| 摘要 |
PURPOSE:To stabilize a display of a focus state without damaging responsiveness of the display by providing the lower limit of a period of a focus detecting operation, and making a focus detecting period longer than the lower limit period by adding an additional time to a focus detecting time, when an integral time of an optical sensor array is shorter than its lower limit. CONSTITUTION:A CCD sensor 4 of a focus detecting circuit 2 receives a light of an object, its output is processed, a focus shift quantity signal xn from a defocus quantity arithmetic circuit 14 passes through an averaging circuit 26, and a sent focused state is decided by a deciding circuit 28 and displayed on a display means 34. On the other hand, from a timing circuit 18 of a CCD4, an integral time taun of the CCD is sent to an operating circuit 54, compared with the lower limit value tauo of an integral time from a constant storing circuit 52, a counter 56 counts a clock pulse by a time of DELTAtau=tauo-taun, and a counting end signal is sent to a controlling circuit 58. In case DELTAtau is ''0'' or negative, the operating circuit 54 sends the counting end signal, the counter 56 outputs the following detecting operation signal which is delayed by DELTAtau, from the controlling circuit 58, and the display is stabilized. |
