The Promaster Variable Neutral Density Filter (VND) provides from 2 to 9 stops of light reduction. Handles just like a polarizing filter. On a sunny day it can drop the shutter speed from 1/1,000 to 1/2 second. Or permit shooting with the lens aperture wide open for shallow Depth of field under any lighting condition.
Create dynamic images in creative ways. For example - In Manual mode the Variable ND filter allows the photographer to select a slower shutter speed and a specific aperture to achieve the desired Depth of Filed - for example 1/2 second and f/4.0 for motion blur and moderately shallow DOF. Once dialed in, simply turn the variable ND filter's ring until the camera's exposure meter zeros out. Use this technique to create images of sharply rendered subjects against motion-blurred backgrounds.