Vimeo has a new section called “Vimeo Video School”. They have compiled a bunch of tutorial style videos for the beginner. In this “lesson” they describe three point lighting. This is fairly basic stuff but worth reviewing every once in a while. This video by LifeNow Video does a good job of explaining this process.
Key: This is the main light source. It shines directly on the subject, usually from the front-right or front-left. It provides the overall look and feel of the shot.
Fill: The fill provides balance to the key by filling in the rest of the subjects face with a softer light. It comes in from the front-side opposite the key light.
Back: The back light creates a nice rim of light around the back the subject, separating them from the background. It can also be called a “hairlight” or “rim-light”.
“Three-Point Lighting is the basic lighting setup to use when you want to get great looking shots of people you’re filming. It seems self-explanitory — you want to light the subject so you can easily see them, but using a 3-point lighting set up will make your subject look awesome and you’ll be instantly renowned as a professional.
Three-point lighting is exactly what it sounds like. You light your subject from three different sources in order to control the shadows and balance the contrast.”