Exposure control device
US4978981A · kind A · utility
46Cited by
8References
19Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Apr 25, 1989 |
| Grant date | Dec 18, 1990 |
| Priority date | — |
| Expiry date | Apr 25, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03B2217/005
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An exposure control device of a camera by which an appropriate camera-shake limit shutter speed T.sub.vf can be obtained in accordance with a focal length f of a photographing lens, and by which an arbitrary program can be set on the basis of the shutter speed T.sub.vf, in which T.sub.vf is obtained by an equation: EQU T.sub.vf =log.sub.2 f, EQU or EQU T.sub.vf =(log.sub.2 f).multidot..alpha.+.beta.; wherein .alpha.<1, and .alpha. and .beta. are constants which satisfy log.sub.2 f.sub.o =(log.sub.2 f.sub.o).multidot..alpha.+.beta. for a predetermined arbitrary focal length f.sub.o.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.