Lens barrel and camera

A lens barrel for supporting an imaging optical system, comprising:

• a cylindrical first support frame having on an inner or outer peripheral face thereof at least three first guide grooves disposed aligned in the circumferential direction;
• a cylindrical second support frame provided on the inner or outer peripheral side of the first support frame and having at least three first pins inserted in the first guide grooves;
• a drive part configured to produce a relative rotation of the first and second support frames;
• and
• a control part configured to control the operation of the drive part,
• the first guide grooves having
• a retracted region configured to guide the first pin so that the relative positions of the first and second support frames are changed along the optical axis of the imaging optical system in response to the relative rotation of the first and second support frames, the retracted region including a retracted position at which the overall size of the first and second support frames in a direction along the optical axis is shortest;
• a first imaging region disposed adjacent to the retracted region and including a wide-angle position corresponding to the wide-angle end of the imaging optical system, the first imaging region having a substantially linear shape;
• a second imaging region configured to guide the first pin so that the relative positions of the first and second support frames are changed along the optical axis in response to the relative position of the first and second support frames, the second imaging region including a telephoto position corresponding to the telephoto end of the imaging optical system;
• and
• an unusable region disposed between the first and second imaging regions and coupling the first imaging region to the second imaging region, and
• the control part configured to limit the drive region of the drive part so that the first pins do not stop in and are driven through the unusable region.