Lens barrel

A lens barrel holding a lens system therein, the lens system having a plurality of lens groups each having one or more optical elements, the lens barrel comprising:

• a fixed tube on which a guide groove that is along an optical axis direction and where a cam follower enters is formed;
• a cam tube rotatably provided with respect to the fixed tube, and having a cam groove where the cam follower enters and that is oblique with respect to the optical axis direction;
• a moving mechanism unit that changes a focal distance or a focal position by moving at least one lens group out of the lens groups, as a moving lens group, in the optical axis direction;
• and
• an adjustment mechanism for adjusting a position in the optical axis direction of at least one of the optical elements constituting an adjustment moving lens group being at least one of the moving lens groups, wherein:
• the moving mechanism unit includes:
• a moving holding frame to which the cam follower is attached, and that moves in the optical axis direction in accordance with a relative rotation of the cam tube with respect to the fixed tube;
• and
• a movable lens holding frame that holds at least a part of the optical elements of the moving lens group;
• and
• the adjustment mechanism includes:
• a fixed side hole part that penetrates the fixed tube;
• a cam-side hole part that penetrates the cam tube, and that is aligned with the fixed side hole part when the cam tube is rotated with respect to the fixed tube;
• a driving transmission part that is provided on an outer peripheral side of the movable lens holding frame in the same straight line as the fixed side hole part and the cam-side hole part in a state where these hole parts are aligned;
• an inner peripheral engagement part that is formed on an inner peripheral surface of the moving holding frame;
• and
• an outer peripheral engagement part that is formed on an outer peripheral surface of the movable lens holding frame in a state of engaging with the inner peripheral engagement part, and moves the movable lens holding frame in the optical axis direction by rotating with respect to the inner peripheral engagement part when an external force is transmitted in a rotational direction via the driving transmission part.