Patent ID: 7916409

Claim:
A lens mechanism, comprising: a) a plurality of lens groups each having at least one lens; b) a plurality of lens retaining frames which retain a corresponding one of the plurality of lens groups, the plurality of lens groups being located on a photographing optical axis in a photographable state; c) a telescopic cylinder containing therein the plurality of lens groups and the plurality of lens retaining frames in the photographable state; d) a lens retaining frame driving device configured to drive at least one of the lens retaining frames; at least one of the plurality of lens groups being collapsed to store the plurality of lens groups in a collapsed state and the at least one of the plurality of lens groups being expanded in the photographable state, the plurality of lens retaining frames including a retractable lens retaining frame configured to retain at least another one of the plurality of lens groups, configured to retract the at least another one of the plurality of lens groups from the photographing optical axis to a retracted position out of the telescopic cylinder in the collapsed state and configured to move the at least another one of the plurality of lens groups from the retracted position to a position on the photographing optical axis in the photographable state; e) a moving member which moves in a direction along the photographing optical axis; the at least another one of the plurality of lens groups being moved between the retracted position and a position on the photographing optical axis in accordance with the movement of the moving member in the direction along the photographing optical axis; and f) a position detector configured to detect a change in a position of the moving member.