The Hitech 85 x 110mm ND 0.9 Soft Reverse Graduated Filter is unique compared to other graduated neutral density filters in that the density begins in the middle of the filter and tapers off toward the edge of the filter. The soft-edged, 0.9 density is placed in the middle of the filter in order to help compensate for bright horizons or other circumstances when the brightest part of the image is located in the middle of the frame. Normal graduated ND filters are unable to achieve similar results due to the physical edge of the filter lying within the picture plane while photographing in a similar manner.
This filter measures 3.35 x 4.33" / 85 x 110mm and is compatible with the Cokin P filter holder. The 0.9 density provides a 3 stop reduction in light from entering the lens.
Reverse graduated filters place the most density in the middle of the filter to accommodate bright horizons and other situations where the brightest part of the image lies in the middle of the composition.
Soft-edged 0.9 density tapers off without a hard, direct line from the center to the edge.