A retractable lens system includes optical elements of a photographing
optical system, and are positioned on a common optical axis when in a
ready-to-photograph state. When the retractable lens system changes from
the ready-to-photograph state to a retracted state, a removable optical
element of the optical elements is moved to a removed position, and the
removable optical element and an element of the remaining optical
elements are moved rearward. The element of the remaining elements
includes a linearly movable element which moves in the common optical
axis direction without changing a distance between the linearly movable
element and the removable optical element in the ready-to-photograph
state. A part of the removable optical element and a part of the linearly
movable element are positioned on a common plane perpendicular to the
common optical axis when the retractable lens system changes from the
ready-to-photograph state to the retracted state.