High Speed Sync 7D 580EX
Yes with an off camera cord, no if using built in wireless.
I wondered why the ball kept getting bigger, then it hit me.
The 7D's pop-up flash is not capable of high speed sync nor is it capable of wirelessly controlling HSS in an off-camera flash. 7D can only do HSS on or off camera via a Speedlite attached directly or indirectly to the hot shoe (which, by the way, must use optical wireless --HSS is not possible via the new radio wireless system on any camera released before 2012).
What you cannot do is remotely change the settings on the 580EX. My 7D and 580EX (first generation) work very well in HSS mode with the Pixel Kings. 2.4Ghz radio not optical also gets me lots of range to work with.
Any of these will work nicely, with the added benefit that you can change all flash settings from the camera (although you might need a 580EX II for that):
Im getting some conflicting info from Multiple sources
can I do HIGH SPEED SYNC using my 7D and a 580ex fllash off camera?
HSS is available for both 'II' & 'non-II' series 4xx and 5xxEx speedlites in most circumstances - including;
Direct, in the cam's hot-shoe
Direct via an OC-E3 or good clone of same
or Via most forms of Canon Wireless - Light/IR version.
However, as others have said, all of the built-in pop-up Canon Wireless Controllers, including the 7D's pop-up Controller, do not offer HSS under any circumstances.
(SCS is not compatible with Canon Wireless - though 3rd party units eg Phottix Odins, facilitate that option too.)
The 'non-II' series units are partially limited in terms of control from an attached cam's flash menu screen. But most functionality can be enabled using their own buttons/controls - and - they make fully functional (& remotely adjustable) Canon Wireless Light/IR type 'slaves'. And that includes HSS, provided an HSS capable 'master' device is controlling the network.
no with the wireless IR system,
I purchased a 600EX RT, and have since returned in favour of my 580ex2, apparently the RT isnt compatible with 7D as yet,
so i stuck with 580ex2 and a pixel king set($140 au) done a model shoot, outside last saturday, using single 580EX2 and 7D, 183 frames,arround corners over 30 metres ,not a single miss flash, 152 keepers out of shoot, many in HSS, and many in ETTL HSS.
very very pleased, now adding a second 580ex2,
note, the yongnue 565 CANNOT do HSS. so for me has to be 580EX2 and a extra reciever from pixel king.