Nice rooster tails!
The 70-200/4LIS with a 1.4xTC becomes a 280/5.6 at the long end (where this pic was taken).
I'm not too impressed by the sharpness of this combo.
Perhaps it was technique as some of the shots of stationary drivers came out incredibly sharp.
I'm sure some had to do with the rather small aperture of 5.6 and the fact that it was moving fast at a good distance.
I wonder what the guy next to me shooting his 5.6 100-400 got.