Watching film is an audio and visual. But many times sound is given less importance than video. It is important to remember that sound is the second dimension that brings your production alive.
Good sound starts with a good microphone.
The microphones on many DV video cameras are decent, but they come with a few inherent limitations. For one, the microphone is fixed to the camera so the microphone can only be where the camera is. This problem is magnified when the subject you are shooting is not close to the camera and there is a lot of external noises. Another problem that results is camera noise. When the audio level is low, the automatic gain control built into most DV video cameras will compensate.