The Tiffen 49mm Digital ND Filter Kit is a complete set of filters to help you get better shots in bright light as well as assist you with some special effect images. Neutral density filters have several uses and offer the possibility to achieve otherwise unachievable results. They enable the photographer to adjust exposure without affecting color balance. ND filters appear gray and reduce the amount of light reaching the film. Determining which neutral density filter yields ideal results for any given lighting situation takes knowledge, experience, and a collection of such filters. Speaking generally, the 2-stop value (ND 0.6) effectively compensates for average situations. Each filter is made of high-quality ColorCore glass and has a black aluminum filter ring. Neutral Density Filters have Four Main Uses The Tiffen 49mm Digital ND filter enables slow shutter speeds to be used, especially with high-speed films, to record movement in subjects such as waterfalls, clouds, or cars. To decrease depth of field by allowing wider apertures to be used, which helps separate subjects from their background. To decrease the effective ISO of high-speed film (above ISO 400) and allow it to be used outdoors in bright situations. To allow cine and video cameras (which have fixed shutter speeds) to film subjects such as snow, sand, or other bright scenes that could cause overexposure. The filter kit comes with ND.6 (exposure adjustment of 2 stops, reduces ISO by 1/4), ND.9 (exposure adjustment of 3 stops, reduces ISO by 1/8), and ND1.2 (exposure adjustment of 4 stops, reduces ISO by 1/16) filters. The filters are all made in the USA.