The CCD (charge-coupled device) is the part of the camcorder that captures the light and turns it into video information. The CCD is one of the most important factors to video quality. A low quality CCD can cause problems such as noise, overexposure, blurred video, and artifacts.
CCDs are also used in things like digital cameras and webcams. A CCD designed for a camcorder will be different than a CCD for a digital camera, so even the best camcorders will not be able to produce more than decent results for still pictures.
Most camcorders have a pattern of color filters to capture color. Some more expensive camcorders have three CCDs, one for each of the primary colors of light (Red, Green, Blue), which are then used by the imaging chip to produce a higher quality video.