Neuro:

If I remember correctly, you came to that conclusion a while back.

There was a firmware change on your 1DX that allows you now to AF with a f/8 lens. Is f/8 the limit, or can you go beyond that? Without going beyond the f/8 AF capability, the 2XIII extender can not be used on the 800mm. If the next generation 800mm could get to f/4, then that would be a game changer by allowing the 2X to get even more reach (even at a degraded IQ, some would bit to get the longer reach).

Pat