Upload & Sell: On
Fred Miranda wrote:
I have heard that the 800L does not have the best AF response; therefore the results could be very close with the 400 II + 2x III coming at last.
Fred, 800L has a pretty good AF response on the upper focusing distance limit setting which is 20m (60 ft) to infinity. That is fairly long, and it obviously works best on bigger targets.
However, if your target crosses into the 20m zone, or if it emerges unexpectedly within it, you are snookered.
If you set the lens to the full limit switch setting, i.e., 6m (20 ft) to infinity, then you are confronted with a major defocus problem unless the lens happens to be prefocused to your target.
It is also worthy of note that 1DX seems to handle the extreme lens defocus better than anything else I've had before, and it does drive 800 L faster to focus.
For the above reasons as well as the 800L weight/size, I have dedicated that lens to stationary/slow target duty.
However, Tim Kuhn and another guy on the N&W forum keep doing BIF shots with 800L much more than I ever have, and they are getting very good quality keepers.