Ok, here's the deal. I am almost positive that my 40d is back focusing. I have tried all 3 of my lens, using my tripod, wireless remote trigger and live view for test. I use live view, 10x magnification, focus in live view manually and then half shutter press and the AF moves the focus ever so slighty. I was wondering if someone would mine trying it out for me to make sure it is the camera back focusing and not me. I can put the lens on my D60 and get very sharp images. Thanks for your time.