Neutral Density filters have four main uses

� 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 which could cause overexposure

Neutral Density Factors

� 2x = ND.3 (exposure adjustment = 1 stop, reduces ISO 1/2)

� 4x = ND.6 (exposure adjustment = 2 stops, reduces ISO 1/4)

� 8x = ND.9 (exposure adjustment = 3 stops, reduces ISO 1/8)

� As one of the premier filter manufacturers, Hoya filters continue to made from quality glass assuring the photographer clear, sharp and accurate images

� Hoya filters consistently provide even color all the way through the filter; All surfaces are ground and polished to specific thickness and tolerances

� Even non-multi-coated Hoya filters have one layer of anti-reflective coating applied to each surface of the glass; Hoya's single layer coating decreases light reflection off the surface from approx. 9% to an average of 4-5%