| 摘要 |
The present invention relates to an automatic focusing apparatus provides an automatic focusing operation free from the effect of light illuminating an object and which operates in a short period of time and with a high reliability. The automatic focusing apparatus includes a focus lens, an image-sensing circuit, a focus motor, a focus evaluating value generating circuit, a focus motor control circuit for intermittently driving focus motor at a timing synchronized with a field cycle, a first subtractor for detecting change in the focus evaluating value during a prescribed time period T1 when focus motor is stopped, and a second subtractor for detecting change in the focus evaluating value during a prescribed time period T2 before and after the movement of focus motor. The focus motor control circuit compares the detection outputs of subtractors and reverses the rotation direction of focus motor if the output of first subtractor is larger than that of the second substractor, and maintains the rotation direction of focus motor if the output of subtractor is smaller than that of the second substractor, while repeating intermittent driving of focus motor.
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