slick 49mm UV Filter for Nikon, Canon, DSLR. Digital Cameras need special filters. Filters eliminate the flare and ghosting prevalent when the CCD or CMOS chips in digital cameras convert light into electrical signals. Films and CCDs behind camera lens are sensitive to ultra-violet rays (UV rays). UV rays are invisible to our eyes but when they are recorded on the CCD, the image might look bluish and the colour casts might thus be distorted. Excessive bluishness frequently occurs in outdoor photography especially in open shade under a clear, blue sky and near water front while haze is caused mostly by dust particles in the air. When daylight shines through the sky, the particles reflect the short wavelengths of the light more than the long one. This UV filter effectively helps eliminating the lack of sharpness, absorbing UV that causes blue cast, as well as reducing distant haze that caused by UV radiation. It also protects your camera lens from dust and scratch.