550EX Master Flash off Slave on ?

In reading through the 550 EX manual I recalled that there was a setting to turn off the master flash thereby turning it into just a wireless controller for a remote flash. I have an upcoming event where that would be nice to have this feature so I decided to test it.

Drats! I can't seem to make it work. I have both flashes set to same channel I go through the setting to turn off the master light which starts to blink the little symbol next to the flash head symbol confirming it is set, but the flash still fires? I tried switching flashes and using the other as the master, still same result, both flash (they are two 550ex's by the way). Any ideas what I might be doing wrong?

In the chance it might be a camera issue, I tried both my 1ds MK II and 10D, both same result.

By the way, I do see that it appears as though the intensity is much reduced on the master flash, just not off as the manual states it will be. It does state that it will still send the wireless signal which I thought would be infra-red? Is that not the case?

I searched the forum for master off and didn't see it, sorry if this is repetitive, I typically use my studio flashes not the EX units. I suppose I can get one of the canon ex cables to work with pocket wizzard and trigger them this way. Need to pick that up anyway for when working greater distances etc.

Anyway, a sanity check would be apprecitated on the above EX only configuration.

Thanks!

Jim

I believe that it still flashes, just at an intensity that will not affect the photo. I have not used this, going to experiment with it tonight though.

I tried to use a 580ex and a 550ex as slave and master. They worked great at home but on the job they failed. I tried two different 550's and then gave up and used my always reliable White Lightnings.

The Master will still fire even when the flash for it has been turned off. But the flash you see is not the illumination flash but the command flash used to communicate with the slave flash so you have nothing to worry about.

Exactly right. You beat me to it.
Regards,
Scott

During normal flash operations, there is a pre-flash and then a main flash.

When the master 550EX is set to "no flash" and it still has to send out the command flash, where is the command flash happening?

I assume that the command flash goes, and then the pre-flash on the firing flashes go, and then the main flash on the firing flashes go. So, the command flash must be just a tiny instant after the button push and a tiny instant before the pre-flash.

---Bob Gross---