While I have been very happy with my Epson 4990 and Silverfast (AI 6 Studio). They are amazing technology for the price. I am finding that a 16x20 print from a 4990 is acceptable but pushing the limits of what I consider acceptable resolution. This summer when I was teaching in Chicago I rescanned many negatives on an Imacon and got spoiled. I don't print large, rarely over 16x20, but the Imacon scans are clearly sharper at 16x20 and looked great even at 20x24. So, based on Ted Harris and Michael Mutmanski's recommendation (who's opinions are very informed and I value greatly), I have purchased a Microtek 1800f with SF AI6 Studio which I will start testing this weekend.
Any tricks to using this scanner with 4x5 b&w negs that I should know about?