ND filters work especially well for portraits by allowing the photographer to reduce the depth of field, producing pleasant background blur while keeping the subject in sharp focus. These filters are also often used to emphasize movement by permitting slow shutter speeds in bright light, giving life to photos that would otherwise look frozen in time.

This particular filter (HMC) is multi-coated to minimize reflection on the filter surface, which reduces flare and ghosting, and produces sharp contrast and well-balanced color. An ND4 filter reduces the amount of light by 2 stops.