Image pickup apparatus and recording medium

A recording medium storing a computer program contained in an image pickup apparatus comprising an image pickup unit for obtaining an image, the image pickup unit including an image pickup element and an image pickup optical system which includes an aperture stop and forms the image on the image pickup element, the computer program including:

• a synthesis instruction step of providing an instruction to form a multiple exposure image by making registration of a plurality of images and synthesizing the plurality of images into one image;
• an aperture value control step of controlling setting of an aperture value of an aperture stop when the instruction to form the multiple exposure image is provided in the synthesis instruction step;
• and
• an image processing step of forming the multiple exposure image by synthesizing, into one image, a plurality of images obtained by the image pickup unit with the aperture value set in the aperture value control step.