CCDs (see above), have to approximate the 16:9 ratio using a number of tricks developed by the manufacturers.
LCDs and Viewfinders
LCDs and viewfinders are mechanisms used for playback on the camcorder itself. While almost all consumer camcorders can be plugged into a television for playback, the LCD and viewfinder offer immediate playback of media. Generally, the more pixels on the LCD or viewfinder the better; pixel are given in thousands, such as 123K (123,000 pixels). LCDs and viewfinder size is measured on the diagonal. A 2.5-inch LCD screen will have sides smaller than 2.5 inches.
Focus
An image is in focus when it is crisp and clear to the viewer. Put another was, a focused image occupies the focal point of a lens mechanism. The focal point of a lens system is the point at which all refracting or reflecting light rays from the lens converge,