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Optical Slave Trigger for Canon EX Flash?

Pierre Bellavance , Mar 08, 2005; 09:40 p.m.

I'd sometimes like to use my 580EX and/or 420EX flash with my strobe lighting system as an additional light.

Is there an optical flash slave trigger available that would trigger a Canon EX flash?




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Mark Cohran , Mar 08, 2005; 10:26 p.m.

Sure! Any shoe mounted optical trigger will work. Wein makes one, as do several other manufacturers. You local camera shop should have one for under $20 USD.

Bill Goldman , Mar 08, 2005; 10:39 p.m.

The 580EX in manual mode allows you to adjust the proportional output and should work fine with most any hot shoe type optical slave trigger, such as the one from Wein, unless the polarity is reversed. The 420EX has no manual mode and will probably fire at full power with an optical slave trigger.

The only possible problem is that these devices have a metal hot shoe which will short out the additional contacts on the 580EX or 420EX foot. I don't know what effect this will have on the Speedlite.

Assuming your studio strobes are AC powered, I would think a better solution would be to purchase one or two more inexpensive monolights instead. These most commonly have built in slave triggers, recycle quickly and put out more light than a typical hot shoe flash unit.

Cliff Henry , Mar 08, 2005; 11:40 p.m.

For Bill Goldman.

Sorry Pierre for hijacking your thread.

Bill, you said metal hot shoe would short out flash! My light stand's umbrella attachment has a metal shoe and I noticed that *all* pins on the foot of my 550EX touch the bottom of the shoe. Could this cause a short in the flash? Should I use plactic stand that came w/550 instead of metal shoe? I am use ST-E2 to trigger flash.



Bill Goldman , Mar 09, 2005; 12:56 a.m.

I don't know if the metal shoe is a problem or not. If you have tried it and it is not a problem and your 550EX still works ok, then I guess it's nothing to worry about.

Bill Goldman , Mar 09, 2005; 01:00 a.m.

Of course, when you use the 550EX as a wireless slave, the connections in the foot of the unit are not active, but if you use it in the camera's hot shoe or in manual mode with an optical slave, the connections in the foot are active.

Jim Strutz - Anchorage, AK , Mar 09, 2005; 02:11 a.m.

My experience indicates that this might not be so simple. All of the optical slave devices I have used (4 or 5 different ones) caused *most* Canon Speedlites I used to fire once then lock up. To unlock you have to turn the flash off/on or press the open flash button. This was true regardless if the other pins on the foot were shorted or not. Oddly, some Speedlites would work fine, but others of the same model number would not. When I found a Speedlite that worked with one slave, it would work with them all.

The one optical slave that I have found to work with all Canon Speedlites is the Ikelite Lite-Link TTL slave. It has contacts for all the pins on the flash foot. You don't have to use it in TTL mode, and it is a very good slave. Adorama sells them for $80.

Bill Goldman , Mar 09, 2005; 02:31 a.m.

The problem of the Speedlite firing once and then locking up is usually due to a polarity problem.

I have a LiteLink and it has a switch on it to prevent this problem. However, the way it works is that it emulates a TTL (master) Speedlite mounted on the camera by turning on the slave when the master turns on and off when the master turns off. It is not compatible with the E-TTL system.

Jim Strutz knows his stuff and if he says it will work as a non-TTL optical slave trigger, I assume he is correct. However, as I understand it, it still emulates the master in that it duplicates the master's flash duration so it is dependent on the characteristics of the master flash and a flash meter is going to be necessary to measure its output and adjust its (manual) power outputin order to control the slave's contribution.

Jim Strutz - Anchorage, AK , Mar 09, 2005; 02:47 a.m.

I hadn't considered polarity. Interesting.

Yes, the Lite-Link still thinks it's a TTL slave device, and I'm sure it is trying to tell the flash to quench when it sees the other strobes stop, but if the Speedlite is in manual mode it just gets tripped and fires at whatever power you set it to. A flash meter is the only way to easily get the exposure correct.

R. Moreno , Mar 09, 2005; 11:32 a.m.

I have used a 540ez and 420ex with Ikelite light links and I rather like the manual control of the 540ez (which I presume the 580ex has) because it is easier to anticipate what the flashes will do when used in multiples. Using the 420ex doesn't allow manual control, so if you are using TTL, it will mimic whatever your flashes do, which is fine if they are all illuminating the same object from the same angle. If you are looking for ratio control, it is a little more difficult. If your strobe system is manually controlled, then the results are a little more predictable when using the lightlink. I have done this myself with two lightlinks with the 540ez on manual as main and 420ex on TTL as fill, both triggered by a ringlight which made no real contribution to the exposure. Plenty of power. With the flashes firing through 42inch umbrellas at 4 feet from the subject on either side about 45degrees from midline triggered by the ringlight (I wanted very soft shadows), I was able to use f/16 stop with 400ASA film as checked with a flash meter. I trusted the meter and the picture came out quite nice.

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