As many of us are aware, the sunlit sky fills our atmosphere with all sorts of radiation. We know that UV (Ultraviolet) and IR (Infra-Red) may cause sunburn. Yet the human eye does not have the ability to distinguish these levels of light. Film, however, is sensitive to several of these and they can effect the resulting photo. For the most part, UV rays may appear as a bluish haze. This filter is designed to help eliminate most of these skylight rays to help assure clearer and sharper images.