Abstract: 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.

Abstract: A novel and advantageous microscope objective mount is provided. Said mount can be screwed to a microscope and more particularly to the objective turret or nosepiece. It is provided with a rotatable outer sleeve held on the mount, the sleeve being held by an elastically deformable ring which engages, at least in part, by force-locking. Due to the construction of the mount of this invention, attachment of the sleeve thereto is considerably facilitated and improved with respect to the axial play as compared with known mount assemblies. There is practically no radial clamping of the holding ring against the mount.

Abstract: Method and apparatus for measuring distance using an optical correlator system containing at least one imaging optic, at least one optically active array, and at least a system of photoelectric detectors associated with the array preferably in the form of an optical grating structure wherein for the purpose of unambiguous distance or range determination by means of optical-geometric steps in the image region and/or in the Fourier space, different beam guidance systems are constructed so that for axial relative motion between object image and array output signals are generated at each photoelectric detector system associated with each beam guidance system, these output signals differing among themselves in frequency and hence (also) in phase. A comparison is made of the output signals and from the comparison the geometric image position of the principal maximum is determined with respect to the geometric positions of the secondary maxima.

Abstract: Disclosed is a method for automatically determining parallax in a stereoscopic system, comprising the steps of: passing at least two imaging light channels through a moving grating structure; converting the light rays into separate electrical signals after passage through the grating structure; subtracting one of the electrical signals from the other to produce a signal difference; differentiating one of the electrical signals to produce a differentiated signal; multiplying the signal difference by the differentiated signal to produce a first multiplied signal; and controlling the orientation of one of the imaging light rays in response to the multiplied signal. Also disclosed is our apparatus for carrying out this method.

Abstract: A semi-automatic coarse-fine focusing apparatus for microscopes adjusts the focus of a microscope through rotation of a shaft which rotates a pinion that drives a rack to reciprocate. The rack carries a specimen being observed by the microscope. The shaft which rotates the pinion is in turn driven by a gear that is meshed with a helix formed on a cylinder by a helical thread disposed therearound. The helix is non-rotatably mounted on another shaft that includes a knob which is manually turned to turn the helix and thus rotate the gear for coarse adjustment. The helix is preferably rigidly mounted on the shaft and the shaft is slidable. One arm of a bell crank engages an end face of the helix to reciprocate the helix and thus rotate the gear for fine adjustment. The other arm of the bell crank is engaged by a cam which pivots the bell crank according to the position of the cam. The position of the cam is determined by an electric motor which is preferably controlled by signals that vary with image contrast.

Abstract: Apparatus for the photoelectrical determination of the position of at least one focusing plane of an image comprising an imaging optics, at least one spatial frequency filter in the form of a structure or grating mounted in the vicinity of one image plane of said imaging optics, a photoelectric receiver system associated with the filter containing at least one detector and receiving light fluxes leaving this filter, at least one means for generating a relative motion between the structure or grating and the object image, and means for analyzing the output signals from the photoelectric receiver system for distance display and/or focusing of the apparatus. The apparatus is improved by having the imaging optics (10) preceded by wo rhombic prisms (19, 20) so that each pupil half obtains its light through one of the two prisms. A reference beam is provided to show and/or eliminate mechanical changes in the apparatus effecting faultiness of the measuring result.