I've used both and found the 100mm slightly sharper and so I sold the 80mm. BUT, for my enlarger the 100mm isn't wide enough for 16x20, so I bought a Rodenstock APO 80/4 (Non-N) and love it. Super sharp. I recommend an 80mm APO lens if you're enlarging to 20x24. They're rather cheap now. I got mine for $200.