Key Light; Shines directly upon the subject and is the main illuminator. This light gives the subject the strength, the colour and angle of the key.
Fill Light; Also shines upon the subject but from a side angle and is often placed in a lower postition than the key light. This light illuminates the shaded surfaces.
Back Light; Shines on the subject from behind; thus giving the subject the rim of light; highlighting contours and separating the background.
Tracking
This is where a camera is mounted upon a camera dolly; which can be wheel based or based upon two rails. Tracking shots can be used to film smooth movements forward, backward and also along the side of a subject. Some tracking dollies also have hydraulic arms which can track on a vertical axis.
