# How to trip shutters on two cameras at the same time?



## J.R. (Feb 20, 2014)

There was a recent thread on CR where advice was sought as to how to trigger two cameras at the same time. During the course of discussion on the thread, I had asked whether it was possible to sync shutters on two cameras but got no response. 

I am using 600rt x 2 and a ST-E3-RT. 

Canon's official position is that shutter sync cannot be achieved using the 600 rt. does anyone know how to do this? Might come in handy one of these days ...


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## privatebydesign (Feb 20, 2014)

J.R.

I have explored the Canon "Linked Shooting" mode of the RT system, Canon are correct, the shutters fire at slightly different times so if you are using flash it is a non starter. Though as a simple multiple camera firing option it works well.

If you need syncronised shutter release to the exact time a flash will fire, so use one flash setup for two or more cameras, then timing is critical. If you are using the same model of camera I believe a simple spliced in release will work if you are in manual focus, if you are AF nothing will fire them both at exactly the same time. If you use different cameras the only off the shelf product I know will work is the Pocket Wizard MultiMax, this can be used to delay the faster camera to the shutter release of the slower camera, but I am sure there are other products and DIY solutions.


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## Logan (Feb 20, 2014)

this just popped into my head while I was browsing the forum, no idea if it helps you any.

There are those lightning triggers, not sure what they are called but i see ads for them all the time. Any idea how they work? The timing should be pretty precise, a lightning flash is not very long.

Assuming they work like a welding helmet and detect some kind of EM radiation that comes before the light, you could splice one to two cameras, or just use two as long as they arent miles apart, and trigger them with something as simple as a lighter flint or maybe another flash test firing? what do you think of that?


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## Schruminator (Feb 20, 2014)

The lighting triggers are usually a photocell of some sort (think about the light fixture over your garage) hooked up to a microcontroller or something to read the light levels. This controller then is hooked up to a transistor or a relay to trigger the camera. There are circuits you can make without the microcontroller, but it takes a bit more work to be honest.

Regardless, back to the original question: I'm not sure if a cored remote shutter release wired to two cameras will work. If so, splice your wire, hook it up and you're set (MF though, AF will delay things as the camera tries to focus). If that doesn't work, I'd look at using a two pole (or "double throw") relay. Basically it's one relay that has two independent outputs. It should trigger the cameras at the same time while keeping them electrically separate from each other (ie no touching of spliced wires). You'll need something to trigger the relay, but that can be as simple as a 9V battery and your thumb if you don't need super precise timing.

I use 1 double throw relay to control 2 flashes to fire at the same time (and they are muuuch faster than a camera shutter) and it works great. The link below is a picture I took with this set up. 2 flashes almost directly to the right and to the left of the wine glass in a darkened room.

http://www.mschrum.com/2012/10/wine-glass-3.html


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## Maui5150 (Feb 20, 2014)

Pocketwizard Flex TT5s.

Took me a while to nail the set-up but was able to fire a camera in my hand, trigger a remote camera and sync the strobes to have them all go off at the right time


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## J.R. (Feb 22, 2014)

Thanks for the replies ... This confirms what I felt initially that it cannot be done without a specific accessory. 

PW accessories seem to be capable for the job, and I might add a couple of NERO Triggers to the mix but there doesn't seem to be a DIY method.


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## apersson850 (Feb 23, 2014)

If it's OK to have the two linked cameras fire the 600 EX-RT mounted on each camera independently, then that's possible to set up. The flashes will of course fire with a slight time interval between them, but each will sync with its "own" camera.


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