Patent ID: 7158322

Claim:
A lens device comprising: at least two lens groups, each of the at least two lens groups comprising: a lens; and a lens frame that supports the lens, the lens frame having a plurality of cam followers disposed on an outer periphery of the lens frame at substantially uniform pitches; a rotary cylinder having a plurality of cam grooves in an outer periphery of the rotary cylinder, wherein the cam followers are inserted into the cam grooves so that when the rotary cylinder rotates around an optical axis, the cam grooves press the cam followers to move the at least two lens groups in a direction of the optical axis; and a translatory-moving guide that regulates a movement of the cam followers in the direction of the optical axis, wherein the at least two lens groups comprise a first lens group and a second lens group, each of the first and second lens groups having a retaining guide section on a surface facing another of the first and second lens groups, wherein the retaining guide section of one of the first and second lens groups retains and guides the other of the first and second lens groups so that the other of the first and second lens groups can rotate around the optical axis in the rotary cylinder.