This kit contains three Lee Neutral Density Filters, .3 (one stop), .6 (2 stops), and .9 (3stops).
Neutral Density filters offer the possibility to achieve otherwise unachievable results. ND filters appear gray and reduce the amount of light reaching the film. They have no effect on color balance. They enable the shooter 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 average situations.
Note:
Lee polyester filters are made from lightweight, optical polymeric materials
Neutral Density Filter Have Four Main Uses
To enable 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 which could cause overexposure
Neutral Density Factors
ND 0.3 (exposure adjustment = 1 stop)
ND 0.6 (exposure adjustment = 2 stops
ND 0.9 (exposure adjustment = 3 stops)