This 4x4" Century Precision Optics ND Glass Filter enables you to adjust exposure without affecting color balance. Neutral density filters are available in 1, 2, 3, and more stops to suit individual situations.
Determining which neutral density filter yields ideal results for any given lighting situation takes knowledge, experience, and a collection of such filters. Choose the filter strength that adjusts the lighting to stay within the exposure latitude (greatest difference between bright/dark values) which still shows details in both of the digital or film medium in use.
Speaking generally, the 2-stop value (ND 0.6, the filter's clear portion, allows 4x more light to pass vs. darkest portion) 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 backgrounds
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 that could cause overexposure
Neutral Density Factors
ND 0.3 (exposure adjustment = 1 stop, reduces ISO 1/2)
ND 0.6 (exposure adjustment = 2 stops, reduces ISO 1/4)
ND 0.9 (exposure adjustment = 3 stops, reduces ISO 1/8)
UPC: 605228092747