Preflash measurement technique
CA 2027515 C · Owner: Gray, Jeffrey T. · Inventors: Gray, Jeffrey T.; Gaewsky, John P.; Coltman, Judith Neely
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
An automatic exposure control system for an electronic flash camera incorporates an arrangement for measuring the reflectivity of a scene illuminated by the electronic flash prior to exposure in order to determine certain photographic scene characteristics for use in controlling a subsequent photographic exposure an arrangement that, substantially reduces the complexity and energy consumption of the electronic flash system while improving the ability of the exposure control system to accurately determine these scene characteristics. The arrangement includes the pre-exposure firing of the electronic flash to illuminate a scene with a pulse of light for a short fixed period of time. A …
Read the whole patent
Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.
Why it's free to use
- Filed October 12, 1990 and granted July 25, 2000. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended October 12, 2010.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by October 12, 2012.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
Timeline From CIPO dates
Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.