US 4,072,969 AGranted

Ranging system for camera viewfinder

AssigneeBalda-Werke Photographische Gerate und Kunststoff GmbH & Co., KG

InventorMichael Cheavin

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Abstract

A ranging system for a camera is provided including a reflecting means and marking means including movable masking means reflected thereby into the viewfinder of a camera. The reflecting means within the scope of this invention includes means for translating an axial movement of the movable masking means to the camera viewfinder as a positional movement transverse to the actual displacement direction thereof. To effect this image transfer, the marking means includes at least one mirror mounted adjacent to the masking means at an angle of about 45 degrees to the displacement direction thereof. According to one embodiment of the invention, an annular mark is projected into the viewfinder. To project an image of this character, the marking means includes an interiorly mirrored conical member, and the masking means includes a mandrel axially mounted therein, the mandrel being displaceable along the conical axis. According to another embodiment of the invention, the marking means includes mirrored polyhedronal side walls and the masking means includes a polygonal member movable within the area of the mirrored side walls.

Claims10

Dependent claims

An improved ranging system for an encased camera of the type having an objective lens mounted in said camera casing, and focusing means therefor, said ranging system being of the type including an optically aligned eyepiece and viewfinder lens defining a field of view for an operator looking through said system, said field of view including the scene to be photographed, said improving ranging system comprising, in combination, a luminous marking means lying substantially in the plane of said viewfinder lens, said marking means including a movably mounted masking means, said masking means being axially movable substantially at an angle normal to said plane of said marking means, said movable masking means including a reflective surface which is angularly oriented at about 45.degree. to said axis of movement thereof, said marking means including a mirrored surface corresponding to said reflective surface which is similarly angularly oriented;

means for axially moving said masking means, said moving means being operatively connected to said focusing means for axially displacing said masking means in correspondence to a focusing movement;
and means for superposing an image of said marking means in the line of sight between said eyepiece and said viewfinder lens, said means translating an axial movement of said masking means into a laterally displaced image transfer in the line of sight between said eyepiece and said viewfinder lens.

Dependencies are inferred from the claim text.