GB1233037A - - Google Patents

Abstract

1,233,037. Cameras. PENTACON DRESDEN KAMERA-UND KINOWERKE VEB. Nov.26, 1968, No.56052/68. Heading G2A. In a single lens reflex camera having interchangeable lenses with diaphragms which close to preset values on shutter release, the reading on a through-the-lens light meter is adjusted according to the maximum aperture of the particular lens, by means of a lug on the lens; the camera and its light meter also being usable with lenses not having correction lugs. In Fig.2, a lens 5b has a fixed lug 10b which rotates the casing 2 and thus the needle 4 of a light meter galvanometer, through an arm 9 thereof, a distance corresponding to the maximum aperture of the lens 5b. A lug 17b which presets the diaphragm value, is adjusted, by diaphragm ring 18b until, by means of an arm 16, it has brought a needle 12 into coincidence with the needle 4. A scale 18 indicates the f number to which the aperture will thus be closed. When a lens without lugs 10b, 17b is attached, springs 6, 13 move an arm 14 of needle 12 and an arm 7 of galvanometer 2 into abutment with stops 8, 15. These positions correspond to the maximum diaphragm values. The correct diaphragm value in this case is found by closing the diaphragm until the needle 4 moves into coincidence with needle 12. In an alternative embodiment, Fig.4, a correction lug 28b, corresponding in length to the maximum aperture of a lens 25b, is fixed to an adjustable diaphragm-setting lug 27b. The position of the left-hand end of the lug 28n of any lens 25n, when the lug 27n is set to the maximum aperture of that lens, is the same so that an arm 28 of a needle 26 always abuts a stop 29 initially. The correct exposure is set by adjusting the diaphragm-setting lug 27b until the needle 26 coincides with the galvanometer needle 24. The diaphragm value which has thus been preset may be indicated on a scale by means of levers 31, 32. When a lens without lugs is attached, the arm 28 engages the stop 29 and the diaphragm is closed until the needle 24 is opposite the needle 26. A scale 23 may indicate, for example, exposure times, so that the position of the galvanometer may be adjusted accordingly.