The image pickup system includes a camera and an interchangeable lens having an image-taking optical system. The camera includes an image sensor to photoelectrically convert an object image formed by the image-taking optical system and to be moved in an optical axis direction, and a camera controller configured to control movement of the image sensor such that focus variation caused due to variation of magnification of the interchangeable lens is reduced. The camera controller is configured to acquire image sensor moving data corresponding to the interchangeable lens attached to the camera, and controls the movement of the image sensor by using the image sensor moving data.