Patent ID: 7551376

Claim:
A lens barrel provided in a body, comprising: a plurality of lens groups; a plurality of lens retention frames for retaining each of the plurality of lens groups to make a collapsed state in which at least a part of the plurality of lens groups is collapsed inside the body and a photographing state in which the part of the plurality of lens groups is moved to a subject side in an optical axis direction from the collapsed state; a movable lens cylinder for retaining the lens retention frames inside; a retractable lens retention frame configured to retain a retractable lens group; and a lens retention frame drive unit for driving the movable lens cylinder and the retractable lens retention frame, wherein, in the photographing state, all of the lens groups and the retractable lens group are disposed at a photographing position on a photographic optical axis, and in the collapsed state, the retractable lens group is retracted into a retracted position that lies out of the photographic optical axis and at the same time is outside a maximum outer radius of the movable lens cylinder of the other lens groups, the retractable lens retention frame including: an arm for moving the retractable lens group between the photographing position and the retracted position; an outer frame incorporating the arm; an inner frame movable in the optical axis direction with respect to the outer frame for holding the retractable lens group thereof; and an energizing member provided between the outer frame and the inner frame for energizing the inner frame to the optical axis direction with respect to the outer frame, wherein the inner frame is constructed to alternately take two positions of a forward position and a backward position, every time the inner frame is pushed by an external force applied in the optical axis direction, the forward position proceeding forward to the subject side in the optical axis direction with respect to the outer frame, the backward position proceeding backward to the image side in the optical axis direction with respect to the outer frame.