Image capturing apparatus, control method therefor, and program

A method of controlling an image capturing apparatus including an image capturing unit which has an image sensor for photoelectrically converting an object image, and generates an image signal on the basis of an output signal from the image sensor, a storage unit which stores foreign substance information including information on at least a position and size of a foreign substance adhering to an optical element arranged in front of the image sensor, a buffer unit which temporarily stores the image signal output from the image capturing unit, and a correction unit which corrects, based on the foreign substance information, an image signal corresponding to a shadow of the foreign substance among image signals output from the buffer unit and outputs a corrected image signal, the method comprising:

• a control step of controlling the buffer unit and the correction unit to change, in accordance with a free area of the buffer unit, an amount of the image signal corresponding to the shadow of the foreign substance that is to be corrected among image signals output from the image capturing unit.