1. An image processing apparatus comprising: a depth map acquiring unit configured to acquire a depth map that records information indicating a depth distance corresponding to each point on a photographed image; an in-focus position acquiring unit configured to acquire an in-focus position on the photographed image; a reference distance determining unit configured to acquire a depth distance corresponding to the in-focus position from the depth map and sets the acquired depth distance as a reference distance; and an image processing unit configured to perform image processing on the photographed image by using the depth map and the reference distance.