The AFI II 7 back (33 mp) does quite well up to 100 ISO, and very nice at 200. Past that, there is some noticeable loss at 400. Colors are good, responsiveness decent, but not overwhelming. I don't think the image quality is that much better than the older 9 mu pixels (vs. the 6.6 mu ones used) in the older Phase backs, but you get a lot more resolution, which is very nice. It does holds highlights better. Very nice back overall.