The B+W UV-Haze XS-PRO Digital Filter blocks the invisible UV component of light from the sky, which can cause blur & to which many colour films react with a blue cast. UV Filters are ideal for photography in high altitudes, by the sea & in regions with very clean air. Photographs gain brilliance & blue casts are avoided. Because the glass is colourless, colour rendition is not altered & no increase in exposure is required. That makes a UV Filter suitable for protection of the lens against dust, flying s&, sea water spray & the like, & it can be kept on the lens at all times. It is recommended for analogue colour & black-&-white as well as digital photography.