Preflash pseudofocus/exposure control system
US4894678A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 1, 1989 |
| Grant date | Jan 16, 1990 |
| Priority date | — |
| Expiry date | May 1, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03B2215/0503
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An image of a subject in a scene formed by a fixed focus lens through a scanning aperture of an electronic flash camera, particularly that of a subject located closer to the lens than the near distance of its lens normal depth of field, has its clarity or sharpness substantially improved by firing the electronic flash during exposure at the smallest possible aperture for optimum subject image sharpness and overall scene exposure. The appropriate aperture to produce such an image is a function of ambient scene brightness and of the IR light from the electronic flash being reflected from a subject within the scene which are determined prior to and/or at the early stages of an exposure interval.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.