K&F 40.5mm ND2 to ND400 Variable Neutral Density Lens Filter

The K & F 40.5mm ND2 to ND400 Variable Neutral Density ND Filter enables slow shutter speeds to be used to record movement in subjects such as waterfalls, providing a silky-smooth affect to flowing water. Reduces the amount of light entering the lens, thus decreasing camera shutter speed. Useful for situations where motion blur needs to be created (rivers, waterfalls, moving people) or large apertures must be used with flash to avoid overexposure.