This filter provides a convenient way adjust exposure control by varying the amount of light entering the camera by 1.5 to 9-stops (equivalent to NDx3-400 or 0.45-2.7 density). The precision double-ring design allows the outer ring to rotate, controlling the amount of neutral density anywhere within the 1.5 to 9-stop range. The thin double-ring design also reduces the likelihood of vignetting with wide-angle lenses. This versatile filter allows for many special effects such as being able to control depth of field by using a wider aperture or create or control motion blur by being able to choose slow shutter speeds for perfect blurring.

Features:
 
Reduces shutter speed for motion blurring effects (water, people, vehicles etc.)
Allows wider apertures to be used to decrease depth-of-field
Allows video/cine cameras, with limited shutter-speed range, to film in bright lighting conditions
For best results with slow shutter speeds, always use a tripod!
Available in sizes from 52mm to 82mm diameter