The Cavision 5.65 x 5.65" Graduated Neutral Density (ND) 1.2 Filter has several uses and offers the possibility to achieve otherwise unachievable results. It enables the shooter to adjust exposure without affecting color balance. ND filters appear gray and reduce the amount of light reaching the film.
Exposing for the foreground will produce a washed-out, over-exposed sky while exposing for the sky will leave the foreground dark and under-exposed. Graduated Neutral Density filters are part clear, part neutral density. They allow the transition to be blended into the scene, often imperceptibly.
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.
Neutral Density Filters 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 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
Neutral Density Factors
- ND.3 (exposure adjustment = 1 stop, reduces ISO by 1/2)
- ND.6 (exposure adjustment = 2 stops, reduces ISO by 1/4)
- ND.9 (exposure adjustment = 3 stops, reduces ISO by 1/8)
- ND1.2 (exposure adjustment = 4 stops, reduces ISO by 1/16)