580exII question

[trueblue123]

I have on 580 exII and I also have a quataray 900wa. I just ordered another 580 exII today. The quataray has a built in slave unit that will allow me to use it off camera, which is what I want to do. But does the 580exII work on the same principle? Meaning it wants to see another flash. If so why wouldnt I just stick to the quataray. Or does it search out a signal from the the Master 580?

[PacAce]

No, the 580EX II off camera cannot be triggered by just any flash going off. It will be looking for "intelligent" commands from a master that's on the same channel as it is.

[trueblue123]

thanks, now the other thing is line of site. Do I have to have it in a straight position to recieve the command?

[PacAce]

thanks, now the other thing is line of site. Do I have to have it in a straight position to recieve the command?

Line of sight is best but it's not absolutely necessary to have LoS as long as the slave can "see" the command signal from the master such as from reflections off walls and ceilings. Outdoors, where there usually is nothing for the signals to bounce off of, LoS would be essential.

[trueblue123]

Thanks you very much!!

[Curtis N]

You need one of these to use the 580EX II as an optical slave:
http://flashzebra.com/opticalslaves/0100.shtml

It's too bad Canon didn't design the 580EX II with built-in optical slave capability, but the Flashzebra attachment is a pretty cheap and compact accessory.

[trueblue123]

whoa, what are you saying, I thought you could use the other 580 to trigger the slave unit.

[Curtis N]

If you want to use Canon wireless flash, then you put one 580EX II in master mode and the other in slave mode. But if you do this, the Quantaray may be triggered prematurely by the command flash.

If you use the optical slave unit I linked to, then all three units can be used together. One 580EX II in manual mode connected to the camera, one 580EX II in manual mode with the slave unit, and the Quantaray in optical slave mode.

[trueblue123]

oh ok thanks!