Abstract: Disclosed is a photographic objective with a long focal length and a fastening device for a stand comprises a tubular structural element carrying optical elements, surrounded by an essentially annular holder. This holder is stationary in the axial direction and rotatable around the structural part. In addition to the fastening element capable of being joined to the stand, there is mounted in the outer wall of the holder means for locking the holder in predetermined positions.

Abstract: Disclosed is an adjusting device for a lens system having at least two optical elements displaceable parallel to the optical axis, the paths of displacement of which are subject to different courses of movement. To produce linear displacement parallel to the optical axis, a tube is arranged in the adjusting ring, which is rotatable and displaceable parallel to the optical axis. This tube serves as the mount for an optical element and has in the wall of one of its ends a guide groove. A hollow cylinder, serving as the mount for the other optical element and being displaceably mounted in the tube, has a guide element mounted on its external wall which engages the guide groove. Means are provided to drivingly connect the adjusting ring and the hollow cylinder.

Abstract: A compensating mechanism is provided on the leaf guide ring of a photographic objective for single-lens mirror reflex camera which opens to its largest value after a picture is taken in response to the hinge motion of the camera reflex mirror. The mechanism compensates for the advance of the diaphragm control lever on the camera side controlled by the reflex mirror.

Abstract: A photographic camera arrangement is disclosed for cameras which are intended to accept only certain interchangeable lens assemblies. For identification purposes, the bayonet segments of the camera housing and the bayonet segments of the lens assembly, respectively, are furnished with depressions, notches or like recesses and with stubs, ridges or like protrusions which will permit attachment of certain lens assemblies to only a given camera or series of cameras.

Abstract: In an interchangeable lens assembly for single lens reflex cameras the f-stop preselection ring is provided with a first transmission element for transmitting the preselected f-stop value into the light metering instrument of the camera housing, and with a second transmission element for controlling a device in the camera housing which indicates the preselected f-stop value. Said first and second transmission elements are parts of one common setting member which is in such a manner fixedly mounted on the preselection ring that -- when the preselection ring is in its base position -- said first transmission element assumes the same position in all interchangeable lenses while said second transmission element assumes positions that vary according to the maximum opening of the lens.