The Circular Polarizer is the most popular special effect filter available. Polarizers can create deep blue skies, provide a general saturation to all colors, reduce glare, and minimize reflections. Screw-in Polarizers are featured with rotating mounts for precise control of polarization. The Circular Polarizer is designed for usage with both auto focus and non-auto focus cameras.
A circular polarizer has the same effect as a polarizer and is used on cameras with beam-splitting metering systems commonly found on autofocus SLRs.