>Lately I've been feeling the need for an ND grad, which sort of precludes the screw-on approach. The Cokin P system, at 84mm, seems big enough for most Pentax lenses except the really big glass and one of the 6x7 lenses that has a 100mm filter diameter. Singh-Ray seems to favor this size as well. <
if you use a ND gradient filter of any type, you cannot use a direct screw-on filter except in the most limited of circumstances. you have to go to a separate filter system with moveable filters. Cokin filters are prone to fading or color shifting, so be prepared to replace them periodically. other vendors should be more fade resistant. Herb....
