master/slave Flash IR info

[Erik_L]

the ST-E2 and 580 EXII can be used to control multiple slave flashes via IR, correct?

Has anyone ever tried to "learn" this IR pattern on a universal remote control? would it be possible?

discuss.

[apersson850]

The 580 EX II emits visible light, but apart from that, you're right.
The flickering may not at all be in the same style as remote controls use, but I'm just guessing. I don't know.

[Erik_L]

I would love to find out. It would be so cool to have "remote" flashes that work with my Harmony!

[apersson850]

When using E-TTL, Canon's wireless flash controllers send a two byte code for each pre-flash, then a five byte code prior to actually taking the picture, then a trig flash when the shutter is open.

In manual mode it's just the five byte code, then the trigger flash. How much data does a TV remote send?

[Erik_L]

I don't know. probably less than that. is it the flash itself that causes the trigger?

IR used to send "config" data to the slaves, then actual flash triggers the other flashes... is that correct?

[apersson850]

No.

Whether it's IR or visible light depends entirely on the transmitter.
They are all flash units, but the ST-E2 has a filter in front of the flash tube/reflector, converting it to IR, or at least near-IR.
So either you have an IR device (ST-E2), and then it's all IR, or you do not, which implies you use a 580 EX II or the internal flash of the 7D, and then it's all visible light.

There are some older models too, that work as masters.

[PacAce]

Originally Posted by Erik_L

the ST-E2 and 580 EXII can be used to control multiple slave flashes via IR, correct?

Has anyone ever tried to "learn" this IR pattern on a universal remote control? would it be possible?

discuss.

Yes, I've actually "learned" a remote to trigger my slave flashes. The only issue is that what the remote learned is a particular command pattern that's only good for a particular lighting situation. It's good for that particular shot but not for any other shot if the conditions change. In other words, trying to program a remote to trigger slave flashes will be an exercise in futility unless the lighting conditions are held constant every time the remotes are used to trigger the slaves. And, on top of that, why would you want to trigger the slaves with a remote other than to try it just to see if it works.

[Erik_L]

Originally Posted by PacAce

other than to try it just to see if it works.

you nailed it.