Light rays which are reflected by any surface become polarized. Polarizing filters are used to select which light rays enter your camera lens. The Digital Circular Polarizing filter allows you to remove unwanted reflections from non-metallic surfaces such as water, glass etc. It also will 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. The PROMASTER Polarizing filter does not affect the overall color balance of a shot. Digital Anti-Reflection Multi Coating ? Specially formulated to pass light reflected off of a digital camera?s anti aliasing filter and silicon based CCD or CMOS sensor. Black Almite Frame and Black Rimmed Glass ? The black matte aluminum satin finish almite frame and black rimmed glass aid in reducing stray light and unwanted reflections. Low Profile Frame ? Ultra thin low profile frames prevent vignetting on super wide digital format lenses. Knurled Frame Edges ? Frames feature a knurled edge frame for easy attachment and removal.