1. A camera which obtains a synthesized image whose exposure has been corrected by synthesizing a plurality of images obtained through successive image-taking, comprising: a detection unit which detects, with respect to a reference image, amounts of displacement on other images; a coordinate conversion unit which applies coordinate conversion to the other images based on the results of detection of the detection unit; and a synthesis unit which synthesizes the other images subjected to coordinate conversion and the reference image, wherein the detection unit divides the reference image into a first region including a focused region and a second region other than the first region, and detects the amounts of displacement based on a specific point in the second region of the reference image and specific points in respective regions corresponding to the second region of the other images.