Program exposure calculating apparatus
US4945380A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 14, 1988 |
| Grant date | Jul 31, 1990 |
| Priority date | — |
| Expiry date | Nov 14, 2008 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03B2217/005
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A program exposure calculating apparatus compares exposure value a reference exposure value provided based on a restricting exposure time and a full open aperture value, and when the exposure value is smaller than the reference exposure value, the apparatus outputs a full open aperture value and information of the exposure time which is appropriate for the full open aperture value. When the exposure value is greater than the reference exposure value, informations of the exposure time and an appropriate aperture value determined from the exposure value, the restricting exposure time, the full open aperture value and from a program constant are outputted, for controlling the aperture and the shutter. The restricting exposure time is adapted such that it becomes shorter as a focal length becomes longer in response to information of the focal length, and the program constant is set such that the slope of the program line becomes steeper as the focal length becomes shorter, in response to the information of the focal length.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.