my little accident in Pembrokeshire, so now I can start looking for my trusty EF400mm f5.6L. In the mean time a friend and I have swapped lenses. He's borrowed my 70-20mm and I've had use of his 100-400mm. This weekend I took it to the local park with me, and I must say that I'm impressed with the results. It is sharper than I would expect a zoom to be, and the IS is very nice. A shame I can't compare the two lenses side by side.