GB925531A - Still camera attachment - Google Patents

Abstract

925,531. Periscopic attachment for cameras in aircraft for firing practice. PERKIN-ELMER CORPORATION. June 23, 1961 [July 7, 1960], No. 22861/61. Classes 97 (1) and 98 (1). An adapter for a camera in an aircraft for use in firing practice, designed so that the view presented to the camera is the same as that of the pilot and the light path to the camera is turned through a number of angles so as to avoid the pilot or obstructions in the cockpit, comprises a periscope structure 14 having a light inlet 32 for receiving parallel light from a distant object, a light outlet for application to the camera objective 110 and an even number, which is at least four, of reflecting surfaces for folding the light path, one of the reflecting surfaces being adjacent the inlet at 42, the periscope structure also including towards the inlet a first positive lens system 50 which focuses parallel rays at a plane I 1 , a Petzval curve corrector 62 for rendering anastigmatic the image formed by the system 50, a second Petzval curve corrector 66 and a second positive lens system 70 with their combined focal point at the image plane I 1 for producing parallel light for application to a second, magnifying lens system disposed towards the outlet and having a positive lens group 160 and a Petzval curve corrector 84 for producing an anastigmatic image at a plane I 2 , and a second Petzval curve corrector 88 and a second positive lens group 90 with their combined focal point at the image plane I 2 to produce parallel light for application to the camera objective 110. As shown, there are six reflecting surfaces, there being, in addition to the surface 42 at the inlet, one 68 between the corrector 66 and the lens group 70, two reflecting surfaces 153, 154 between the two lens systems, one 172 between the lens group 160 and the corrector 84, and one 100<SP>1</SP> at the outlet. Preferably, each of the two lens systems is symmetrical with respect to its intermediate image plane and the magnifications of the first and second systems are unity and 1.4 respectively. The prism 40 is adjustable both about an axis 184 parallel to the reflecting surface 42 and perpendicular to the optical axis 46 of the periscope and about this axis 46. An image of a reflex reticle sight 10 is combined with the scene by an inclined glass plate 30.