Designed to adjust brightly reflected light especially sunlight (reflected off of water or glass) and reduce unwanted glare Creates dramatic sky/cloud contrast and saturates colours without changing colour balance Mount rotates to control amount of effect Coatings applied to both surfaces to suppress reflection and increase light transmission For use with autofocus cameras and lenses These filters offer both amateur and professional photographers HOYA's famous quality at reasonable prices. They have coatings applied to both surfaces to suppress reflection and increase light transmission. Light rays which are reflected become polarized. Polarizing filters are used to select which light rays enter your camera lens. They can remove unwanted reflections from non-metallic surfaces such as water or glass and also saturate colours providing better contrast. The effect can be seen through the viewfinder and changed by rotating the filter. The filter factor varies according to how the filter is rotated and its orientation to the sun. They also enable colors to become more saturated and appear clearer, with better contrast. This effect is often used to increase the contrast and saturation in blue skies and white clouds. HOYA's polarizing filters do not affect the overall colour balance of a shot.