Patent ID: 7944501

Claim:
An image sensing apparatus comprising: a flash unit adapted to emit flashlight to a subject; an image sensing unit in which pixels containing photoelectric conversion devices are arranged in a plurality of lines; a drive unit configured to drive said image sensing unit so as to shift an exposure period in units of one line or a plurality of lines; and a control unit configured to determine, when a pre-flash firing for determining flash amount of the flash unit based on a signal output from a predetermined area of the image sensing unit is to be performed, if a shutter speed is less than a predetermined threshold value and: (a) if it is determined that the shutter speed is less than the threshold value, switch a read mode of the image sensing unit from a through-display read mode to a pre-flash read mode, and cause the flash unit to perform the pre-flash firing; and (b) if it is determined that the shutter speed is not less than the threshold value, cause the flash unit to perform the pre-flash firing without switching a read mode of the image sensing unit from the through-display read mode to the pre-flash read mode, wherein the through-display read mode is a read mode for performing through-display that displays continuous images output sequentially from the image sensing unit on a display unit, and the pre-flash read mode is a read mode in which a read period of the signal output from the predetermined area of the image sensing unit is shorter than that of the through-display read mode, and wherein the threshold value is equal to a sum of a read time from the predetermined area of the image sensing unit and a pre-flash time.