A camera system has a camera with a photosensitive member that records
optical images; and a lens apparatus removably mounted on the camera and
forming an optical image with an image taking optical system including a
focus lens. Focus control of the focus lens is changed in accordance the
photosensitive member. A control circuit controls a lens driving unit and
sets a driving pattern in accordance with information stored in a
photosensitive member information storage circuit, and controls the lens
driving unit based on focus adjustment state detected by a focus
detection unit. An in-focus state can be achieved with focus accuracy
suited for a photosensitive member in a combination of different cameras
provided with different photosensitive members and interchangeable lenses
common to these cameras.