can I do this with canon's ettl system?

[doubledragon]

I'm wondering if this lighting setup would work with canon's infrared-based ETTL flash system...

Outdoor location, ambient light in background. (sunset, landscape, etc.)
camera + 24' ettl cord attached to 580ex (softened with shoot through umbrella) + a slaved 430ex 12 feet behind the model (snooted) to provide a rim / hair light.

Will canon's infrared-based Ettl flash system fail in this situation? will the umbrella and/or model block the slaved flash too much?

http://farm3.static.flickr.com/2522/4158641676_3744ef4851_o.jpg

[ericski]

I'm not sure but that seems like it is pushing the limits of the system. Especially outdoors. Inside you can usually bounce the IR signals but outside, not so much. I think the model is going to be the biggest signal blocker. I haven't really had my shoot through umbrellas block signals much.

[GerBee]

No, probably not, it might work but that'll depend on your location and the bounce effect of the IR signal. However, if you used a reflector umbrella you could mount the flash gun backward so each could see the IR signal.

[nyktrade]

I think you are probably going to need to use Pocket Wizards miniTT1 and flexTT5 to ensure the signal stability.

[dmward]

If you are using the 580EX as a master, the ETTL signaling is accomplished by pre-flash.
It might work, providing the 430EX receiver window (the small dark area above the focus assist red cover) is positioned to look directly at the 580EX. While the shoot through is defusing the 580's light it will transmit the pre-flash so how knows.

[PacAce]

For sunsets, it'll work. However, if done during the day, it'll depend on where the sun is and, the time of day and how brightly the sun is shining on the shoot-through umbrella or the slave flash IR sensor panel.

[bobbyz]

Why not get a simple long sync cord and run it to the 430ex. You don't need to use it as eTTL slave for hair light. You already running one wire, what is one more. And sync cord is cheaper than eTTL cord.

BTW - If you doing this outside with sun, why not use sun as rim/hair light?

[Peacefield]

No, it will not work.

From a daylight perspective, it depends on how bright the environment still is, but generally, daylight does not permit use of infared.

More importantly, the signal will not pass through your subject (not sure about the umbrella, but I suspect not through that, either).

I do weddings and always try to get a few shots that are backlit. One day, my triggers were giving me trouble so I tried it with a pair of 580's; one on camera, the other held by my assistant opposite the couple from me. The flash never fired; he had to come out a bit from behind the couple for them to communicate.

The simplest, cheapest way to go is get an optical trigger for the second flash. They're about $10 just about anywhere and it will cause your second flash to fire when it sees the first go off. You won't have ETTL so you'll need to work the second flash in manual. But given that it's just a rim/hair light, exposure is a little less critical.

[c2thew]

"The simplest, cheapest way to go is get an optical trigger for the second flash. They're about $10 just about anywhere and it will cause your second flash to fire when it sees the first go off. You won't have ETTL so you'll need to work the second flash in manual. But given that it's just a rim/hair light, exposure is a little less critical."

just don't be angry when other people trip your flash with their cameras.

[Peacefield]

[quote=c2thew;9138122just don't be angry when other people trip your flash with their cameras.[/quote]

Absolutely; these are completely unsuitable for a family event or wedding. From what you're describing, I'm assuming you're the only one with a camera and a flash.