

The key light is the primary light used to illuminate a subject. It is usually positioned 15 – 45 degrees from one side of the camera and angled down 15 – 45 degrees from above the subject. This light represents the primary source of light in a scene simulating the sun, a window, a light bulb or some other source of light.
After the key light is positioned you will notice a harsh shadow on one side of the subject opposite the key light. The fill light is meant to reduce the shadow but not eliminate it entirely (shadow gives a sense of depth). A fill light should be placed on the opposite side of the key light but needs to be about half as bright and not positioned quite as high. Do not place it at the exact same angle as the key light. It is meant to simulate other light sources or light that is being reflected off other objects.
The back light needs to be placed behind the subject opposite the camera but high above both so that none of the light goes directly into the camera. This light will create a slight glow on the back of the subject and thus separate it from the background. This prevents the subject from looking two dimensional on the film. It is sometimes referred to as the hallo effect.
http://www.youtube.com/watch?v=3far9oHZOsI
This video uses very quick flashing view points - extreme close ups, mid shots, long shots. The overall feeling of this video is unnerving, it creates a strange enigma as to what you are watching, and the viewpoints change frequently to keep it very chaotic and mysterious. Chris Cunningham follows similar themes, colour pallets and unusual moving imagery throughout his work which makes him stand out from other directors...his work is memorable and almost addictive to me...I constantly want to see new videos! Chris Cunningham is one of my all time favourite directors and video artists!!!