Camera system, camera body, and lens unit

A camera system, comprising:

• a lens unit including at least one lens unit operation portion and configured to change the magnification of an optical image electrically;
• a mount configured to support removably the lens unit;
• and
• a camera body including a zoom operation portion for changing the magnification of an optical image, wherein
• at least one function other than zooming function is assigned to the zoom operation portion of the camera body, and either one of the non-electrical zoom lens unit or the camera body is controlled, if a non-electrical zoom lens unit is mounted to the camera body.

A camera body that is used in a camera system for capturing an image of a subject, comprising:

• an imaging unit configured to image a subject;
• a mount configured to support removably the lens unit;
• a control unit configured to control the lens unit mounted to the mount;
• and
• a zoom operation portion configured to change the magnification of an optical image of the lens unit electrically.