Ernst Leitz Wetzlar Gmbh

Werner Holle

Walter Bletz

Dietrich Bruckner

An apparatus for electrooptically focusing the objective in a single lens reflex camera provided with a focusing screen and a split image wedge rangefinder, where focus detectors are used in which an image segment is scanned in an image plane. The focusing window of the focusing screen provided with a split image wedge rangefinder (5) is followed by a pentaprism (8) having a first plane reflecting surface which is partly reflecting. The scanning grating (14) and the photoelectric detector system (17,18) are mounted in the direction of the light beam behind this plane surface of the pentaprism and along the optical axis deflected by one of the wedges (5a) and an optics (11) is present along the optical axis to image the plane of one of the wedges (5a) into that plane where the scanning takes place.

Electrooptical focusing apparatus for photographic cameras

An improved scanning grating useful as an image scanner and spatial frequency filter, for a focusing detector to ascertain the focus of an optical system on deflecting the light incident from the optical system into two different directions for forming two images of the exit pupil or of parts thereof of said optical system. A slit grating is superimposed over the groove grating so that the ledges cover the peaks and the troughs thereof. It is thereby attained that the signals obtained from the peak and trough areas, which normally are more or less undefined, are exempt from evaluation. The ledges have a width ranging from 10 to 100 percent of that of the slit width.

Scanning grating for a focus detector

An optical system for the metering of illumination in photographic cameras, in particular mirror-reflex cameras, which makes use of a photodetector with a light-sensitive surface small in comparison to the image area to be metered and which is mounted in the lower camera space. A honeycomb mirror consisting of a multitude of convex or concave mirror elements is mounted behind the reflex-mirror which is partly transmitting. The honeycomb mirror when it is in the metering position is located in front of the film plane and is moved together with the reflex-mirror out of the way of the beam path before the picture is taken, the mirror elements of the honeycomb mirror being slanted so that the center of every individual element reflects the principal rays toward the photodetector. The curvature of the mirror elements is such that the outermost peripheral rays from the objective are reflected from the rims of the mirror elements toward the photodetector.

Optical exposure measuring system for photographic cameras

Apparatus for indicating and displaying the focus of an optical objective and particularly a photographic camera. An image of the object is projected by means of the objective onto a scanning disk or plate where the light rays are divided into two separate light beams originating from two different areas of the exit pupil of the objective. Two photoelectric detectors are provided behind said scanning disk with one of said light beams impinging on one detector. Each detector delivers an electrical signal, the phase difference between these signals being a measure of the degree of focus of the objective. For indicating said degree of focus two LED's (Light Emitting Diodes) are provided which are so coupled that for focus (phase difference = null) they are equally luminous and that for lack of focus they indicate the direction of the image offset from the focusing plane and approximately also the magnitude of this offset on account of their special coupling and their change in luminosity which is independent of object brightness.

Growing community of inventors

Wetzlar, Germany

Werner Holle