Patent ID: 8081236

Claim:
A camera system, which performs an exposure amount control operation in combination with gradation conversion processing for an image signal acquired from an image pickup device, comprising: a pre-shooting control unit which performs a first control operation so as to perform pre-shooting multiple times with different exposure amounts prior to a real shooting; a conversion property calculation unit which calculates first conversion properties with respect to signals that correspond to image signals acquired in the pre-shooting, which are to be used in the gradation conversion processing; an exposure control unit which determines an exposure amount used in the real shooting based upon the signals that correspond to the image signals acquired in the pre-shooting, exposure amounts used in the pre-shooting, and the first conversion properties, the exposure control unit comprising: a dark-region ineffective pixel estimation unit which estimates a relation between a number of ineffective pixels in a dark region and the exposure amount based upon the signal that corresponds to the image signal obtained in the real shooting, the exposure amounts used in the pre-shooting, and the first conversion properties; a bright-region ineffective pixel estimation unit which estimates the relation between a number of ineffective pixels in a bright region and the exposure amount based upon the signal that corresponds to the image signal obtained in the real shooting, the exposure amounts used in the pre-shooting, and the first conversion properties; and an exposure amount calculation unit which calculates the exposure amount for the real shooting based upon the relation between the number of the ineffective pixels in the dark region and the exposure amount and the relation between the number of the ineffective pixels in the bright region and the exposure amount; a real shooting control unit which performs a second control operation so as to perform the real shooting based upon the determined exposure amount; and a gradation conversion unit which calculates second conversion properties with respect to a signal that corresponds to an image signal obtained in the real shooting, which are to be used in the gradation conversion processing, and performs the gradation conversion processing.