580 master mode and optical slaves

Perplexed. I'd thought I read everything to know about these flashes and how they interact with other flashes and slave triggers. Found something today that baffled me.

580 master mode and optical slave. I have a 580 in M shooting in a triangle with a 550 in slave and a (Nikon SB or 380ex) completing the triangle.

In 580 master mode the 550 fires no problem. The (Nikon SB or 380ex) doesn't fire. I point the 580 at the floor behind a couch so the (Nikon SB or 380ex) doesn't see it. The (Nikon SB or 380ex) sees only the 550 slave fire and the (Nikon SB or 380ex) fires. Something in the flash from the 580 stops the optical trigger from firing.

The optical trigger is a Sonia unit from eBay. Works like a charm except when the 580 is in master mode and fires right at the slave.

Are you sure the Sonia is not firing at all with the 580 in sight, or is it firing prematurely?

Just not firing. It's the strangest thing.

When the 580 is in master and M mode, the Sonia doesn't fire. Stand in the same spot, same angle, change nothing and only switch off the master mode and it fires properly.

I will do some more testing tonight with my ST-E2, other flashes and see what the hell is going on.

You might have the similar problem I encounter with a Wein Peanut, slaved to a Canon master/slave setup. What happens is that the master 580 in manual mode fires 2 flashes on every shot, a command pulse flash and the actual flash, both in very short duration. The optical slave could be confused by that.

In my situation, I have a master 580 to slave 430, and the Wein slave to tigger a Sunpak 383. All 3 flashes fire in sync as long as the 383 does not see the 580 directly. If the Wein slave is facing the 580 directly, it will trigger the 383 on the 580's command flash, now the 430 sees 2 triggering signals, what I end up with is that the the 430 either not fire at all, or it flashes as the modeling light is turn on.

To solve my problem, I made a little snoot for Wein optical slave, and have to pointed to the 430 in 3 flash setup.

cosworth wrote in post #2834296
Just not firing. It's the strangest thing.

When the 580 is in master and M mode, the Sonia doesn't fire. Stand in the same spot, same angle, change nothing and only switch off the master mode and it fires properly.

I will do some more testing tonight with my ST-E2, other flashes and see what the hell is going on.

I'm wondering if the trigger threshold of the Sonia is set such that the weaker command pulse from the 580 isn't strong enough to fully trigger the sonia but strong enough for it to attempt to try triggering. A good test would be to bring the 580EX closer to the Sonia so that it receives a stronger command pulse and see if that triggers it.