Nope, the picture was not photoshopped, and the lens is not hanging from strings, nor is there a hidden tripod. I know, because I shot it.
I am the editor at akam.no, and you can see the original shot and more here
. The guy in the picture is our freelancer Paal, and he really WAS holding the lens like that. Only for a few seconds, but long enough for me to get the shot.
By the way, there was no battery in this particular camera, so we didn't get to try the focusing speed with the 800 mm. We did with other lenses though (40 2.8 STM, tamron 24-70 2.8 VC), and it seemed more or less like the 650D in LiveView. Not fast, but not too bad either.
(CanonRumors is using the picture by our permission)