Patent ID: 7031603

Claim:
A lens barrel comprising: at least one optical element configured to be guided along an optical axis; a rotatable ring rotatable about a rotational axis extending in a direction of said optical axis, said optical element moving along said optical axis by a rotation of said rotatable ring; an outer annular member, which is non-rotatable about said rotational axis, supporting said rotatable ring inside said outer annular member, and including at least one circumferential groove located on an inner peripheral surface of said outer annular member which faces said rotatable ring; an advancing/retracting mechanism, provided between an outer peripheral surface of said rotatable ring and said inner peripheral surface of said outer annular member, configured to move said rotatable ring along said optical axis between front and rear limits for movement of said rotatable ring in said optical axis direction relative to said outer annular member when said rotatable ring is rotated; at least one rotational projection located on said outer peripheral surface of said rotatable ring, wherein said at least one rotational projection is engaged in said at least one circumferential groove such that said rotatable ring is rotatable at an axial fixed position without moving along said optical axis when said rotatable ring is moved to one of said front and rear limits by said advancing/retracting mechanism; and a stopper insertable into and removable from said at least one circumferential groove at an intermediate point between opposite ends of said at least one circumferential groove, wherein said stopper limits the range of rotation of said rotatable ring about said rotational axis relative to said outer annular member by engaging said rotational projection in a state where said stopper is positioned in said circumferential groove, and wherein said stopper stops preventing said range of rotation of said rotatable ring in a state where said stopper is positioned outside said circumferential groove.