A camera system includes an interchangeable lens and a camera main body. The interchangeable lens includes a lens side storage unit that stores pupil related data according to an image height. The camera main body includes an image sensor including focus detection pixels, a main body side storage unit that stores correction data, and a correction unit corrects non-uniformity in illumination distribution of outputs of the focus detection pixels. The pupil related data is data regarding an F-number and an exit pupil position. The data regarding the F-number indicates a range of luminous flux to be applied to the focus detection pixels at a predetermined image height. The data regarding the exit pupil position relates to a position of intersection of a center of luminous flux applied to the focus detection pixels at a predetermined image height and an optical axis of the imaging optical system.