I have the Yongnuo RF-603 / C3 - bought Set Radio Trigger and flash trigger for my Canon EOS 20D! everything works great, the things do what they should, the processing is also very good! as Funkauslöser or simultaneously trigger multiple cameras used. Here are small tips: The flash shoe of RF-603 / C3 have neither a lock nor a thread for a tripod. My workaround: Connect ETLII cable with threads on lightning, the other end of the cable to the RF-603 / C3. Now the flash can be fixed to a tripod and remote trigger works by cable. A RF-603 / C3 connected to the 2.5mm jack plugs with the Canon EOS. The other taken in hand. Everything turned on - Focusing works (button pressed halfway) / remote tripping functions (button pressed all the way) Camera Remote control with flash on camera Speedlite directly to camera, RF-603 / C3 via cable to the camera, the second RF-603 / C3 in the hand. Everything turned on - Focusing works / remote tripping works / Lightning incl ETLII work (as expected)..
Video Tips: in German 100m Lightning and Radio Remote Trigger Yongnuo RF-603 - by www.enjoyyourcamera.com - YouTube Associated Item: http://www.youtube.com/watch?v=WEuawoTMR5c