Polarizers provide color and contrast enhancement. Reflected light often shows up as whitish glare that washes out color in an image. A Polarizer corrects this problem producing deep, dramatically blue skies. It also removes glare from non-metallic surfaces, such as windows and water. Color saturation in general, especially outdoors, can be improved significantly.
Essential general-use outdoor color filter
Produces deeper skies and minimizes reflections in black and white and color photography
Combine a Polarizer with a Red 25 for incredibly dramatic black and white landscapes
Can be rotated to achieve desired effect
Use the Tiffen Polarizer with the enhancing filter for more dramatic effects
Available for Wide Angle lenses
A Circular Polarizer has the same effect as a Polarizer and is used on cameras with beam splitting metering systems commonly found on auto focus SLR's (for most 35mm auto-focus cameras see your camera manual).
Area of sky most effectively polarized with a Circular Polarizer:
Point your index finger at the sun. With your thumb extended at a right angle (90?), rotate it around the axis of the index finger. It will point out the band of deepest blue from horizon to horizon.