Slave Flash trigger question

I am preparing to buy either the 550ex or the SIGMA EF 500 DG SUPER. (With the possibiliy of getting a 420ex later for more advanced portraiture).

My question is about the slave functions of either of these flashes. If you have only one flash, and it is positioned away from the camera (example: "Classic" portrait setting with flash located at 45 degrees to target and camera directly in front of object), what triggers the slave flash? Is it the camera, IR, cable...?

As mentioned above, I'm looking at either the 550ex or the sigma EF500 DG Super for a start. I understand the Sigma may not co-operate with other flashes (420ex). Would this cause problems when I get multiple flashes? For this reason, should I go with the 550ex and a 420ex later on?

I don't want to go out and spend hundreds of dollars worth of equipment and then realize it won't work for me. As mentioned in a previous post: "I'm no professional, just doing the Family Christmas Cards or portraits of mom, dad, bro, sis... BUT... a casual wedding or Christening could always be a possibility)."

The 550ex will serve as your master trigger if you ever decide to get successive 420ex's added in the future. I probably would not want to put the 550ex on the camera because I don't like using the flash straight-on. If you want to use the 550ex and 420ex off to the sides (or two slave 420ex's), get the ST-E2 transmitter (~$180) and mount it to your camera. The other option is to use the PC sync cord to an off-camera 550ex, which can wirelessly trigger the 420ex. Sorry, I don't know much about the Sigma flash, but I imagine you will need to accomplish the same with just PC sync cords.
Those flashes are triggered by Infrared beams, which work fine indoors but might be more limited outdoors.

I use three 550EX's in a portable lighting set up in wireless ETTL. As long as the red plastic is facing towards the master flash and you stay within the distance Canon specifies you will be fine. Just swivel the flash head so that the red plastic is visible to the master.

First of all, I assume that you are using only the Canon wireless flash system or else Sigma stuff that is compatible.

(One light only)
1. You can put the one flash on the hotshoe, or on the off-camera shoe cable.
2. You can put the master wireless transmitter (e.g. STE2) on the hotshoe and put the main flash wireless slave somewhere else. They communicate by an optical data signal.

(Two or more lights)
1. You can put the wireless master transmitter (e.g. STE2, 550EX, or 580EX) at the hotshoe. Put the wireless slave or slaves elsewhere.

The advantage of the STE2 is that it is very small. The disadvantage is that it is not a flash unit, and it only serves as a master wireless data transmitter to the wireless slaves. Some users prefer to buy a full-blown 550EX or 580EX as the master. It can have its main light enabled for flash, or disabled, and it can still serve the master wireless data function.

---Bob Gross---

Thanks to all of you. As always, we can count on our fellow forumers to share their knowledge and expertise. I will get the 550ex now and use it for 'on-camera' flash and later use it as a flash/transmitter with a 420ex (or another 550ex if some money starts to grow on my trees this spring).

I've actually had a flash positioned on the ground behind a couch (couch between Master flash and slave), red detector or slave was positioned to face the wall (opposite couch).

Slave flash fired every time...Within a studio setting, your wireless setup is pretty open...not true with outdoors since there's less capability to bounce the Master signal.

I sometimes use the Sigma 500 super mounted on camera as master and the 420EX as slave, with the flash ratio 1:4 (that is, the on-camera flash is turned down 2 stops and produces very little light), or turn off master flash function -- so no need for STE2.

Is there a benefit to having multiple 550EX units, instead of a single 550EX and several slave 420EX? The latter is much cheaper.

Also, does anybody know if the sigma 500 non-super can be set up as a slave?

thanks

David

Multiple 550s? they have more output, and they can be used on manual or multi modes as well as auto. The 420EX won't slave if you're using your flash in manual or multi mode.

You learn something new everyday.

I'm wondering the same thing. I just learned how to use my 500 Super as the slave to my 350d's built in flash. It's very cool. Now I'd like to play with multiple flashes... the ST is about $70 cheaper...

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Yes the sigma 500dg super can be a wireless slave to a 550ex, a 580 ex or another 500dg super. Keep in mind canon and sigma use different names for their groups. One is numbered (1,2,3)and the other is Lettered A,B,C)

The 500dg super can also be set up as a digital manual slave ignoring the preflash from your on camera flash. You set the 500dg super as optical slave and select your working apiture and mount it to a light stand of the included foot and you have a 2 flash set up with the purchase of only one off camera flash.

(EDIT) someone pointed out to me that the 500dg super may still fire with the preflash from your on camera flash.

So it looks like 2 off camera flashes will need to be used for multiple source set ups. One master and one slave.