The Hoya 55mm HD UV Filter is a general use, clear filter designed to absorb ultraviolet light and reduce the bluish cast of daylight. Aside from the reduction of unwanted blue casts, no additional coloration or contrast is created, and adjustments to exposure are not required while using this filter. To prevent internal ghosting and reflections while providing over 99.35% light transmission, eight layers of anti-reflection coatings are applied to both sides of the glass for a total of 16 layers of coating. These coatings offer a high degree of protection to the filter substrate and helps it to stay clean for longer than uncoated filters. The coating formula associated with HD UV filters also promotes effective cleaning with regard to water, oil, and stains. Constructed from chemically-hardened optical glass, the Hoya 55mm HD UV Filter offers enhanced resistance to scratches while providing clarity and color fidelity. It also features a thin, lightweight, aluminum-alloy filter ring to minimize the potential for vignetting. This UV filter is also useful as a general protective filter to leave on lenses at all times. Such filters help to reduce dust and moisture from reaching your front lens element and provide additional protection in case of drops or situations where scratching could occur.