| 摘要 |
PURPOSE:To appropriately set the frequency for detecting a focal point in response to the brightness of an object by switching the frequency that a focal point detecting means detects a focal point in response to the brightness of an object. CONSTITUTION:When the frequency for detecting a focal point is short, the focal point detecting means 1 cannot secure a sufficient charge accumulating period, because it includes a charge accumulating type image sensor; therefore it is difficult that the means 1 detects a focal point of the object with a low brightness. On the other hand, when said frequency is long, the means can detect a focal point even when the brightness of the object is low, however, it takes a longer time to decide a moving body. Accordingly, when the brightness of the object is low, focal point detecting frequency switching means 4 prolongs the frequency for detecting a focal point. Conversely, when said brightness is high, the switching means 4 shortens the frequency of detecting a focal point. As a result, a focal point can be detected, time required for deciding a moving body is shortened, and the responsiveness of following up the movement of an object can be improved. |
