| 摘要 |
PURPOSE:To execute an exposure control with an extremely high accuracy by detecting a speed of a shutter which is being operated, obtaining the information related to an actual shutter aperture, and controlling an exposure time. CONSTITUTION:After an output (shutter opening time) S4 of a counter 88 and an output (instantaneous diaphragm value) S7 of a counter 14 are inputted, an arithmetic circuit 5 retrieves a reference opening time S8 corresponding to the detected diaphragm value S7 from a ROM 4, and thereafter, calculates a value (x) which is divided S4 by S8. Subsequently, a field luminance S5 is inputted from an A/D converter 3, and thereafter, an exposure time S6 corresponding to the field luminance of the reference opening time, etc. is inputted from the ROM 4, an exposure correction time (y) is obtained by an operation of (y) = (x) X S6, and it is outputted to a preset counter 6. Accordingly, as for the preset counter 6, a signal level of its -Q terminal goes to H, when the time (y) has elapsed, an AND gate 20 goes to non-conducting and a transistor 23 is turned off, an electromagnet 22 is demagnetized and the shutter is closed by a spring.
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