Why Use a Polarizer? Think of a polarizing filter as sunglasses for your camera. What does a circular polarizing filter do? What is the difference between a circular and linear polarizer? Along with UV and ND filters, Polarizing filters are among the essential digital SLR camera filters that every photographer should have this filter guide will explain it all. Polarizing filters provide color and contrast enhancement. Reflected light often appears as a whitish glare that washes out color from an image. A polarizing filter corrects this problem producing deep, dramatically blue skies. It also eliminates glare from non-metallic surfaces such as windows and water. Overall color saturation, especially outdoors, can be significantly improved through the use of polarizing filters. Extra hard and durable anti-reflective and transmission coating deepens blue skies enhances clouds minimizes reflections. High quality ColorCore glass made in the USA. Can be rotated to achieve the desired effect. Point your index finger at the sun. With your thumb extended at a right angle (90 degrees), rotate it around the axis of your index finger. You will be pointing to the band of deepest blue from horizon to horizon.