GB969639A - Photographic camera,more especially a single lens reflex camera - Google Patents

Abstract

969, 639. Exposure setting means in photographic cameras. AGFA A. G. July 7, 1961 [July 12, 1960], No. 24739/61. Heading G2A. A photographic camera for use with interchangeable objectives each including a variable aperture diaphragm spring loaded towards one extreme setting position, has an exposure value setting device including a setting member controllable by an exploratory device for the galvanometer of a photo-electric exposure motor and also includes a release member for holding the setting member in an idle position until the exposure value is to be set; the arrangement being such that when an objective is attached to the camera said setting member is spring urged by the objective's diaphragm setting means into contact with the release member so that in movement of the release member the setting member and means follow it until arrested by the exploratory device. In the reflex camera shown the diaphragm blades 6 are pivoted on a fixed plate 4 and a movable plate 9 which is urged by spring 11 in direction a to close the blades. A pin 13 on plate 9 engages a lug 15 on a rotatable control ring 14 which is also engaged by a lug 33 on a shutter setting and release ring 32. The ring 14 is operatively linked through parts 17-24 to a cam 27 which may engage the pointer 30 of a rotatable exposuremeter galvanometer 31. An exposure time setting ring 43 is connected through parts 51-61 to a rotatable member 63. By means of a rotatable knob 68 and scales 70, 71 the galvanometer may be rotated relative to member 63 to account for-film sensitivity and the maximum relative aperture of the objective and is locked by means of pins 69 in this position. When the exposure time setting ring 43 is subsequently rotated the member 63, galvanometer 31 and its needle 30 are rotated by a corresponding amount. When the shutter is released and ring 32 rotates in direction a, plate 9 and hence ring 14 are rotated in the same direction by spring 11 until cam 27 engages the pointer 27 and stops ring 14 and hence plate 9 and a diaphragm opening corresponding to the setting of pointer 30. The diaphragm can be set manually by means of a setting ring 37 with a lug 38 which acts as a stop for ring 14 and when ring 37 is set a cam 39 thereon closes a switch 40 and short circuits the galvanometer so that its pointer is in an inoperative position. In an alternative embodiment parts 51-63 are removed and ring 43 is detachably coupled to the plate 9 so that the exposure time may be set automatically.