The Hoya NXT Plus Circular Polarizer Filter allows the photographer to remove unwanted reflections from non-metallic surfaces such as water, glass, etc. A circular polarizer is a must-have filter for every photographer and Hoya's NXT Plus is a powerful upgrade to the best-selling NXT series. This filter applies a waterproof top coat to Hoya's polished smooth "clear" glass for maximum sharpness. There are two advantages to having a premium waterproof coating: (1) Water beads-up quickly, and easily slides off the surface of the filter for streak-free shooting. (2) It also makes the filter a lot easier to clean when dirt, water and smudges make their way onto the surface. Hoya applies 10 layers of patented anti-reflection (AR) HMC multi-coatings for improved contrast and color. The polarizing film is optical thin with a filter factor of 1.72 for faster AF and improved viewing over standard PL films. The knurled edges on the front of the filter make it easy to operate when attached to the lens. The NXT Plus CPL filter frames are precision-milled aluminum slim frame, making it lightweight and perfect for your super wide-angle lenses.What does a Polarizer do?Polarizers do one thing: remove reflections. Think sunglasses for your lenses. By removing reflections, you reveal the color, texture and detail beneath. So, leaves are greener, skies are bluer, and the beautiful rocks at the bottom of that secret mountain lake are revealed. Circular polarizers are also great for removing reflections from windows, painted surfaces, or just about any non-metallic surface. Depending on the lighting conditions, the effect can be dramatic or subtle, but it never hurts to pop it on and give it a try.Key Features:? Waterproof top-coat for easy cleaning? Hoya polished clear glass? 10-layers of HMC multi-coatings? 1.72 filter factor? Low-profile aluminum frame