Video Lighting Basics - Three Point Lighting

The key light is the main source of light in the shot which should be placed at 45 degrees to one side of the object, giving a person definition on the side of their face and shoulders, but this causes a sort of shadow on one side of the face which is filled in by the Fill light, which is placed at 45 degrees on the other side of the person and gives equal lighting to the whole object rather than just one side of it. The back light is placed around the back of the object but at an angle so its off camera, this gives more definition and clarity to the shoulders and outline of the object.