Patent ID: 8693861

Claim:
A lens barrel that supports a lens, comprising: a first frame; a second frame configured to be supported rotatably by the first frame and move with respect to the first frame; a drive actuator configured to rotationally drive the second frame with respect to the first frame; and a transmission mechanism configured to transmit the drive force of the drive actuator, wherein the second frame includes: a substantially cylindrical main body; a gear portion disposed on the inner peripheral face of the main body and to which the rotational drive force is transmitted by the transmission mechanism; and cam grooves including an inflection point in the range in which the zoom ratio of the optical system is varied, the transmission mechanism includes: a first transmission gear portion configured to engage with the gear portion; a second transmission gear portion disposed coaxially with the first transmission gear portion; and a clutch disposed between the first transmission gear portion and the second transmission gear portion, and the clutch is configured to temporarily disengage the drive force of the drive actuator transmitted to the first transmission gear portion, only with respect to one-way rotation.