Patent ID: 9213170
Filing Date: 2015-12-15
Classification: G02B

Abstract:
1. A lens barrel comprising: an image-pickup optical system configured to form an optical image of an object, the image-pickup optical system including a main optical system and an extender optical system configured to change a focal length of the image-pickup optical system; an extender barrel configured to hold the extender optical system; a housing configured to house the extender barrel; a rotator configured to: a retreat restraint having a first state used to restrain a retreating amount of the extender barrel by the rotator and a second state used to make the retreating amount of the extender barrel larger than that in the first state, wherein, when the retreat restraint is in the first state, the extender optical system is retreated to a position that is not associated with formation of the optical image, but the extender barrel is undetachable from the rotator, and wherein, when the retreat restraint is in the second state, the extender barrel is detachable from the rotator.