The prond500 has a 9 stop light reduction equal to a nd optical density of 27 the accu nd technology in the hoya prond filters yields a truly neutral colour balance that will not add any noticeable colour cast to your images the hoya prond series is aimed at the still photography and hdslr video markets the series provides 9 filters from two stop to 10 stop light reduction the metallic accu nd coating on the prond filters do not colour shift as you move from one density to the