The filters is substitute for Cokin P series, having a high quality. These filters gives great flexibility enabling you to position the filter exactly where you need it in your photo. You can find the differences from the above pictures that use with or without the filters. Gradual filter is a MUST HAVE for digital users, because the digital sensor unlike film has very low exposure tolerance. Detail will be lost on both low and high light area. To correct this, you need gradual filter to balance it!