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600EX RT dual masters?


I was using 4 600EXs last night for the first time. My normal setup is two camera each with a speedlight set as master and two slave flashes on stands. In the past I've used Radiopoppers and have had no problem with each camera's flash being a master. I immediately notieced with the 600EX though that which ever one was turned on first as master it gets the green link light and the second one gets the yellow problem link light. 


Does anyone know if there can only ever be one master with the 600EX?


I'm using 5Dmk2's and not mk3's. I know the group function might be different but that doesn't work on the mk2. So I'm using the standard ol' master/slave functionality. Would you be able to set up dual masters in the group function using a mk3?


Any help apprciated. This is a deal breaker for me. I run it this way so I can one long camera one wide and with both masters set the same can get nearly any shot at any moment in the room. Will be difficult/impossible to change my working style because of this. Too bad too because I really like the light/power or the 600EX. 


Rising Star

Check out the "Linked Shooting" part out in the manual. I won't be using it so I never read it. Not sure if it requires 5D3 to work though. Good luck.   


Yes indeed you can use multiple masters with the radio flash system, regardless of which generation of camera you use.


The key limit is 16 devices in a single system, so 10 masters and 6 slaves or 2 masters and 14 slaves.


Also the manual (page 60 in mine) indicates that when multiple masters are used the link light is only lit in green for the first master switched on, the other masters are in orange.


I have just tried it out with my 5D3 and 7D using an ST-E3 on the 5D3 and a 600EX-RT on the EOS 7D, both cameras are firing a pair of 600EX-RT flashes set as slaves. Of course the EOS 7d doesn't support the group mode like the EOS 5D Mark III does (amongst other things).



Brian - Canon specialist trainer, author and photographer

Thanks for the reply. I had read that the yellow light means not connected. Of course I didn't read the manual to verify this so you got me there. Thanks for pointing that out. I will try and do a controlled test.


So having a group capable camera and also one too old to take advantage of the group feature, what's your opinion? I've heard it's the best feature of the flash. Is it so good that it's worth upgrading to the MKiii? Also, is the MKiii that much better than the MKii that it's worth the upgrade? Basically with the difference in quality between the MKii and the MKiii plus the bonus of being able to use the group feature of the 600EX, do you think I should just swap my MKiis out for MKiii? It sounds like I'm already selling myself on this but I would love the opiinon from someone who's used all of these things together. I shoot mostly weddings.




Group mode is so fun to use, it's become my default solution. I did a shoot at the weekend, and used a pair of 600EX-RTs in the background of the picture aimed at the camera, with a main light in E-TTL up front in a softbox. I can increase or raise the power of the back lights or switch them on/off all from the ST-E3. While you can do the manual and E-TTL trick with the old pulsed light system, you need to set manual and power level on each manual flash, this means more walking round making changes and less flow in the shoot.

I find that manual is the way to go when aiming flashes back at the camera.


I've used a 5d2, but never been a fan of the 5d1/5d2. I tended to use 7d/1d cameras instead, but when 5d3 came out I bought one of the first I could get. To me it's a way better all-round capable camera than the old 5d2. Image quality is a little better but the AF is way better. I have shot kickboxing from the ringside with a 50mm f/1.2L and no flash at ISO 6400 and it works great. I've also shot world rally cars in the dust of Finland in the summer, no problems.


So if you're close to thinking the 5D3 is for you then group mode is a real nice feature to get (also works on EOS 650D/T4i, 1D X and EOS M) and the rest of the camera performance, AF, drive speed, sealing is a step forward too. I've found that with the 5d3 I do less focus and recompose and instead use the rear joystick to move AF points around the frame and shoot that way - the AF is so much more capable. Just set it to only allow you to use the cross-type points.



Brian - Canon specialist trainer, author and photographer