I've been shooting for quite a long time and have the older Canon 1.4 tele-extender. I mostly use it with my 70-200L f4 is and my older 300 f4(a very sharp lense on a tripod). I shoot a 50D and XSi and have seen no image degradation or information problems that I can discern. But I have been told that version II is a must with the newer lenses, like the 70-200. Am I missing something? Or is there just a different inside lens barrel coating to cut down on ghosting and flare, making a marginal difference to a careful shooter? Thanks.