 Robert Lazenby |
Using PD cord with flash Hello, I am trying to set up a multi-flash configuration with my Canon 20D, 580EX and a non-Canon flash. I recently purchased a PC cord and adaptor. When I hook up my 580EX with the cord as a test, the flash fires full power (not able to use the TTL function). What is the best way to set this up and have some control over the amount of power from the flash. I dialed down the 580EX -3 stops and it didn't seem to make much difference. Thanks for any help you guys can offer. Robert Lazenby
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Jon Close |
You don't need to to use an adapter. The 20D has a PC sync cord socket built in. Connect the non-TTL flash to the sync cord, plug the cord into the 20D, and mount the 580EX in the hotshoe. See pp. 10 and 98 of the 20D manual. The 580EX will work in E-TTL and the other flash will fire when the shutter opens. Note that this may give overexposure (depending on how the non-TTL flash is set and positioned) since the E-TTL calculation will not include the light from the other flash.
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Jon Close |
P.S. More generally... The PC sync cord and adapter do not carry the additional wiring needed for full camera/speedlight communication, just the single center firing pin only. So if the 580EX is connected that way it will only fire at full power. If you adjsut the Flash Expsosure Compensation (FEC) on either the 20D or the 580EX it will have no effect because without the communication the speedlight has no baseline for the exposure. However, you can adjust the output of the 580EX by setting it to Manual Flash Output mode (M mode, p. 22-23 of the 580EX manual). The fixed output can be set anywhere from full (1/1) to just 1/128 of full power in 1/3 stop increments.
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Suzanne Colson |
Check out this site/blog. It helped me considerable in understanding flash and all it capabilities: http://www.strobist.blogspot.com/ Good luck!!!
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