Patent GB-1014281-A (GB)
Title: Automatic exposure control apparatus
IPC: G03B17/26
Filed: 1962-05-10
Abstract: 1,014,281. Photographic cameras. EASTMAN KODAK CO. May 10, 1962 [May 11, 1960], No. 17958/62. Heading G2A A camera has a photo-electric exposure meter of which the pointer is explored by a sensing member, the sensing edge of which is so curved in a plane parallel to that of the pointer movement that engagement of the sensing edge with the pointer at equally spaced positions along the edge corresponds to progressive geometric changes in scene brightness. As shown in Fig. 1, the sensing member 28 is displaced upwardly under spring loading, when released by depression of button 60, until its sensing edge 29 engages the pointer 70 of photo-electric exposure meter 72. During such movement, the lower edges of recesses 76, 78 in two arms of the sensing member engage pins 80, 82 so as to adjust the shutter speed and diaphragm aperture respectively, the pin 82 being on the inner of two relatively rotatable rings to which the diaphragm blades are pivoted. The sensing edge 29 is formed in equal steps and is so curved in planes parallel to the plane of the pointer's movement as to compensate for non-logarithmic pointer response. In order to allow differential adjustments of the shutter speed and the diaphragm aperture, the pins 80, 82 are, in the modified form of Fig. 6, linked to opposite ends of a pivoted rocker arm 102 that moves linearly with the sensing member 90. The two pins are on arms 110 and 85 respectively and the movement of one of them is limited by engagement with pins 111, 113 on spring-loaded members 108, 109, rotatable about the lens axis. In the position shown, pin 111 prevents further adjustment of the shutter speed by movement of pin 80, but pin 82 is still free to adjust the diaphragm aperture in accordance with upward movement of the sensing member until the correct exposure value has been set. A pair of interlock plates 119, 121 are pin and slot connected and spring urged to move in opposite directions. When the stop member 109 is in its uppermost position, an ear 145 thereon pushes plate 119 so that a curved part 147 thereof will frictionally engage an ear 143 on stop member 108 and hold it in adjusted position until stop member 109 is moved downwardly. Film speed compensation is effected by movement of the meter 72, along a curved slot 174 parallel with the curve of the sensing edge 29, Fig. 3, to a new position by a pin 160 whenever a magazine containing film of different speed is loaded in the camera. For this purpose, each magazine has notch 152 in its upper surface, Fig. 9, this notch being positioned according to the film speed and being engaged by a lug 150 on a spring loaded plate 144 which is pivoted to a slidable plate 132 having a slot 158 in which the pin 160 rides, Figs. 1 and 3. Above the plate 132 is a spring loaded latch 118 for the pivoted camera back 114, Fig. 3. The back is released by moving latch 118 against its spring, and during such movement a lug 128 on the latch engages a pin 130 on plate 132 so as to move it. When the new magazine is loaded, the lug 150 on plate 132 engages the edge 153 of the magazine and, as latch 118 moves under action of its spring to lock the camera back 114, the plate 132 also moves under its spring loading until lug 150 enters the notch 152, such movement of the plate 132 re-positioning the meter 72 along curved slot 174. When flash photography is desired, the shutter housing 26 is rotated to register its index 182, Fig. 1,.with the symbol "FLASH", whereupon an ear engages the sensing member to prevent movement thereof on operation of the camera release and a window 181 uncovers the distance scale 185 on an indicator 179, which is coupled by a pin 178, Fig. 1, with the sliding plate 132 so that during adjustment of the camera for film speed a corresponding portion of the distance scale 185 is aligned with window 181. Moreover, movement of window 181 frees an arm 180 integral with the outer ring of the diaphragm, the inner ring of which is now held fixed by the prevention of movement of the sensing member. After such movement of the shutter housing 26, the lens focusing ring 24 is adjusted until the number on focus scale 194 opposite the foot 190 of the arm 180 is matched with the number opposite the arm 180 on distance scale 185. Arm 180 is then moved to the number on distance scale 185 corresponding to a selected subject distance, so as to set the diaphragm for this flash distance, the lens focusing ring 24 being simultaneously rotated by engagement of the foot 190 in one of several detents 192