The Singh-Ray Daryl Benson Reverse Neutral Density Graduated Filter for Cokin P is a unique and very effective way to control the balance of your foreground and an ultra-bright horizon line. This filter is designed to maintain control, i.e. hold back, the brightness of an excessively bright horizon area while allowing for more detail to be captured in the sky and foreground.
Often it is necessary or desirable to balance the light intensity in one part of a scene with another. This is especially true in situations where you don't have total light control, as in bright contrasty landscapes. Exposing for the foreground will produce a washed-out, over-exposed sky while exposing for the sky will leave the foreground dark and under-exposed. This filter enables cloud detail to be kept correctly exposed in the picture.
Determining which graduated neutral density filter yields ideal results for any given lighting situation takes knowledge, experience and a collection of such filters. Choose the filter strength which adjusts the lighting to stay within the exposure latitude (greatest difference between bright/dark values) which still shows details in both of the digital or film medium in use.
Speaking generally, the 2-stop value (ND 0.6 - the filter's clear portion allows 4x more light to pass vs. darkest portion) effectively compensates average bright sky-to-foreground situations, and the soft transition is applicable more often to a scene than the hard transition.