Abstract: A lens tube for a high vari-focal ratio zoom lens is arranged to individually effect movement of a plurality of lens groups for the purpose of zooming, and to integrally move a plurality of lens groups of the purpose of focusing, and arranged so that a double helicoid mechanism for driving the first lens group is provided on a member constituting the lens tube, the lens tube being arranged so that operation of a zooming mechanism serves to move a focusing mechanism, for the purpose of compensation, by means of the helicoid mechanism mentioned above, and a cam mechanism provided on other members constituting the lens tube.

Abstract: A lens barrel having a moving frame moving in a direction of an optical axis of a zoom lens or the like, wherein the outer surface of the moving frame is not slidably moved in contact with the inner surface of the barrel. Instead, multiple guide grooves and an engaging member slidably moved along the guide grooves are provided on the barrel and the moving frame in such a manner that they are not positioned only diametrically on the barrel. Elimination of a rattle or play in the contact between the guide grooves and the engaging member is made easier, and any inner reflection from lubricant on the sliding surface can be avoided.

Abstract: A manual focus setting apparatus for a camera having an automatic focus adjusting or focusing apparatus including an actuator which moves simultaneously or in synchronism with movement of a focusing lens along its optical axis and is stopped in response to a signal from an electromagnet. A focus setting member is manually movable from a position clear of the path of a stopper projection on the actuator to a position where it can engage the stopper projection to limit movement of the actuator. Switch means is provided which is operable in response to movement of the focus setting member to the stopper projection engaging position to inhibit operation of the electromagnet.