Developed to exceed the sharpness needs of 50-megapixel cameras entering the market, the Hoya HD3 Circular Polarizer camera filter sports a new and improved 16-layer ultra-smooth, ultra-hard nano-coating that is 2x sharper and 200% harder than the award-winning HD2 Circular Polarizer. Combined with Hoyas exclusive High-Transparency polarizing film that allows 2/3rds of a stop more light transmission than standard circular polarizing films, the new HD3 Circular polarizer is faster, sharper, and Hoya Tough. Hoya engineers recognized a need for a circular polarizer filter that could meets the demands of super high resolution cameras, and the needs of photographers who shoot in conditions where every bit of light is important. Utilizing a new multi-coating process that applies 16-layers of anti-reflective coating to the optical UV glass, Hoya created a filter that is 2x sharper and a coating that is 200% harder than the award winning HD2 circular polarizer filter. This hardened coating is stain resistant and easy to clean when oil and smudges like fingerprints are introduced to the surface. Hoya selected a premium high transmission polarizing film that yields 40% greater light transmission than standard PL films. This translates to an additional 2/3rds of a stop of light passing through the filter for an overall 92% light transmission rate. Photographers now have more shutter-speed and aperture combinations to work with in those critical light conditions. The HD3 Polarizing glass is housed in a two-piece, lightweight, low-profile, aircraft grade aluminum filter frame. This two-piece design allows the filter to maintain perfect parallel alignment to the sensor plane for maximum sharpness and zero distortion. Knurled edges on both rings allow for easy rotation to achieve the desired The low-profile design eliminates the concern for vignetting when used on ultra-wide-angle lenses, and the front filter threads accepts lens caps and other filters for stacking.