# Speedlite transmitters ST-E3-RT and ST-E2 at the same time?



## stonerobertc (Mar 11, 2014)

Does anyone know if it is possible to use both the Speedlite radio transmitter and the Speedlite optical transmitter at the same time with one camera by using a PC terminal and an extra shoe or something like that? I have a 5DMkIII and an optical transmitter with several flashes. Considering purchasing the new radio Speedlites. Any idea if both transmitters could somehow be connected to a camera at the same time and if they would work together so that you could mix radio and optical slave flashes without having to use the 600EX-RT as optical?


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## neuroanatomist (Mar 11, 2014)

I doubt it. The PC terminal is "dumb", it only carries the signal to fire. I'm pretty sure the Canon transmitters expect more communication from the camera than that. Even if it worked, you would not have any of the control capabilities get with a Canon transmitter mounted in the hotshoe. 

Instead, if you want a blended system like that, you have a couple of options. You could use the RT set up in the hot shoe, and connect a dumb wireless trigger system (Cactus, etc.) to the PC terminal, with wireless receivers for the non-RT flashes. Alternatively, you could get Sonia (green) optical slave triggers for the non-RT flashes. Either way, you would need to set the power on the non-RT flashes manually, the difference would be optical versus dumb radio triggering.

If you can afford it, go all in for the RT system, it's truly excellent.


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## stonerobertc (Mar 11, 2014)

Maybe a non-Canon off camera cord that has a hotshoe on the camera end of the cord and a second hotshoe on the other end of the cord. That way, both transmitters could be in a hotshoe?? I see a lot of potential for conflicting signals to the camera, but you never know until you ask (or try it)? I thought maybe someone had tried it.


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## neuroanatomist (Mar 11, 2014)

stonerobertc said:


> Maybe a non-Canon off camera cord that has a hotshoe on the camera end of the cord and a second hotshoe on the other end of the cord.



If you carefully read the descriptions of those dual-hotshoe cords (at least, all of them that I've seen), they state that the E-TTL signal is passed to only one of the two hotshoes, and the other is manual (i.e. just a fire signal like conneting something to the PC terminal).


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