Multi-flash setup check list

[timmyquest]

I have a 550EX and am thinking about buying at least one (for now) 420EX to work with my 550.

The 550 should take care of firing the 420 correct?

[scottbergerphoto]

Yes. The 550EX works as a Master to the 420EX as slave.
Regards,
Scott

[FrenchAmateur]

Yes, I have both, I confirm.

You can also pilot the 420 Ex (and the 550 EX) with the ST2 transmitter.

[robertwgross]

One trick is that you need to set the (wireless) Master or Slave switches correctly on each flash unit. When used solo and on-camera, they are normally set to Off.

The other trick is that you have to get the 420EX to "see" the IR data signal projected from the 550EX. Either the 420EX has to "look" directly at the 550EX, or else it has to "see" the reflected light from it. But then, that is why the flash unit body will twist around like it can.

---Bob Gross---

[DaveG]

I have a 550EX and am thinking about buying at least one (for now) 420EX to work with my 550.

The 550 should take care of firing the 420 correct?

Yes they will, but after you get the 420 you'll sit with the instruction books (your camera's, the 550's, and the 420's) in your lap and will be very upset when you realize that there's not a WORD in there in how to use the combination of the 550 as Master with the 420 as Slave. All of these instruction books imply is that you'll need either a ST-E2 as a master and then you can use the two flashes, or you'll need a second 420/550 to use with the Master 550 as kind of a dummy.

The oversight is mindless but has a very simple fix. Set the 420 to Group B. The 550 will default to Group A. That's all there is to it, but Canon is too stupid to have instructions that explain it; and if you DON'T do this then wireless TTL is impossible with the two flash setup.

[scottbergerphoto]

I have a 550EX and am thinking about buying at least one (for now) 420EX to work with my 550.

The 550 should take care of firing the 420 correct?

Yes they will, but after you get the 420 you'll sit with the instruction books (your camera's, the 550's, and the 420's) in your lap and will be very upset when you realize that there's not a WORD in there in how to use the combination of the 550 as Master with the 420 as Slave. All of these instruction books imply is that you'll need either a ST-E2 as a master and then you can use the two flashes, or you'll need a second 420/550 to use with the Master 550 as kind of a dummy.

The oversight is mindless but has a very simple fix. Set the 420 to Group B. The 550 will default to Group A. That's all there is to it, but Canon is too stupid to have instructions that explain it; and if you DON'T do this then wireless TTL is impossible with the two flash setup.
Dave,
Your absolutely right. I have gone over the 420EX and 550EX manuals again and again. They both imply that ratios can only be set between slaves, not between that Master and the slaves.
Scott