Hi Folks! (Posted this in the Technical forum but thought this may one may have more...errr...focus....) I've just got back from an AMAZING trip to the SW USA (Colorado, Utah & Arizona), but I've stumbled across a few issues..... I was in Zion NP and came across some shots that I could use my Singh Ray Variable ND filter on to get that "soft water" look. So I had my D70, 17-55 with a Hoya UV filter and the ND on the front. Most of the shots I got had a strange magenta cast across them: And a few had a strange black area on the frame which looks like the half-and-half issue reported in an earlier thread: Any thoughts as to why this happens? I'm confused..... The EXIF can be seen in this gallery..... Thanks in advance!