I had a demo of the Microtek 2500 and 1800f last week. The opening in the 4X5 holder for the 2500f was so large that Velvia from Quickloads would fall through it. The 1800 they brought out to demo was defective and produced posterized looking blocky areas in the shadows. I'd appreciate a little feedback from 1800f owners. Does this scanner produce clean shadow areas without multi-sample scanning? Does the film holder work with film from Quickloads without having to tape them in place? - Thanks!