GB671916A - Improvements in and relating to stereoscopic kinematography and photography - Google Patents

Abstract

671,916. Stereoscopic apparatus. DUDLEY, L. P. C. J. Oct. 14, 1948 [Oct. 14, 1947], No. 27532/47. Classes 97 (i) and 98 (ii). Optical means combined with or adapted to be fitted to a kinematograph or photographic camera having a single lens for use in the production of a stereoscopic pair of pictures comprises light deviating means, e.g. prisms or mirrors, disposed or adapted to be disposed sufficiently far in advance of the camera lens to prevent image overlap and a mask disposed in the film gate of the camera or near the light deviating means for obscuring one half of each film frame. As shown in Fig. 5, the light deviating means comprises two internally reflecting prisms 3, 4 of which prism 3 has one edge in a vertical plane passing through the optical axis of the camera lens 1. Prism 4 may be adjustable and is so arranged that the angle between the reflecting faces of the prisms is equal to one quarter of the angle of field of the lens 1 so that corresponding rays such as 5 and 6 emanate from a common object point. The prisms are so positioned that the rays reflected form the right-eye image r of a stereoscopic pair on a film 2, which image does not overlap the left-eye image l forms by rays received by the camera lens direct from the object. A mask which extends downwardly from the lens axis and covers half the field of the lens is provided so that the images land r each occupy one quarter of a normal film frame. The mask may alternatively be positioned so as to cover the vertical half of the lens field whereby the images l and r are justaposed one above the other on the film. The unexposed parts of the film may be exposed by running the film through the camera a second time and arranging the mask so as to cover the already exposed parts of the film. The optical means may be embodied in an attachment comprising a body portion and a base 19, a bracket 23 on which has an aperture for receiving a plug 24 which threads into one of the objective receiving apertures of the lens turret 22 of a camera 21. One of the lenses in the turret registers with an aperture 20 in the rear of the body portion of the attachment. An aperture 26 is provided in a re-entrant part of the body portion, the inner edge of this aperture being aligned with a line bisecting the aperture 20 in a vertical direction and the upper edge of the aperture 26 being aligned with a line bisecting the aperture 20 in a horizontal direction and through apertures 26, 20 light rays, such as 6, Fig. 5, enter the camera lens. Light rays, such as 5, Fig. 5, enter the attachment through an aperture 31 and are reflected by mirrors 28, 27 before passing through aperture 20. The upper edge of aperture 31 is in horizontal alignment with the upper edge of aperture 26 and the vertical edge of mirror 27 which is nearer aperture 20 is in a plane which bisects said aperture vertically.