The 2x Neutral Density 0.3 Filter has several uses and offer 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 either the sensor of a digital camera or the film plane of a traditional film camera. Neutral Density filters are used to create some unusual special effects such as capturing the "blur" of the rippling water of a waterfall or the swirling effect of city traffic.
Glass is produced through a process that entails permanently laminating the filter material in between two pieces of optical glass that are ground flat to tolerances of a ten-thousandth of an inch, then mounting them in precision aluminum rings. Determining which neutral density filter yields ideal results for any given lighting situation takes knowledge, experience and a collection of such filters.
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