Question for the geniuses on the forum. I have 2 580ex's that I am triggering with the radiopoppers P1, I have a White Lightning Ultra 1200 that I am letting the slave trigger.
My delima is that the White Lightning is triggering but not showing up in the exposure. It seems that the shutter is closed when it fires.
Any ideas??

I have also covered all the infrared areas so as not to trigger it with the preflashes.
I am shooting at 125/spd f8 if any of this helps.

Both flashes need to be in M. If not, you probably have some light leaking out of the master.

Thanks for the tip. I had them in TTL and once I switched to M it worked like a charm. Thanks a ton :-)
I guess I am having end of year brain freezes

The reason it didn't work is because in TTL the 580 EX sends it's info via a flash (right off the 1" by 2.5" white flash). Everyone wrongly assumes that the flash SENDS and RECEIVES of the red part on the flash. It ONLY receives using this.

So in TTL as soon as the 580 sent the first signal flash it tripped the mono and the 580 EX hadn't told the shutter to open yet.

It all happens so fast on the 580 EX that you think it's just one flash burst but in ETTL mode it is really several.

The red lens is the AF assist light. It has no role in wireless control. The wireless sensor, which is only in play when the flash is in SLAVE mode, is the smaller gray window directly below the flash head.

When used normally you should orient the front of the slave toward the flash head of the Master flash, which as crockett mentioned sends the commands via coded pre-flash, then twist the flash head of the slave toward the subject.

I suspect the reason many people have trouble with Canon wireless is that they are clueless and either block the sensor on the slave with a modifier, or don't orient the base of the slave towards the Master's flash head.

In ETTL ratio mode there is actually a burst of 5-6 discrete command and metering pre-flashes. The master first needs to tell the slave what mode to operate in (ETTL or M).

In wireless M mode the Master tells the slave what power level to operate. Then as the shutter opens it sends the command to fire to the slave. So M mode will also pre-flash in master/slave configuration and should trigger the WL prematurely.

In ETTL A:B ratio mode the A and B groups are pre-flashed separately for ratio setting, then once the necessary power computed in the Master it pre-flashes to tell the groups how to set their power as a % of total capacity. Then A&B are pre-flashed together to meter the exposure.

In ETTL A:B C mode after all the above occurs the Master instructs C - via coded pre-flash - to fire a metering pre-flash. Then C is set relative to A:B so it matches. C is intended only as a background light - it shouldn't hit the foreground because it isn't included in the foreground metering.

Great info, Chuck. Of course, Radiopoppers make most of that a non-issue when used in conjunction with strobes. The only thing you still have to avoid is the metering. It's too bad Canon didn't add a simple optical trigger (like the SB-26's) so that people wouldn't have to pony up for individual triggers or default to using ETTL for silly manual control.

A simple optical trigger would be a useless redundancy in the Canon system. Also one of the reasons I switched from Vivitars to the 580ex was because I was using simple optical triggers and other flashes would trigger my slave. Simple optical triggers are simply no longer a viable option for a flash system designed to be use on location.

The old EZ system had the option for using wires to connect the flashes and Canon still sells some of those obsolete parts on its on-line store site. But when it designed the EX system it decided to cut all the wires. The OC-E2, the only wire in the system is only 2ft long to move a Master flash on a bracket or hold it overhead.

The radio poppers are a neat idea, but spending $500 to control $800 worth of flashes the 5% of the time the built-in system doesn't work just doesn't pass my common-sense test

There are a lot of things I wish Canon had done differently and hope they will do in my lifetime. I posted my wish list a few weeks ago: http://www.fredmiranda.com/forum/topic/719853

Chuck

Yup, saw that. But I disagree about it being useless. There have been numerous times when my PWs or Skyports decided to not work and it'd be relieving if I knew that I could at least fall back on the opticals. Newbies would also be able to start off with that and eventually move up. The optical triggers on ABs are reliable enough IMO to rely on fully when indoors, and that's really all I'd want from a sensor on a speedlite. The SB-800 also has a sensor, and the 580II has fewer features and yet still costs more.

Great info guys thanks for the in depth responses.
I do like Canons optical system most of the time but I went with the radio poppers because I was getting really (I mean really) bad results outdoors with the Canon system. Since outdoors is more like 50-75% of my shooting it passed my common sense test to go with poppers

If they could have an optical backup that you could turn on or off that would be sweet too.