I have found that getting good focus and depth of field with the RB67 takes a little practice. I am pretty good with it now, but if I could change anything about the RB it would be finding some way of calculating focus distance more accurately on the lens, so that both hyperfocal focusing and precise depth of field control would be easier. Would it be possible to calculate the focusing distance for each lens based on the length of bellows extension? Has anyone tried this? Thanks!