| 摘要 |
1,093,235. Photo-electric control of camera. exposure. PRONTOR-WERK ALFRED GAUTHIER G. m.b. H. Dec. 17, 1965 [Dec. 28, 1964), No. 53674/65. Heading G2A. A photographic camera is provided with one or two photo-electric cells for automatically controlling the settings of diaphragm and exposure time, and with two electronic circuits, the first for controlling the diaphragm setting and the second for controlling the exposure time setting, the circuits being arranged so that the diaphragm is wholly or partially set before the second circuit begins to function. The camera has provision for manual over-ride of the automatic setting mechanisms. In the diaphragm and shutter arrangement shown, depressing the camera release 6 when making an automatic exposure, causes the diaphragm setting member 1 to rotate clockwise (Fig. 1), thereby closing a switch 5, which causes an electromagnet 27 (Fig. 3) to be energized, thus locking a lever 35 in the position shown. Rotation of the member 1 also drives a cut-off device 8-9 to progressively lower the resistance of a photoelectric cell. When the operating valve, previously set through a programme (30), Fig. 5 (not shown), is finally reached, transistors (T 1 , T 2 ) conduct to energize an electromagnet 23, thereby -causing a lever 25 to engage a tooth 1c to set the diaphragm according to the prevailing light conditions. Further depression of the member 6 rotates a lever 17 allowing the shutter blade ring 13 to rotate. This movement closes switches S 2, S 3 which in turn close a circuit to connect the cell 7 to the exposure time generating circuit, and opens a switch S 4 which in turn causes a capacitor (c) (Fig. 5) to charge. When the shutter is fully open, its driving disc 14 is held by the lever 35 until the capacitor (c) is fully charged, when, through transistors (T 3 , T 4 ), the electromagnet 27 is de-energized and the lever 35 is free to be moved by the disc 14, which rotates further to close the shutter. In another embodiment Figs. 8-10 (not shown), separate photo-electric cells (45, 46) are provided, one for each control circuit. A scale (52) Fig. 11 (not shown) and pointers may be provided in the viewfinder to show the generated diaphragm and exposure time values. |
