The Rodenstock S has a greater image circle than the N version. I've seen transparencies taken on both and I couldn't see any difference in image quality - but if you want big movements then the S is the answer. If you don't need this (major movements) then the 150 Apo Symmar is awesome! But the best kept secret......the Fuji 150! What a sharp lens! With plenty of coverage and small in size! You may be interested to know that Robert White in the UK has a good sized inventory of Fuji lenses (demo stock) at CHEAP prices!!