The Singh-Ray 150 x 150mm Galen Rowell 0.9 Soft-Edge Graduated Neutral Density Filter helps to specifically darken skies and other bright areas of the image. The filter is densest at the edge and tapers to clear by the middle, with a soft-edged transition line between the density and clear areas. By having only a portion of neutral density on the filter, you can selectively darken areas of an image while allowing the portion of the image within the clear section to receive the normal amount of exposure. Neutral density filters do not affect the coloration of the image and the 0.9 density provides a 3 stop reduction in light from entering the lens.
Singh-Ray rectangular filters are constructed from CR-39 optical resin for high image clarity and overall durability. This filter measures 5.9 x 5.9" / 150 x 150mm.