Neutral Density Filters Have Four Main Uses

To enable slow shutter speeds to be used, especially with high speed ISOs, 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 situation To allow cine and video cameras (which have fixed shutter speeds) to film subjects such as snow, sand or other bright scenes which could cause overexposure ColorCore Technology The ColorCore process allows Tiffen to control the color and density of their filters, and the characteristics of special effects filters with much greater accuracy than typical dyed-in-the-mass filters, which usually exhibit color and density variations. In this way, Tiffen can better control the various densities of their filters and thereby create more exact degrees of filtration Tiffen, a leader in the filter industry, proudly makes its filters in the USA and backs up its products with a solid 10-year warranty