Patent GB-634435-A (GB)
Title: Improvements in or relating to apparatus for instantaneous photography giving the impression of relief at variable distances
IPC: G03B35/24
Filed: 1946-05-27
Abstract: 634,435. Cameras for stereoscopic photography. RELIEPHOGRAPHIE SOC. POUR L'EXPLOITATION DES PROCEDES DE PHOTOGRAPHIE EN RELIEF M. BONNET. May 27, 1946, No. 15979. Convention date, June 14, 1945. [Classes 98 (i) and 98 (ii)] Photographic apparatus for recording simultaneously multiple negative images of the same subject, each image corresponding to a different viewpoint, comprising two horizontal rows of objective lenses, the optical axes of which are vertical and lie in a plane perpendicular to the sighting axis of the apparatus, and a central row of optical members for distributing alternately between the lenses of the two rows the rays of light coming from the subject, is characterised by two rows of optical members (e.g. mirrors or prisms) located beyond the lenses in the path of the rays, these members reflecting the rays in a direction substantially parallel to the sighting axis, so as to impress all the images upon a single light-sensitive surface perpendicular to the sighting axis. The body of the apparatus may be divided into a rear part and a front part, the rear part being movable, to photograph objects at various dis. tances, and may be divided into as many chambers as there are lenses by extensible and tiltable partitions. The apparatus can also be used to project the developed images to print positives thereof. As shown, Fig. 10, the front part A of the camera body, carrying the objective and a cylindrical shutter 4, is supported in a stand 62 which may be mounted on a turntable, and may be tilted by a worm 65 engaging a toothed sector 66. The rear part B slides on the part A for focusing, and carries the plate holder C. A range- and view-finder V is mounted on the back B. The shutter 4 has arcuate plates revolving on a common axis with an exposure slot formed -between them, and is removable from the part A. The objectives 6, 7, Fig. 1, are mounted in two rows in staggered relation, with their optical axes lying in a plane perpendicular to the sighting axis xy of the camera. Light rays admitted by the shutter 4 are reflected from a row of plane trapezoidal mirrors 8, 9, mounted on a bar 10, each mirror at 45 degrees to the objective axis and at right angles to the adjacent mirrors to reflect light into its corresponding objective. Light emerging from the lenses is reflected by two rows of mirrors 11, 12, mounted on bars 13, 14 at 45 degrees, to the light paths, and adjustable as by screws 55, 57, 58, to form two rows of images D, D on the plate S-S. Externally threaded rods 36, Figs. 3, 4, are rotatably mounted at the four corners of the part A and carry pinions 37 linked by a chain, one of the rods being driven by a handle 40 through bevel gears 38, 39. Bars 31 are fastened to nuts 35 moving on the threaded parts of rods 36 when the latter rotate, and are fastened to tubes 32, 33 to which the back B is bolted. The body A is internally divided into compartments, one for each lens, by partitions consisting of plates 16 sliding in guides on plates 15 hinged to the wall. Flat bars 29, 30 extend horizontally through slots 27, 28 in the plates 16, and move with the bars 31 and back B, causing the plates 16 to slide relatively to plates 15 to extend always up to the sensitive surface. At the same time, the inclination of the plates is varied as projections 21, 22 on the plates 15 slide in slots 23, 24 in stationary horizontal plates 25, 26. The slots 23, 24 are so inclined that the plates 15, 16 always converge on the object on which the camera is focused. A nut 45, Fig. 5, mounted on a ballbearing on one of the tubes 33, engages a quick-pitch screw 48 fast with the body A so that it rotates during the focusing movement. The nut 45 carries a disc 44, the edge of which enters a tube 49 and carries a scale of numbers indicating the focusing distance which is illuminated, at the moment of exposure only, by a lamp 42. The image of the scale number is projected by a lens 50 on to a corner of the plate. The range- and view-finder V, Fig. 8, has a field-defining aperture 71, and for rangefinding has a fixed semi-transparent mirror 69 and a rotatable mirror 70. The finder is mounted on trunnions on the back B, and has a pin 75 riding on a ramp 74 on the body A, whereby it is tilted by the focusing movement to compensate for parallax. Mirror 70 is rotated by a lever 76 riding on a ramp 77 on the body A to effect image coincidence. The dark slide C, Fig. 3, contains two plates back to back, and extends below the body A so that after an exposure the plate may be turned upside down, and the second set of images recorded on the unexposed parts of the plate. To print the images, the developed plate is placed in a frame and projected by the camera lenses, the focusing distance being set up, by the aid of the scale number recorded on the plate, to its original value. The focusing distance for projection may be reduced, if desired, by placing a supplementary lens in the optical path of each objective lens. Roll film may be used instead of plates. Specification 591,263 and French Specification 944,253 are referred to.