Abstract: The clearance-free fit for cylindrical mountings, in particular photographic lenses, is produced by recesses in the inner wall of a main mounting and projections in the outer wall of an individual mounting, to be fastened in the main mounting by inserting and by a relative rotary movement between the two mountings. The recesses and the projections are of such a configuration that a sufficiently large clearance s is present when the individual mounting is inserted, and this clearance is removed by turning to produce a frictional connection.

Abstract: Apparatus for at least partially compensating for the rebound impact of an automatic diaphragm in a photographic objective comprising a diaphragm control ring for driving the leaves of the diaphragm and a diaphragm preselector ring for predetermining the diaphragm aperture; the rebound impact being defined as the recoil produced according to the laws of elastic collisions when the diaphragm control ring which shuts the diaphragm engages the stop of the diaphragm preselector ring; said apparatus comprising at least one movable auxiliary mass which frictionally opposes the rebound movement.

Abstract: A process and apparatus for the alignment of the image plane of an imaging system with the interception plane of the image utilizing a measuring mark reproduced by at least two partial pupils of the imaging system. The two imaging beams associated with the partial pupils are distinguishable from one another and at least one partial pupil is moved over the full pupil of the imaging system. A minimum movement of the image of the measuring mark corresponds to alignment of the image and interception planes.