Abstract: An apparatus for detachably attaching an accessory to a lens barrel, wherein the front end of the lens barrel and the accessory are provided with engaging members which are engaged and disengaged only when a predetermined angular relationship between the lens barrel and the accessory is met. The accessory is provided with at least one roller which is rotatably supported by a shaft extending parallel to an optical axis of the lens barrel. At least one abutting surface is provided on the front end of the lens barrel, and comes into contact with the roller or rollers of the accessory during rotation of the accessory while in contact with the lens barrel.

Abstract: A lens barrel for an automatic focusing camera is provided with an annular changeover member arranged so as to be manually rotatable about the optical axis, and further arranged so as to be manually movable in a direction of the optical axis. A first clutch mechanism is provided for releasing a connection between the annular changeover member and an annular focusing member, to permit independent rotation thereof, when the annular changeover member is in an AF mode setting position, and for forming the connection therebetween to thereby form a rotationally dependent structure when it is in an MF mode setting position. A second clutch mechanism is provided for forming a connection between a drive shaft and the annular focusing member when the annular changeover member is in the AF mode setting position, and for releasing the connection therebetween when it is in the MF mode setting position.

Abstract: An engaging mechanism of a stepped guide groove having an inner narrow groove portion and an outer wide groove portion and a roller which is provided with an outer larger diameter portion which is fitted in the outer wide groove portion and an inner small diameter portion which is fitted in the inner groove portion with a clearance therebetween so as not to come into contact with the wall surface of the inner narrow groove portion.