Patent ID: 7511740

Claim:
A digital camera comprising: an image pickup lens optical system; an iris for controlling a numerical aperture of a light path of said image pickup lens optical system; an image pickup device for detecting an image pickup subject formed by said image pickup lens optical system in an interlocking relationship with an operation of an electronic shutter and outputting an image pickup signal; gain control means having a controllable gain for amplifying the image pickup signal; luminance level detection means for detecting a luminance level based on the image pickup signal; first exposure amount arithmetic operation means for arithmetically operating a numerical aperture of said iris necessary to perform image pickup with a first appropriate exposure as a first numerical aperture based on the luminance level detected by said luminance level detection means; second exposure amount arithmetic operation means for arithmetically operating another numerical aperture of said iris necessary to perform image pickup with a second appropriate exposure as a second numerical aperture based on the luminance level detected by said luminance level detection means after the first numerical aperture is set to said iris; third exposure amount arithmetic operation means for arithmetically operating a correction amount for the shutter speed necessary to perform image pickup with appropriate exposure based on a difference between the first numerical aperture and the second numerical aperture; and shutter speed correction means for correcting the shutter speed of said electronic shutter of said image pickup device based on the correction amount for the shutter speed.