I don't think I'd try the Kenko Pro on the AF 70-210 lens. The rear element extends well past the mount and is dangerously close to touching the front element of the TC. The closest I can measure is it's within 1/64" of touching. I won't even try it on my lens. Also while the lens gives fairly good performance on it's own I doubt it would be very good with the TC. The AFS 70-200mm with or without a TC will give superior results.