ND64...For much wider apertures or longer exposures... This ND 1.8 filter has a light transmission of 1.563% or a Filter Factor of 64x. Neutral Density filters will evenly reduce the amount of light passing thru the lens without effecting the color.
This ND64 filter reduce the amount of light entering the lens so much wider apertures can be selected, which is usefull where the light is too bright and is used for portraiture to reduce depth of field, and allows balancing of exposure to highlight a key subject.
Subject appears crisp and clear while the background becomes a soft blur. Also widely used for photographs of waterfalls and other nature scenes to emphasize movement, as the exposure is relativly longer. This filter also lets you use higher speed films in bright light.