Vnd EffectThe Haida Proii Variable Neutral Density Filter is a variable neutral density filter that provides an exposure reduction of 1.5 to 5 stops. The 1.5 to 5 stops creates a darkening of the entire image, allowing you to photograph with a wider aperture or slower shutter speed than normally required. The degree of density is easily controlled by rotating the filter ring, helping you to predetermine the additional exposure length required.CoatingThis Proii Vnd filter is constructed from optical glass for clarity as well as color fidelity. To prevent internal ghosting and reflections, the glass features eight layers of multi-coating. These coatings also offer greater protection to a filter substrate and help it to stay clean for longer than with uncoated filters.FrameUltra slim an aluminum alloy ring ensures durability while allowing the filter to remain lightweight. The thin, aluminum-alloy filter ring minimizes the potential for vignetting, while remaining durable and lightweight..