My LF negatives with Lee IR filter, MACO 820c and a Zeiss Planar 135mm at f:3.5 were sharpest without any correction. I tried both no correction and advancing 1.5mm. Same with a 210mm Xenar at f:4.5 and a 360mm Tele-Xenar at f:5.5. These lenses should be different enough to be representative of a large number of fairly simple lenses.