GB334328A - Improvements in or relating to focusing cameras - Google Patents

Abstract

334,328. Mottlau, A. J. July 11, 1929. Focusing devices.-The lens of a folding camera slides laterally into an adjacent position, for focusing, drawing a slide to cover the exposure opening, and a magnifying focusing device 17, Figs. 1 and 3 normally mounted in a housing 15 forming a lateral extension of the camera body 10, is movable out of the housing for focusing. In one construction, the focusing device comprises a tubular mount 17, pivoted at 18, and containing a small screen 20 and eyepiece 21. In a modified construction, the mount 54, Fig. 8, is fitted with an eyepiece 63 and a prism, the face 60 of the prism being in the equivalent focal plane. The mount 54 is pivoted on an extension wall 51 of the camera back 50 on a pivot 55 parallel to the optical axis, and can be held in the two positions indicated for horizontal and vertical pictures. Alternatively the focusing tube can be fitted with a prism 72, Fig. 9, having clear faces, a plano convex lens 75 adjacent one face and a focusing eyepiece 77. To close the exposure opening 26, Fig. 4, of the camera when the lens 41 is moved laterally into focusing position, the lens is mounted on a lens board 33 which slides in guideways 30, Fig. 1, on the camera front 25. The lens board has a lateral extension 34 with a projection 35 which engages a groove 39 in a rear slidable coverboard 38. On sliding the lens into focusing position, the extension 34 first covers the aperture 26 and then draws the coverboard 38 to maintain the cover. The lens shutter is opened for focusing by a lever 42 which engages a pin 43 on the camera front.