Canon 70D remote flash trigger

[tamernagy]

Which Canon speed light will work off camera and be triggered by the in camera remote flash trigger feature ??

[Digimik]

Ha! Yeah...funny story in how the point-n-shoots triggered your camera. I just got the RF-603C. And I'm sure all will be well now that I understand how all this flash stuff works...or rather...is triggered.

[diverhank]

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@Digimik wrote:

 I don't understand what the point of an external flash being fired by the camera's builtin flash because for me, the whole point of an external flash is so the builtin flash DOES NOT fire as that sort of lighting doesn't look good.

In trying to make the the external flash fire remotely without the internal flash being fired is an assumption on my part that since the 70D is sending wifi data (if enabled) and also IR signal, it would fire the Speedlite. But apparently, it seems I STILL need some sort of trigger to be placed on the shoe or at least, a cable?? 

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Digimik, I'm pretty sure that the built-in flash output when used as a trigger is not used in the exposure - the camera shutter opens after the initial burst.  I read that somewhere but don't remember to reference it here.

If you dislike the built-in flash, you can buy a Canon ST-E2 controller which is mounted on the camera flash shoe.  I use one because my 5DMkiii doesn't have the flash trigger :), well it doesn't even have a built-in flash :).

[TCampbell]

Correct, you can disable the use of the on-board flash for purposes of "exposure".  

You WILL STILL NOTICE that the flash fires.  But keep in mind how E-TTL works.... the flash actually does a lot of pulsing in a very brief moment in time such that it "seems" like it just flashed once, but in reality it flashed several times.

The E-TTL system does some pre-flashing to test flash power for the exposure and also an onboard flash used as a commander will flash signals to remote flashes in order to tell them when to fire and how much power to use.  

A fraction of a second later, when the camera shutter opens, only the remote flashes will fire and the onboard flash will remain off.  

To a human observer, it will seem as though all flashes fired pretty much at the same time.  But when you check the image captured by the camera, you'll see that only the remote flashes fired when the shutter was open.

I hope this clears up the confusion about seeing the on-board flash.

Keep in mind that this is an "optical" system, requires line of sight, and that the remote flashes all tend to have their receiving unit in the lower half of the flash body (not up in the head.)  That means if you are outside using flash during daytime, you may need to turn the lower body to face your 70D (and since the flash head can tilt and swivel, just point the head in the direction where you need it.)

As Diverhawk points out, the ST-E2 uses a red emitter to do the optical communication and not the white-light flash.  

The ST-E3-RT commander uses radio, but requires a radio capable flash (currently only the 600EX-RT has radio capability... btw, the 600EX-RT also has optical capability as well... so it covers both the optical and radio world (but can only operate in one mode at a time.)

[MikeSowsun]

When using the 70D's built-in flash to trigger a Slave Flash, part of the "Command" flash WILL be visible when the shutter is open. This happens even if you disable the flash from firing in the Wireless menu. Normally you won't see it but it can be a problem in certain circumstances.

I first noticed this when using my 7D for Macro photography. I could see some flash highlights from the built-in flash even with it set to disable.  This is easily confirmed by taking a photo in a mirror. 

The easy fix for this is to use some kind of a diffuser or bounce card to direct the flash away from your subject and towards the Slave flash. 

I found I could just hold my hand up in front of the pop-up flash to block the light, and it would still trigger the Slave flash. 

Canon 70D manual

[StephenM]

My sincere THANK YOU to all who contributed to this thread. This one thread answered questions that I could not find anywhere else. I can now proceed with getting a flash unit and not feel like I'm going in completely ignorant. You folks are GREAT!

[Rockwell18]

Hello folks, I just found this forum and find it pretty interesting.

I do have another question reguarding the 70D and flash (go figure), anyway, with the purchase of this new camera, I received a pamphlet called Canon Flash Classroom and in there (pg 😎 it talks about using a flash to remotely trigger the camera. They specifically show the Speedlite 270EX II firing the camera, diagram and everything.

Anyone know about this or has ever done it? Can other Speedlites do this?

Thanks,

Rockwell18

[Skirball]

It makes sense that it's possible, and it's always nice to have options for when you're in a pinch.  But that said, I've never tried it, there are too many other options these days with WiFi control from your phone/tablet, IR blasters from your phone, RF triggers, and good old IR remotes.

I'm assuming that it just looks for the first pulse of a flash, no complicated patterns or anythign.  So any flash should work if you just push the "test" button.

[Phoposterous]

Strangely, the 280exII does have a remote trigger built in.

As far as I know, none of the other Canon flash units have this feature. It is located approximately where the rotate-release button is located on the 400-500-600 series flashes, which can be confusing at first.

It only works in delay drive mode - probably only in two second delay drive mode, but it might vary on different models.

This is the weird thing - you have to point it at the camera was you would the RC6 remote, THEN point it back at the subject to use as a flash two seconds later.

Who dreamed that up? A flash unit you can take off the camera and use as a remote.

Operationally, it makes sense. It's a line-of-sight remote. But from a user perspective, how often do you need a hand-held flash while you are working from the front of the camera, and then only need a remote trigger that fires the camera two seconds later?

[Skirball]

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@Phoposterous wrote:

Operationally, it makes sense. It's a line-of-sight remote. But from a user perspective, how often do you need a hand-held flash while you are working from the front of the camera, and then only need a remote trigger that fires the camera two seconds later?

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No idea.  I do frequently walk around holding a flash and shooting remotely (light painting), but I don't maintain line of sight.  Nor do I want to deal with flashing the camera then the scene.  I use a RF trigger in one hand, and hold my flash (built in RF receiver on separate channel) in another.

[uekral]

Very helpful.  Thank you.