| 摘要 |
PURPOSE:To reduce a time for measuring a distance in response to a mode of photography by selecting reference voltage for ending distance measurement on the basis of output of a mode selection means and ending the distance measurement at the time when integral voltage has exceeded the reference voltage. CONSTITUTION:When a release switch 6 is pushed, CPU 80 confirms a photographing mode (normal photographing, serial photographing and quick release or the like) of a camera from a state of a mode switch 85, its corresponding voltage is set as reference voltage Vc, detection current 3 corresponding to the intensity of reflection light from an object to be photographed and an incident position thereof is input to current/voltage conversion circuits 20, 30, converted into voltage, amplification 40, 50 is performed and integration is carried out in an integrating circuit 60. Next, the voltage Vi from the circuit 60 is input to CPU 80, compared with the voltage Vc, when the voltage Vi exceeds the voltage Vc, distance measurement is ended and a distance up to the object to be photographed can be calculated. Since the voltage Vi is smaller the shorter a distance measurement time measured with the circuits 20, 30 is, the time from pushing of a switch 86 up to driving for a focussing position of a lens barrel 84 can be shortened and it has an advantage in fast photographing or the like. |
