Patent GB-666856-A (GB)
Title: Improved photographic reflex camera
IPC: G03B19/12
Filed: 1948-03-17
Abstract: 666,856. Reflex photographic cameras; stereoscopic photography. RELIEPHOGRAPHIE, SOC. POUR L'EXPLOITATION DES PROCEDES DE PHOTOGRAPHIE EN RELIEF M. BONNET. March 17, 1948 [March 17, 1947], No. 8012/48. Classes 98 (i) and 98 (ii). A reflex camera comprises a lower wedgeshaped camera chamber having a camera lens at its smaller, front end, means for accommodating photographic material at its larger, rear end, and a retractable mirror at an intermediate point; an upper viewing chamber of roughly pyramidal form carrying at its larger front end an inclined mirror and having at its smaller rear end two optical inverting systems through which a focusing screen at an intermediate point can be viewed; and a convergent lens interposed between the two mirrors in a wall common to the two chambers. As shown, a wedge-shaped chamber 1 and a truncated roughly pyramidal chamber 2 are disposed with one face of each in contact and with the axis of the pyramid approximately parallel to the medial plane of the wedge, the smaller end of the truncated pyramid being adjacent the larger end face of the wedge so as to form a roughly cuboid structure having a laterally reduced rearwardly tapering upper portion. An objective 3 comprising a row of beam-inverting elements C between two lenses A, B of rectangular apertures is arranged in the smaller end face of the wedge chamber 1 which forms the camera proper, a dark slide 4, in which are housed a photographic plate 5 and a lenticular screen 6, being arranged at the rear of the chamber, and between it and the objective a unit comprising a cylindrical shutter 22 and a reflex viewing mirror 11 secured to a pivot 12. The reflected image is formed in the viewing chamber 2 on a frosted screen 13, which may be one face of a lens 18, by means of a lens 17 in the party wall 9 and a mirror 8 on a door 7 at the front of the chamber 2. The image on the screen 13 is viewed through two beam-inverting Dove prisms 16, and a series of masks, having apertures of zones related to the photographic plates which can be used, can be inserted close to the screen in a slot 14. The shutter 22, of the kind described in French Patent 944,253, comprises two concentric part-cylindrical members carried on trunnions 23 and having apertures parallel to the cylinder axis which are given differential movements by the shutter operating mechanism to form a travelling exposure slit. The shutter releasing means comprises a manual release 24 adjacent a hand grip 25 which through a rod 27 rotates a three-armed lever pivoted at 29. The initial movement of the three-armed lever releases a projecting arm 37 secured to the pivot 12 of the mirror 11 which is spring-urged to the horizontal viewtaking position. Further movement of the three-armed lever is arrested by engagement between the hooked end 33 of the arm 32 and a cam 38 attached to the mirror pivot until the mirror is horizontal when the end 33 falls into a recess in the cam locking the mirror and depressing the shutter button 36 to make an exposure. The camera is mounted on a fixed frame by trunnions 39, and its elevation is determined by the position in which a sector 54 on it is clamped by two spring-closed jaws carried by the frame and whose opening is controlled by a pulley and lever system operated by a manual trigger adjacent a second-hand grip on the opposite side of the camera to the grip 25. Specification 639,406 is referred to.