The Tiffen Soft Edge Graduated 0.9 ND 4 x 4" filter is a graduated neutral density filter that helps to specifically darken skies and other bright areas of the image. The filter is densest at the edge and gradually clears towards the middle, with a soft transition line between the dense and clear areas. Neutral density filters do not affect the colouration of the image and the 0.9 density provides a 3-stop reduction of light entering the lens.nnThis filter is made using ColorCore technology, a process that involves laminating the filter substrate between 2 pieces of optical glass and grinding it flat to a tolerance of 1/10,000th of an inch. This filter measures 4 x 4" / 101.6 x 101.6 mm.nnnFeatures:nn- 0.9 ND graduated filter with soft edge to darken skies and other bright areas of the image.n- Provides 3-stop light reduction in selected areas.n- Neutral density filters do not affect the overall colouration of the image.nnnSpecifications:nn- Filter type: Graduated neutral densityn- Size: 4 x 4" / 101.6 x 101.6 mmn- Filter factor: 0.9 (3 stops)