Help with e-ttl wireless flash system, using a Sigma

Hi,

I own a 350D and a Sigma EF-500 DG super flash.

I've been led to believe that you cannot use the in-built flash in the Canon to act as a master, in order to set off the Sigma as a slave.

Is this true?

If so, is there any way of triggering the Sigma flashgun without buying another flash to use as a master?

Thanks,

Max

The E-TTL pre-flash from the built-in unit will trigger any optical slave prematurely.

If you want to use the built-in as master, you need to hit the FEL button (*) to fire the pre-flash, wait for the slave to recycle, then take the shot.

The Sigma flash will need to be in optical slave mode, and you'll need to set the power manually.

I have a 350D and a Sigma Super as well and Curtis is right, you can trigger it using the internal flash by pressing first the FEL button (*) to disable the preflash and then taking the picture. If you want to minimize the effect of the internal flash what I do is before pressing the * button I point the camera to a white wall from at a 10cm distance, this way the E-TTL system will use the minimum power.

Another way to trigger the Sigma Super is with wireless transmitters from Ebay. There was a review in this forum and I bought them. They work OK without any problems. Here is the link for the transmitters.

Thanks for the help!

Its all working perfectly now, and I'm loving the Sigma, definitely good value for money.

I have been contemplating this but have not had a chance to try this idea out. Would it be possible to cover the built in flash (with hand, sock, whatever) while you press *, so the Sigma does not see the pre-flash, and you would not have to wait for the Sigma to recycle?

rdsmith3 wrote in post #2949369
I have been contemplating this but have not had a chance to try this idea out. Would it be possible to cover the built in flash (with hand, sock, whatever) while you press *, so the Sigma does not see the pre-flash, and you would not have to wait for the Sigma to recycle?

That will work for triggering the slave.

Keep in mind that you will likely also get maximum output from the built-in when you take the shot with this method.

erpetao wrote in post #2945187
Another way to trigger...is with wireless transmitters from Ebay.

The eBay offering states, "Each receiver works with one flash. You can use as many flashes as you wish as long as you have enough receivers." I wonder if one uses the receiver with a 550EX, would it still be possiable to fire a 420EX slave from it (the 550EX)? Or would one really need a receiver for each flash?