600ex and 5D Classic

[Peter]

Canon tells me that 5D and 600ex won´t work in radio mode if I don´t use 1/100 sec or longer.

The 7D shouldn´t  work either, but does work with High speed sync. My question is if 5D works with High speed sync in real life.

http://www.p4pictures.com/2012/07/using-the-speedlite-600ex-rt-with-pre-2012-eos-cameras/

[iND]

BE ADVISED:

The full use of radio mode (groups) can only be taken advantage of with the newest canon models 5 D III and 1 Dx

NEW – GROUP mode – "Gr" appears as flash mode on Master Unit
This is one of the premier feautres of the Canon radio-based Wireless E-TTL system.

It requires an EOS 5D Mark III or EOS-1D X (as of March 2012) camera body to perform;

for technical reasons, it's unfortunately not possible with previous EOS SLRs.

[Peter]

http://photography-on-the.net/forum/showpost.php?p=15248882&postcount=17

Seems like it works anyway.