A non-transitory computer-readable storage medium stores a process for causing a computer to execute a method including the steps of acquiring optical transfer function information corresponding to an image pickup condition of a picked-up image (S102), generating a restoration image using correction optical transfer function information that is obtained by correcting the optical transfer function information using a correction value (S106-S108), and setting a settable range of the correction value based on an inverse characteristic of the optical transfer function information (S103, S104).