Patent ID: 8040616

Claim:
A lens barrel comprising: a barrel body; a diaphragm pivotally held in the barrel body; a diaphragm operating member that changes the diameter of the diaphragm, the diaphragm operating member having an engagement piece protruding therefrom; an operation arm that can pivot in the barrel body and fits in the diaphragm operating member, the operation arm, when pivoted, changing the diameter of the diaphragm via the diaphragm operating member; and a light-blocking plate that prevents unwanted light from entering the barrel body and has a passage cutout through which the operation arm passes and an engagement portion that the engaging piece protruding from the diaphragm operating member engages so as to prevent the light-blocking plate from separating from the diaphragm operating member during operational movement thereof along an optical axis direction, the light-blocking plate, along with the diaphragm operating member, pivotally supported, wherein the passage cutout has an opening having a width that is substantially the same as the width of the operation arm, and wherein the light-blocking plate has a disc shape with a predetermined outer diameter with the passage cutout of the light-blocking plate being formed on a periphery thereof, and the light-blocking plate further has a circular opening in a center thereof which is configured to allow a portion of a lens holding frame to pass.