Variable proportional fill flash
US4317620A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 17, 1980 |
| Grant date | Mar 2, 1982 |
| Priority date | — |
| Expiry date | Jan 17, 2000 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03B15/05
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A photographic exposure and flash fire control system initially measures ambient scene light and subsequently utilizes the results of that measurement to control the amount of artificial illumination provided during the exposure interval. The initial measurement of ambient scene light below a first select level provides for a maximum flash output while conversely the initial measurement of ambient scene light above a second select level greater than the first select level provides for minimum flash output. The initial measurement of ambient scene light between the aforementioned first and second levels provides for a flash output which progressively varies between the aforementioned minimum and maximum outputs in inverse corresponding relation with respect to the progressive variation of measured ambient scene light between its first and second select levels.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.