Originally Posted by candyflip

Plenty, because the entire frame stays in focus. You'll likely still be a bit shaky without some sort of rig, but everything should remain in focus when doing what he's saying here. You're obviously losing any DoF, but that's the point

Unless you're on sticks with preplanned shots, this is the best method for getting clear shots with a DSLR and not needing to constantly worry about pulling focus.