hi, i can mistake here, so better ignor what i say, i think more info can be found about sensor 3320, if dpi sensor really have increment 250 dpi, 400dpi will use 500 in the real, but if you can confirm by subjective feeling is 400(not 250, and not 500), so i'm wrong with this assumption, other cause why better ifnore my comment, now absolutely - i, me, and my self can not feel different with increment 500 lol, i use 2000:)