Photography – Exposure control circuit – Having plural photocells
Reexamination Certificate
2005-09-13
2005-09-13
Gray, David M. (Department: 2851)
Photography
Exposure control circuit
Having plural photocells
C396S100000
Reexamination Certificate
active
06944398
ABSTRACT:
A photometric device according to the present invention performs the steps of: performing photometry in a first area of an overall area where photometry can be performed; performing photometry in a plurality of second areas, each included in the first area; and when a difference greater than a predetermined value exists among the photometric results in the plurality of second areas, correcting the photometric result in the first area based on the photometric results in the plurality of second areas and determining a backlight state exist based on the corrected photometric result. Alternatively, the photometric device performs the steps of: setting a reference value for determining a backlight state exist based on the difference between the photometric result in the first area and a photometric result in a peripheral area around the first area or a photometric result in the overall area; and when a difference greater than a predetermined value exists among the photometric results in the plurality of second areas, correcting the reference value based on the photometric results in the plurality of second areas. In this manner, partial photometry and spot photometry can be performed at a lower luminance, and a backlight atate can be more accurately determined.
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Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Gray David M.
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