Paul C. Buff, Inc. Technical Forum

Hi guys,
recently I decided to start a life as a strobist after many years of continuous lighting.
I have a 20D, 580EX, 420EX, a CST and a CSRB. I don't own a second receiver now
but I thought I can use one wireless set in a master/slave combination. That didn't work!
When I have my 580 wireless as a master and the 420 as slave the slave fires 1/2 second
later. Master/slave alone works. I can also use both flashs alone wirelessly.
Can somebody explain that to me?
Sure, on the long run, I will get another receiver for my second flash and even replace my 420 with another 580 for several reasons.

THANKS for the help!

Not being intimately familiar with that specific combo, i can give you a possible reason, based on how these work in general. The master/slave runs off a TTL based system. Since the "master" is not getting TTL information from the camera, it does not know what to tell the "slave". In fact i am surprised the second flash fires at all in that configuration. The least expensive solution would be to use a basic optical sensor attached to the hotshoe. However, this does suffer from the same limitations radio remotes are made to correct (line of sight, high ambient light, other photographers)

TS

I do not believe you can (easily,at least) mix radio (CST/CSRB) wireless and visible/near-IR (CanonETTL) wireless.

Good explanation of Canon Wireless at:

http://super.nova.org/DPR/#Canon

Specifically:

http://super.nova.org/DPR/Canon/MultiCanon/

John

My 35mm gear is all Canon, and I have been using multiple 580EX, 580EXII strobes either alone, or in combination with studio lighting since the 20D hit the market. ETTL and ETTLII are nice features, but can be picky about needing good line of sight, or reflective surroundings. Also, the communication chatter between the master and slave units before and during the shot makes the system unsuitable for a mixed (manual/auto) lighting environment.

In your case, being forced to use your most powerful strobe as a camera mounted master controlling your weaker off camera "slave only" strobe limits what you can do with your setup even more. The best solution is to use your Canon strobes in manual mode, and pop them via radio control. You can even mix the CyberSync system with non PCB radio units like the PW, and that works very well in practice. The cheaper solution is to direct wire your Canon strobes to the PC connector on the camera body with hotshoe adapters and a splitter, or use cheap flash sensing hotshoe slave adapters on your Canon strobes until you have the budget for more radio receivers.

In any event, learning to use your Canon strobes in manual mode is a breeze, and will lead to repeatable results. Get comfortable with it quickly. Just make sure that you set the custom function for auto sleep mode in your strobes to "off", or just when you get your setup right, your strobe will fall asleep, and you miss the shot... :).

Voyager