The Formatt-Hitech 4 x 5.65" 0.9 Soft Edge Graduated Neutral Density Glass Filter specifically helps darken skies and other bright areas of the image. The filter is denser at the edge and fades towards the centre, with a soft transition line between the dense and clear areas. By having only a portion of neutral density on the filter, you can selectively darken areas of an image whilst allowing the part of the image in the clear section to receive normal exposure. Neutral density filters do not affect image colouration and the 0.9 density provides a 3-stop reduction of light entering the lens. Formatt-Hitech glass filters are manufactured from high-quality Schott Superwite glass for exceptional clarity and maintained light transmission. This filter is compatible with the Formatt Hitech 100mm filter holder and measures 4 x 5.65" / 101.6 x 143.5mm. The horizontal orientation designation means that the transition line of this filter is parallel to the long side of the filter. - 0.9 soft edge graduated ND filter to darken skies and other bright areas of the image. - Provides a 3-stop light reduction in selective areas. - The soft edge transition is ideal for circumstances where there is no distinct separation line between bright and dark areas of the image. - Neutral density filters do not affect the overall colouration of the image. - Compatible for use with the Formatt Hitech 100mm filter holder.