This is my first posting on this site so forgive me if I make a few mistakes.
After reading the article about the Canon 400 f 5.6 lens being much sharper then 100 to 400 IS lens at 400. If the lens quality different did not appear in previous Canon cameras both digital and film, and the film camera I am assuming you are using a high quality film, has the Canon 1Ds surpass the best regular film camera in quality. By reading article in my opnion would draw this concclusion that if I taken a photograph with the 1Ds at ISO 100 and the same photographwith the 1v with lets say Fuji Velvia film that 1Ds would produce a superior photograph. I wil take my opinion one step futher and say that Canon top of the line Digital Camera has or is going to reach the quality of a meduim format Camera very soon.