7D Wireless Flash Trigging - Shutting Off Built In Flash Possible?

So I watched the Canon video on the 7D which states that:

"Built-In Flash fires for frontal lighting or just triggers off-camera flashes"

The video can be found here (under Built-in Wireless E-TTL Flash):

http://www.usa.canon.c​om …tID=329&article​TypeID=125

At 1:16 in the video, it even shows how to set this up in the camera flash settings so that the built-in flash won't fire in the final picture.

No matter how I change the settings around, the built in flash is always firing along with the external flash. I can't get it to turn off.. I just want it to trigger the external speedlights.

I've been through the manual several times and I can't for the life of me find how to disable the built-in flash from firing. Anyone else having this issue?

Is it actually flashing while the shutter is open or are you just seeing the pre-flash communications pulses?

Stephen,

The 7D pulses the built-in flash to communicate with the external flashes before the shutter is opened. It's the so called "pre-flash". That's what you're seeing. The built-in flash is not contributing to the actual exposure if you configure it to only trigger the external flashes.

Ah okay.. that explains it.. thanks.. because I was expecting it to act like my Wireless ST-E2 transmitter and not add any light to the equation. Now I just tested by holding the speedlight right against my body so no light could leak out and yes, you're absolutely right, there is no light from the preflash captured in the photo i took... Thanks for the explanation, I feel much better now.

Hi All, this is weird. I'm having the same issue as Stephen, with the built-in flash firing alongside the slave external flash, despite me setting it that only the external should fire.

And I'm not just seeing the pulse used for communicating with the external flash, the built-in flash indeed did fire, coz I place my hand near the built-in flash and can see my hand lighting up from it in the pic taken.

Is anyone experiencing this?


Patrick

heartpatrick wrote in post #8904038
Hi All, this is weird. I'm having the same issue as Stephen, with the built-in flash firing alongside the slave external flash, despite me setting it that only the external should fire.

And I'm not just seeing the pulse used for communicating with the external flash, the built-in flash indeed did fire, coz I place my hand near the built-in flash and can see my hand lighting up from it in the pic taken.

Is anyone experiencing this?

Patrick

Hey all, right after I posted this note, I went testing it again, and it worked now! the only difference is - i press the 'SET' button when selecting to option to only have the external flash fire, instead of pressing 'DOWN' on the multi-directional controller. I know it shouldn't make any difference, but somehow it worked for me haha. *weird*

Well, even if you set the internal flash not to contribute to the illumination, it still fires when the shutter is open. It has to, in order to be able to sync the slaves to fire at the right moment, when the shutter is open.
But the power is only about 1/512 of full power, and even full power isn't that much for the built in flash.

If you use a 580 EX II as a master, and tell that one not to fire itself, the sync flash is about 1/1024 of full power, but that full power is quite a bit more full than the internal one is capable of.