The invention is set at the condition where the aperture of monitor video camera is adjusted to the maximum and the shutter speed is adjusted to the minimum. Under the digital low speed shutter mode, the video camera saves the image frame captured in a certain period into the storage, and then combines the multi image frames saved in the storage to form a consecutive motion video, and finally output the monitor video. When the storage is full, the earliest image frame will be replaced by the one inputted in latest time. The invention can be used in very dark conditions, and keeps certain brightness in monitor video. |