Abstract: The application describes an automatic focusing system for photographic cameras. The system functions by means of an infrared light source and an infrared detector. The infrared radiation is focused as a function of object distance in such a manner on the detector that this detector is divided into two detector segments each of which supplies a partial current of which the ratio depends directly on the object distance. The detector is followed by an electronic computing circuit which sets the objective as a function of a preselection implemented by a switch to one of the following modes of operation:(a) the focus is on the object to be photographed(b) the depth of field is extended from the object toward the camera(c) the depth of field is extended from the object to the rear(d) the depth of field is extended from the object to infinity(e) the depth of field is extended to between two consecutively targeted objects.

Abstract: A microfiche and a microfilm reader comprising automatic positioning of the film stage, characterized by the following features:(a) the microfiche (MFK) is provided with an index (2) of the information present in its individual images and of their x,y coordinates in optically coded form and with a timing track (4),(b) the reader comprises a read head (19) with electronic-optical sensors to read the optically coded index on the microfiche (MFK),(c) an electronic read/write memory (20) for storing the index (2) is connected to the read head (19),(d) provision is made for an alphanumeric keyboard (27) to feed-in a search concept (search key) and followed by an encoder (26) and a register (25) for storing the coded keyboard input,(e) a comparator (24) is connected to the memory (20) of the index (2) and the register (25) of the coded keyboard input, which determines the agreement between the search key and a concept present in the index,(f) the comparator (24) and the memory of the index are followed by appropria