triggering 600ex with another ST-E3 with a ST-E3

[scottgoh]

Hi,

i am two 600ex-rt and two st-e3.

with 2 st-e3, I know I can trigger the 5D3 to take photo wirelessly using a st-e3 on the 5D3 and hand holding the other st-e3. with this setup in mind, can i also trigger a 600ex-rt to fire off too along with the click of the shutter on the 5D3?

thank you

Scott

[Skirball]

You need one of the ST-E3 on the hotshoe to trigger the flashes, I doubt you can do this and use it to trigger the shutter at the same time.  That said, using two ST-E3 to trigger a shutter is the epitome of overkill, but I guess that’s par for course around here.

Either buy a cheap generic shutter remote (which will be optical – line of sight), or get a set of Yongnuo RF-602.  They’re only like $25 (but for a 5d3 you’ll also have to get a converter to go from phono to Canon's three prong plug), unless you’re already using one with the ST-E3.  The RF-602s work great and you don’t need line of sight since its RF. 

[TCampbell]

I think you should be able to do this but haven't tried it.  You can only have one commander and everything else has to be a remote and they all have to be in radio mode.  

To make this work, the ST-E3-RT mounted in the camera's hot-shoe needs to be the commander/master. 

The off camera flashes as well as the hand-held ST-E3-RT need to all be remotes (aka "slave" mode.)  

You can also use one of the remote 600EX-RTs to trigger the shot.  Page 68 of the Speedlite 600EX-RT manual shows how to do this.  

[Skirball]

But in that mode the ST-E3 in the hot shoe needs to function as both a slave (shutter) and a master (flash).  Can it do that?

If you don’t need both of your flashes off-camera then I believe you can just put one of the 600s on the hot-shoe and use it for lighting and triggering the other flash.  Then I think you can just use one ST-E3 to trip the shutter.

[TCampbell · Accepted solution]

I just did a quick test... I don't have an ST-E3-RT so I had to make due with a couple of 600EX-RTs.

BUT... I used one of the 600EX-RT's on-camera as the master.  I then used a 2nd 600EX-RT as a slave, and used the shutter release button on the slave.  

The slave tells the master to fire, the master then tells the camera to take the shot and the whole thing plays out just as if I had used the on-camera shutter in that the camera does all the E-TTL II stuff (metering & pre-flash metering, set's power levels on the strobes, and then takes the shot.)  Both flashes fire.

So its looks to me that the remote light can do the same thing as pressing the shutter button on the camera.

Usually the camera is going to need to be pre-focused in this situations, so I pre-focused the 5D III and then put the lens into manual focus mode so that focus wouldn't be an issue.

BTW, in case anyone who does _not_ own a 5D III (or a camera made in or after 2012) reads this... this wont work with just any Canon camera.  The newer camers has the ability to communicate with these new radio-triggered speedlights through the hot-shote.  I have a 5D II, for example, and this will _not_ work through the hot-shoe on a 5D II, but Canon does make an accessory cable.  The 600EX-RT speedlights actually have a plug on them that connects to the wired remote shutter release port on the camera body of older cameras.  I have tested the remote shooting capability with my 5D II  (using the cable) and it does work.

[Skirball]

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@TCampbell wrote:

The slave tells the master to fire, the master then tells the camera to take the shot and the whole thing plays out just as if I had used the on-camera shutter in that the camera does all the E-TTL II stuff (metering & pre-flash metering, set's power levels on the strobes, and then takes the shot.)  Both flashes fire.

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That's pretty handy.  I'd prefer a dedicate shutter remote so I can keep my flashes off-camera, but in a pinch it's nice to have that flexibility.