| 摘要 |
PURPOSE:To provide a variable system clock type digital electronic still camera which can reduce the noises of quantization caused by the A/D conversion and the signal interference caused between the sensors and then can ensure the high picture quality even at a low illuminance by securing such a circuit constitution that can reduce the clock frequency or can increase the clock cycle even at a low illuminance of an object. CONSTITUTION:The image of an object is inputted to a signal processing circuit 8 via an image pickup system, a CDS circuit 5, an A/D converter 7, etc. A system control CPU 13 decides whether the object has a low illuminance or not according to a fact whether the level of the luminance signal supplied from the circuit 8 is higher than a prescribed level or not. If a low illuminance is confirmed, the system clock outputted from a synchronizing signal/timing signal generating circuit 11 is controlled so that the system clock has the frequency lower than that of an NTSC system. Furthermore a CCD driving circuit 10, the converter 7, and the driving circuit of a liquid crystal display 17 can operate in a normal way in response to the system clock of the low frequency. |
