The 77mm True-Match Vari-ND MKII Variable ND Filter from Schneider is a solid variable neutral density filter with an adjustable filter factor of 0.45 to 3.45 that provides a reduction of 1.5 to 11.5 stops. This 77mm filter darkens the entire image area, allowing for wider apertures or longer shutter speeds than usually required. The variable density is easily controlled by rotating the front filter ring, allowing the additional required exposure length to be determined. By slowing the exposure time, the level of image blur and sense of movement may be enhanced, and by adjusting the lens aperture, the depth of field may be more precisely controlled. This is especially useful when shooting images in bright sunlight, where achieving long shutter speeds and wide apertures is otherwise impossible.
The variable neutral density effect is achieved by stacking highly neutral gray polarizing filters within a filter cell and rotating them to block the desired amount of light. Despite its double-frame structure, the True-Match Vari-ND MKII features a 5.9mm slim profile, which prevents vignetting with most wide-angle lenses.