A colourless UV filter absorbing ultraviolet rays which cause excessive blue at altitude or when photographing by water, as well as cutting haze for black and white photography. Recommended for use also as a protective filter. HMC (Hoya Multicoated Coating) protective coatings on both surfaces give enhanced light transmission (97%) and so reduce glare and ghosting. Slimmer 4mm mount avoids vignetting occurring with all but extreme wide-angle lenses.