Provided are an image pickup apparatus and a method of controlling the image pickup apparatus, capable of quickly determining possibility of refocusing for bringing each of objects located at different view angle positions on a photographed image into focus. The image pickup apparatus includes an acquisition unit configured to acquire an image photographed by using an image pickup element having a pupil-division pixel area together with photographing information of an optical system at a time of photographing, an object detecting unit configured to calculate an object area of an object and to calculate an object distance corresponding to a depth distance to the object, and a refocusing possibility determining unit configured to determine possibility of refocusing for bringing the object into focus by calculating a refocusable view angle range and determining whether or not the object area is included in the refocusable view angle range through comparison.