or Av is set into the circuit by manual control, and the other is calculated by the APEX indication formula Bv + Sv = Tv + Av, and applied as an output to the shutter control or aperture control mechanism. An indicator means is connected in the circuit to provide Tv or Av indications depending on the exposure control mode selected for the camera.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.