This kit contains three Lee Neutral Density gels: .3 (one stop), .6 (2 stops), and .9 (3stops). This set also contains the Lee Gel Snap. The Gel Snap is Lee's easy and affordable filter holder. Simply insert your 4 x 4" filter, snap it shut, and "snap" it on to any lens 82mm or smaller using the included "Elastomeric Tension Device", also known as an "E.T.D.", i.e, rubber band.
Neutral Density filters offer the possibility to achieve otherwise unachievable results. ND filters appear grey and reduce the amount of light reaching the film. They have no effect on color balance. They have four main uses: 1) To enable slow shutter speeds to be used, especially with high speed films, to record movement in subjects such as waterfalls, clouds, or cars. 2) To decrease depth of field by allowing wider apertures to be used, which helps separate subjects from their background. 3) To decrease the effective ISO of high speed film (above ISO 400) and allow it to be used outdoors in bright situations. 4) 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.
Lee polyester filters are made from lightweight, optical polymeric materials.
Neutral Density factors:
ND .30 (exposure adjustment = 1 stop)
ND .60 (exposure adjustment = 2 stops)
ND .90 (exposure adjustment = 3 stops)