| 摘要 |
PURPOSE: To execute a proper focusing action even when a power source for emitting light is consumed and the voltage thereof is lowered by controlling a signal correction means according to the voltage of the power source for emitting light by using a control means and switching a correction level. CONSTITUTION: This range-finding device is provided with a microprocessor(CPU) 5 and a battery check circuit(BC circuit) 15 is connected to the battery for a power source 9 of a camera. The BC circuit 15 is constituted of an A/D converter 16 converting the voltage value of the battery 9 to digital from analog and outputting it and a discrimination unit 17 discriminating whether the voltage of the battery 9 is lower than a prescribed level or not based on the output of the converter 16. By the CPU 5, a clamp circuit 12 is controlled and a clamp level is switched when it is confirmed based on the discriminated result of the discrimination unit 17 that the voltage of the battery 9 becomes equal to or under the prescribed level. Therefore, even when the battery 9 is consumed, the same power-ratio characteristic as a standard state can be shown. Besides, the proper focusing action can be executed even when the battery 9 is consumed. |
