Abstract: A lens barrel comprises an outer sheath internally formed with a detent step, and an inner sheath formed with a plurality of slits which are open at one end thereof and with an outward projection located on said one end and a moveable lens disposed within said inner sheath for axial movement therealong upon a relative rotational movement between said inner and outer sheath whereby relative axial movement between the inner and outer sheath is prohibited. Provision of bevelled surfaces for engagement between the outward projection and the detent step minimizes the influence of dimensional variation the inner and outer sheaths.

Abstract: A focussing apparatus is disclosed comprising a mask plate disposed in the path of light to a camera rangefinder and having a plurality of apertures of like configuration which are offset from the optical axis of the rangefinder. Light passing through the respective apertures forms on the focal plane of the rangefinder a number of separate images of an object photographed which are equal in number to the number of the apertures. Focussing is achieved by a displacement of a focussing lens in the taking lens system in the direction of the optical axis in a manner to bring the separate images into a single aligned image.