A skylight filter is similar to a UV and is clear and great to help protect the lens far better to scratch the filter than the lens.. They also perform several other functions. They absorb Ultra violet light, a major cause of haze and excessive bluishness, but unlike UV filters they are slightly pink and come in different densities I leave one on all my lenses or the UV

Danny O'Byrne  http://www.digitalartzone.co.uk/

"All the technique in the world doesn't compensate for the inability to notice" Eliott Erwitt