| 摘要 |
A light exposure control method for an image pickup apparatus is disclosed by which a good image which does not suffer from saturation nor from light source flickering can be obtained over an increased range of the illuminance of an image pickup object. While the shutter speed is set to 1/100 second so as to suppress a flicker component and the gain value is controlled within a positive range so as to keep photometry data substantially fixed, an image of the image pickup object is picked up. Then, if an image pickup object illuminance acquired based on the set gain value and shutter speed and the photometry data satisfies a condition determined in advance, then the gain is changed over to a negative gain. For example, if the photometry data cannot be kept fixed any more with the set gain value, then a negative gain is set. Consequently, the signal level after the gain adjustment drops, and as a result, the photometry data can be kept fixed again. Consequently, the dynamic range of the automatic gain control function for stabilizing the image luminance with respect to the image pickup object illuminance while the image is free from flickering can be expanded.
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