A camera system includes a camera body having an in-body motor; an
interchangeable lens having an in-lens motor, the interchangeable lens
being detachable from the camera body; a focusing mechanism for moving a
focusing lens group provided in the interchangeable lens in an optical
axis direction thereof; a rotational force transmission device which
transmits a rotational force of the in-body motor to the focusing
mechanism to perform an AF operation in a state where the interchangeable
lens is attached to the camera body; an auto-focusing mechanism for
driving the focusing mechanism to perform an AF operation by the in-lens
motor, independently from the in-body motor; and a one-way clutch which
allows transmission of a rotational force of the in-body motor to the
in-lens motor while preventing a rotational force of the in-lens motor
from being transmitted to the in-body motor.