ight rays which are reflected become polarized%2E Polarizing filters are used to select which light rays enter your camera lens%2E They can remove unwanted reflections from non%2Dmetallic surfaces such as water or glass and also saturate colors providing better contrast%2E The effect can be seen through the viewfinder and changed by rotating the filter%2E The filter factor varies according to how the filter is rotated and its orientation to the sun%2E Filter factor is between 2%2E3 and 2%2E8 %28approx%2E %2B1%2E3 stops%29%2E %0D%0A%3CP%3E%0D%0ACircular polarizers are specifically designed for use with auto%2Dfocus SLR cameras %28They will also work on manual systems and video cameras without problems%29%2E %0D%0AThis filter is a must for all outdoor sunny or snowy high glare situations%2E It will cut out the extra bright glare and allow you to get the true blue colors%2C not washed out%2E Most photographers view this filter as %22sunglasses%22 for your camera lens%2E%0D%0A%3CP%3E%0D%0ACircular Polarizing Filters are used to increase color saturation%2C like darkening blue skies so that white clouds stand out%2E It eliminates reflections from non%2Dmetallic surfaces like glass and water%2E It helps reduce softness in scenery caused by atmospheric haze%2E This filter will not change the overall color balance of a photograph%2E %0D%0A%3CP%3E%0D%0APolarizers are commonly used to control glare on water and to allow the camera to see below the surface%2E They are also used to reduce glare on car bumpers and to control reflections on plate%2Dglass windows%2E Polarizers are so versatile that they can perform the opposite functions as well%2E Some cinematographers use polarizers to increase or enhance reflections%2C simply by changing the filter%92s setting%2E %22Circular%22 refers not to the shape%2C but a special design that does not interfere with metering of auto exposure or auto focus systems