From: "Mark M"

http://www.pbase.com/bret/image/34504445

Why are you shooting at 4f?
Isn't this shot with your 70-200 2.8 L?

1/250 could have been a crispy 1/350 or more at 2.8,
and yes...you'd still have some obvious and nice motion effects...

Can you say "flash sync?"