Patent GB-693174-A (GB)
Title: Improvements in or relating to stereoscopic photography and cinematography
IPC: G03B17/56
Filed: 1950-07-07
Abstract: 693,174. Stereoscopic photography and kinematography. DUDLEY, L. P. C. J. July 6, 1951 [July 7, 1950], No. 17086/50. Classes 97 (i) and 98 (ii)] To record photographically stereoscopic pairs of pictures, two cameras are supported in positions facing each other with a mirror reflecting a left-eye view to one camera and a second mirror reflecting a right-eye view to the other camera, and each camera support is movable in a direction parallel to the surface of the associated mirror. Preferably at least one of the mirror supports and its associated camera support is angularly adjustable about a vertical axis and both may be so adjusted by a single mechanism to vary the angle between the mirrors without moving the angle bisector. The cameras may be adjustable on their supports to vary the angle between the optical axes and may be movable along the supports to alter the distance from the associated mirror. As shown, two platforms 7, 8 are mounted as on slideways or by means of rollers on a base 5 for rotation about a vertical axis at the front adjacent extremities and are controlled by a hand wheel 9 mounted on a shaft in screw-threaded engagement with a cross-head located beneath the platforms and having pins extending upwardly into slots disposed in the platforms to effect rotation of them upon rectilinear movement of the crosshead by the hand wheel shaft. Each platform carries a support 10 or 11 for a mirror 12 or 13 and guides 14 or 15 along which are slidable carriages 16 or 18 supporting beds 20 or 21 along which kinematograph cameras 17 or 19 are longitudinally slidable by means of handwheel-controlled lead screws. The mirrors have their forward adjacent edges or the intersection of the planes of the mirrors on the pivotal axis of the platforms and the angle between the mirrors has a minimum value of 90 degrees at such position of minimum value the cameras and beds being aligned and facing each other. A lever 27 secured to the shaft of a gear-wheel 29 meshing with a second gear wheel 30 controls movements of the camera carriages 16, 18 along the guides 14, 15, a link 31 or 32 being pivotally secured eccentrically to each gear and having at its far end a longitudinal slideway in which is located a shoe receiving a pin depending from the carriage. The carriages are movable along the guides to vary the length of the stereoscopic base and the cameras are movable along the beds to permit use of lenses of different field angles at a minimum steroscopic base, such longitudinal movement of the cameras causing slight alterations in the stereoscopic base except when the mirrors are at 90 degrees, while variation of the angle between the mirrors together with the panning and tilting movement of the tripod head by means of a lever 28 allows the selection of a chosen point in the field view to which the axes of the two camera lenses converge. The two cameras are driven in synchronism by motors 24, 25 connected by a flexible shaft 36, while simultaneous changes in focus of each objective is achieved by a flexible coupling 37 connecting the shafts 34, 36 which are geared to the objective focusing rings.