Hoya HD3 Circular Polarizer Filter The Hoya HD3 Circular PolarizerFilter uses chemically-hardened high-transparency optical glassto boost color saturation, clarity, and contrast without affectingoverall color balance of your image. It reduces background haze byremoving unwanted reflections and glare from non-metallic surfaces likeglass or water, allowing for clearer photographs of the sky andfoliage. By using a circular polarizeras opposed to a linearpolarizeryou gain a quarter wave plane that prevents any loss ofusability of your cameras autofocus and exposure functions. The HD3filter contains 16 layers (8 on each side) of tough anti-reflectionNano coating that is water, stain, and scratch-resistant and easy toclean. Hoyas HD3 filters provide over 92% light transmission for truercolors.