A kid asked me this: "I've been shooting with my 6d;70-200;and 580exii. My problem is how do I capture them running,dunking, etc if i can only set my shutter to 1/160 using my flash???!!"
What do I tell him? Pls help, he thinks I am a cool photographer but I really do not know how this works. I would love to help him and learn. THX.
Depending on the distances involved I suggest you suggest to him setting his 580Ex to 'high speed sync' on the back of the speed light. He can then sync at any speed. Then shoot at the widest aperture that will give him his required dof as high speed sync does reduce flash output. Only use the flash to fill.
Or just advise him to crank up the amazing ISO of the 6D and forget flash altogether.