Urth Hard Graduated ND8 Lens Filter (Plus+) The Hard Graduated ND8 (3-stop) Lens Filter Plus+ from Urth provides a fixed 3 f-stop light reduction for balanced exposure and better dynamic range in hard graduated light conditions. By blocking 3 f-stops of light from half your image, you can balance your exposure when the foreground is darker than the background - such as shooting landscapes in the mountains. The hard graduation creates a natural blending of light. Our Plus+ range features 20-layers of nano-coating providing easier cleaning and better protection against water, oil, and scratches. These layers also provide a higher maximum light transmission and a more consistent transmission curve for truer light reduction. The filter is double-threaded for stacking filters or using screw-mount lens caps. B270 Schott optical glass is coated with a 20-layer nano-coating for truer light transmittance, better protection, and easier cleaning. It gives a three f-stop light reduction to half your image to perfectly balance highlights and lowlights when shooting landscapes. Perfect exposure even when your foreground and background have different light levels. The consciously designed ultra-slim rim avoids vignetting and the durable magnalium is guaranteed for life.