IMO, Canon really dropped the ball when they disallowed autofocus at f/8 on the Canon 7D. I know that hemongous ISO capability and video is what sells cameras these days, however the addition of the f/8 autofocus capability would allow photographers shooting the 400mm f/5.6L lens to retain A/F using a 1.4x TC. Additionally, it would allow photographers ahooting with the 70-200mm f/4L IS lens to use a 2x TC if they desire. I would not desire this but would love the ability to convert my 400mm f/5.6 lens to a 560mm f/8 and still retain (even if rather slow and with center point focus only) A/F.
Is there any type of aftermarket fix which would allow me to retain A/F with the 400mm f/5.6L lens + 1.4x TC. I don't wish to tape off the contact points. However, since people have successfully done that (even with slow focus results); it seems to me that this might be possible!