Abstract: Apparatus for the retracting and extending the lens holder of a camera, which comprises two gear wheels or gearwheel segments swingably supported about fixed axes on different sides of the longitudinal central plane of the lens holder, said gear wheels or gear-wheel segments being in direct or indirect engagement with each other, two stationary toothed members, two swingable segments coupling said lens holder and said gear wheels or gear-wheel segments, said gear wheels or gear-wheel segments, when swung, being operable to retract and extend said lens holder via said swingable segments and to move said swingable segments over the toothed segments as said lens holder is extended from its fully retracted position, such that with equal paths of swing of the gear wheels or gear-wheel segments, the lens holder is displaced by a larger amount in the vicinity of the retracted position than in the vicinity of the extended position.