| 摘要 |
PURPOSE:To effect the automatic focal adjustment without any error by controlling the detection of a focal point and the movement of an objective lens system in a time shearing manner. CONSTITUTION:The digital signals l and m of the degrees of being out of focus from the front and rear focal points of a camera lens are counted by a counter U2 or U3 to light one of LEDL1 to L9.For example, in the case of the rear focal point, the number of pulses stored by the counter U2 is fed to the down terminal of the counter U2 by manually moving an objective lens. As a result, the LED L5 is lit by ORs2 to 4 so as to indicate the condition of being in focus. When a switch S3 is shifted to its q side, a transistor Q3 is rendered conductive through AND3 and AND4 so that an LEDL10 indicates the condition of being in focus at a rear focal point. At the same time, transistors Q10, Q13 and Q15 are rendered conductive so that the objective lens is driven by a motor. The pulses according to the movement of the motor are fed to the down terminal of the counter U2 so that the LEDL11 is lit to indicate the condition of being in focus by OR2 and AND3. |
