7D2 & 600mm f4 ii for BIF?

[neuroanatomist]

But when birds are moving fast it lets me down. Works great for hockey, great for more or less stationary birds, great for the fire department helicopter fly by, birds in flight against a noisy background w/ the 600mm? Not so much.

Focus is the issue for me and BIF.

Interesting. I've not had any significant issues with my 1D X and 600 II (without or with a MkIII TC). Perhaps the iTR feature (the main difference between the 1D X and 5DIII AF) makes more of a difference for BIF than I thought.

Below are a few examples (not generally what I consider good shots, but they do show BIF tracking against a complex background):

 

[rpt]

Sometimes 960mm FOV is not enough

Here's a BIF at 1920mm - 7D2, 600mm f4 + 2X tele, f8, iso 640, 1/3200, tripod

Rising to the Perch by seattlebirdman, on Flickr

WOW! Beautiful capture. 8)

WOW!