Patent GB-624689-A (GB)
Title: Improvements in or relating to producing photographs giving the appearance of relief
IPC: G03B35/24
Filed: 1945-11-05
Abstract: 624,689. Stereoscopic photography. RELIEPHOGRAPHIE SOC. POUR L'EXPLOITATION DES PROCEDES DE PHOTOGRAPHIE EN RELIEF M. BONNET. Nov. 5, 1945. No. 29392. Convention date, Nov. 17, 1944. [Class 98 (ii)] Apparatus for producing photographs exhibiting relief effects, in which the camera containing a frame holding a cylindrically lenticulated screen and photographic plate is traversed along a rectilinear path and simultaneously rotated so as to point at the object to be photographed, comprises a carriage, movable parallel to a line xy syminetrically about the object, on which the camera is pivoted at a point on the line xy at a distance L from a rod perpendicular to xy carrying a roller which rolls along a fixed ramp VW at an angle α to xy and a projection which engages a member carried by the camera at right angles to the optical axis, so that as the carriage is displaced laterally the camera always points towards an object. Situated at a distance b given by the equation b=L cot α. Since the angle through which the camera pivots is not greater than the aperture angle of the lenticular screen elements, i.e. the ratio of their effective diameter to their focal length, which is 16 degrees, the variation in object distance does not cause appreciable loss of focus. As shown, the distance of the object from the pivot of the camera is varied by changing the length of the segment L. A carriage 11; which is guided along a rectilinear path by rollers 13, 14 engaging the sides 15 of a table 9 and carries a trunnion 17 upon which is mounted the under frame 18 of a camera 19, has arms 21 supporting bearings 22, in which is slidably journalled a rod 26 carrying a roller 27 pressed by a spring 28 against a ramp 10 fixed on the table, and also a tenon 51 (see Fig. 12) which engages in the fork of an arm 29 attached to the underframe of the camera at right angles to its optical axis. The point at which the camera is directed may be changed by disposing the bearings 22 in pinions 50 (Fig. 12) engaging racks 49 on the arms 21, so that on rotating the knob 53 the rod 27 is traversed laterally and the roller 27 rides along the ramp in the same direction, its point of mounting on the rod 26 being changed simultaneously by the nut 52 supporting the roller moving along the threaded length of the rod so that the camera always points directly forward when in the central position. The frame carrying the lenticular screen and photographic plate is mounted on a rod 34 which slides in guides 37 on the carriage 11 and is thereby constrained to remain parallel to the sides 15 of the table 9. The camera may be traversed by an electric motor and may carry the movable contact 39 of a switch having an arcuate contact 38 fixed on the frame 18 so that the camera is stopped and, if desired, its shutter closed when it has pivoted through a chosen angle, usually the aperture angle of the lenticular screen elements, viz. 16 degrees. In an alternative construction (Fig. 7, not shown), the distance b is varied by changing the angle a. The apparatus is generally similar to that already described, but the bearings 22 are fixed on the arms 21 and the ramp 10 is adjustable rotationally on a pivot disposed on the line xy, the object distance being indicated on a scale by a pointer arranged perpendicular to the ramp. Also the linear traverse of the camera is fixed and hence the angle traversed varies with object distance. Thus, to ensure that the whole of sensitive surface is exposed, an arm, which is pivoted to a push-rod carrying an inclined ramp vertically displaceable by a vertical rod slidably journalled in a sleeve fixed to the rear wall of the carriage 11 and engaging an oppositely inclined ramp fixed to the table 9, so that the traversing movement of the carriage rocks the arm in a vertical plane, actuates means similar to those described in Specifications 117,342, [Class 98 (ii)], and 370,702 for sliding the screen relatively to the sensitive surface.