Hoya 77mm Circular Polarizer Glass Filter: The Light rays which are reflected by any surface become polarized and Hoya 77mm Filter are used to select which light rays enter your camera lens. Hoya 77mm Circular Polarizer Filter allow you to remove unwanted reflections from non-metallic surfaces such as water glass. Hoya 77mm Glass Filter also saturate colours and increase contrast. Hoya 77mm Filter come in two variations but have the same effect. Linear polarizer work with older camera meters, Circulars polarizer are designed for today's newer split-beam metering systems used in auto focus cameras. Check your camera's manual.