Abstract: Slide projectors with automatic focusing systems consisting of a scanning auxiliary projecting system and a position control focusing the slide and comprising a light sensor detecting the reflections from the slide are improved by mounting the light sensor outside the scattered light zone generated when the main projection beam passes through the slide. The light source of the auxiliary projecting system is operated at less than rated voltage and silicon cells are used as light detectors. The light course comprises a lens which is mounted in the same manner as the light sensor on holders and the holders are pivotably supported for the purpose of adjustments.

Abstract: A slide projector with controls for the slide changing system and for the stop associated with the slide changing system where there are separately moving insertion and storage feeder arms for the slide changer, and at least two routes for inserting and removing the slides. Preferred motor driven cams (B",R",S",T") act as controls for the stop (8,11) and for slide changing and are operationally timed so that the closing process for the stop is initiated simultaneously or nearly simultaneously with the beginning of the removal of the projected slide (19a) from the slide stage plane and with the insertion of a new slide (19c). The process of stop opening begins immediately and without any pause after the complete closure of the stop which coincides with the terminated insertion of the new slide.

Abstract: In a slide projector having a partioned magazine for insertion into a magazine guide track so that the in turn, effective ejection side of the magazine is at right angles to or generally at right angles to the horizontal film aperture, the improvement comprising the operative bearing side of the magazine opposite the leading edge of the image stage side of the contained slide in the projector is foreshortened and the magazine guide path (1), considered in crosssection, is provided with a step (7) at least in the region of the film aperture (6), the profile of this step (7) adapted so that the bearing side (8) of the magazine containing a slide (10), and the face (10a) of the step which is situated at a higher level and thus suitable for receiving the slides as soon as the magazine is inserted, continues in the form of the film aperture (11).