The bw uv haze xs pro digital filter blocks the invisible uv component of light from the sky which can cause blur and to which many colour films react with a blue cast uv filters are ideal for photography in high altitudes by the sea and in regions with very clean air photographs gain brilliance and blue casts are avoided because the glass is colourless colour rendition is not altered and no increase in exposure is required that makes a uv filter suitable for protection of the lens again