As a final check before going for it. I am Interested in any owner's experience shooting freehand in a studio.
I am assuming, that I won't have any camera shake problems using this freehand with a 70-200 F2.8L IS USM II in the following studio scenario.
[e.g. 5x Bowens GM500 Pro's, these 500 watt units have a flash duration of 1/2,900 sec; shooting ISO 160, s/s 1/160 F11 to F2.8 - mainly @ F8, with I.S. On - normally set between 70mm and 100mm, but occaisionally at 200mm for a head shot].
My logic is:- the effective ss is therefore 1/2,900 sec. So with IS on, there should be no hand shake blur.
But having read a few posts about how fussy the huge detail can be and the length Canon went to avoid the issue e.g. Reinforced baseplate, dampened mirror mechanism etc. - I just want to double check my logic is totally right, as using a tripod is out of the question!
I am fully expecting, when using this for outside Portraits, without main flash, and maybe even with minimal back-fill flash, that I will have to take care, and maybe even use a tripod for the best natural light images,when exposing for the background, where the fill flash wont reach e.g a Portrait with say a Landscape Background.
Any views welcomed - as I can't afford to keep the 5D3 as well. And its got to work as effectively as my 5D3 can in the studio.

I see on Canon Price Watch, the 5DSr has come down to $3249 street price...the current UK retail price is $4855 US dollars! That article I linked on Panamoz does seem like the *infamous* NYC camera shops. They do get a majority of positive reviews on E-bay since they are quite a bit cheaper then authorized re-sellers. They just have a small office space from which to market and sell electronics items that are sitting in different warehouses. There may be a delay, and you're not getting a Canon warranty. But it certainly is cheaper and you may not have any problems with the transaction: that's always the luck of the draw since these shops don't have customer service. It's also not as bad as some of the worst bait and switch shop horror stories I've read: the worst one is probably the seller refusing to send the camera until you buy an expensive battery and/or memory card.
