Patent ID: 7573661

Claim:
A lens device comprising: a plurality of focus lens groups; a plurality of movement lens frames respectively holding the plurality of focus lens groups; a plurality of cam pins arranged respectively in the plurality of movement lens frames; a fixed lens barrel supporting the plurality of movement lens frames so that the movement lens frames are movable in a direction of the optical axis; and a cam cylinder supported rotatably by the fixed lens barrel and at the same time having a plurality of cam grooves engaged respectively with the plurality of cam pins, wherein the plurality of movement lens frames are disposed such that a part of one movement lens frame overlaps with another movement lens frame in a direction of the optical axis, and are combined in a nested manner, and the plurality of cam pins are disposed at a different position from each other in a circumferential direction, and at the same time the cam pin of the one movement lens frame and the cam pin of another said movement lens frame are disposed at substantially the same position in a direction of the optical axis when the movement lens frames are brought into closest proximity to each other, wherein the plurality of movement lens frames are each provided with a guide member protruding from the outer circumferential surface of the movement lens frame and at the same time extending outwards in a direction of the optical axis, a straight groove in a direction of the optical axis is formed in the guide member, and a guide pin engaged with the straight groove is arranged in the fixed lens barrel, and when the plurality of movement lens frames are combined in a nested manner, the guide member of one lens frame lies between the guide members of the other lens frames and thus the guide members are disposed in an alternate manner.