Haze(UV) filters are wise initial investments. They help protect your valuable investment from dust, moisture and scratches, which can lead to costly repairs. If desired they can be left on the lens at all times for protection. Haze filters provide additional benefits of correction for Ultraviolet(UV) light which can register on film and videotape as a bluish cast and can obscure distant details. Ultraviolet filters allow you to correct for the UV effect to varying degrees. UV-Haze filters are helpful when photographing mountain and marine scenes, where increased haze threatens to make your photographs indistinct in color and clarity. B&W slim filters are for wide-angle lenses and are 3mm thick. They do not have a front thread.