600EX-RT Speedlite & ST-E3-RT Speedlite Transmitter
The same, but different - optical and wireless capability and an extended zoom range. Nikon CLS watch out!
The future for Canon off camera flash users is about to change. Canon have introduced the 600EX-RT Speedlite and ST-E3-RT Speedlite Transmitter, a true wireless system which relies on radio signals in the 2.4 Ghz band (like WiFi) networks. So no more line of sight, no more being overpowered by the ambient light, nothing but true wireless freedom.
Top view of the ST-E3-RT, identical to the 600EX-RT Speedlite!
I managed to get a look at the units at Focus on Imaging and first impressions are favorable. The UI (User Interface) has been totally redesigned and is mirrored on both the 600EX-RT Speedlite and ST-E3-RT Speedlite Transmitter, so change one, the other updates automatically.
Until I can get my hands on them to play with, it's well worth visiting Sly Arena's blog for a full rundown: http://pixsylated.com/blog/video-canon-600ex-rt-speedlite-st-e3-transmitter/http://pixsylated.com/blog/video-canon-600ex-rt-speedlite-st-e3-transmitter/