1. An image processing apparatus for processing an image constructed from a plurality of plane images, each of which has distance information indicating a shooting distance, comprising: an obtaining unit configured to obtain the distance information from a target plane image including at least one subject; a calculating unit configured to calculate an area change amount of the target plane image in a case where a transformation process corresponding to an enlargement or reduction is performed on the target plane image; a determiner configured to determine a depth change amount of the transformed plane image based on the distance information and the area change amount; and a corrector configured to perform a correction process for the image in accordance with a correction strength determined as proportional to the depth change amount.