Dumb studio flash question

DJ-S1 · January 17, 2006

I say "dumb" because I have limited information to give you, and yet I'm going to ask the long, dumb question anyway. :rolleyes

A few days after I got my 20D we went over to a friend's house. She's a semi-pro photog and has a backdrop and 2 umbrella-type strobes. Don't know what kind, what brand, or even if "strobes" is the right word... she shoots film only and is thinking of going digital, and therefore we decided to take some shots with my 20D and her lights and see what happens.

So we plug a cord in the flash socket and away we go. No strobes. We play with some custom settings I've never looked at before, nothing works. Pop up the flash and both the flash and the strobes fire. Disconnect the cable, shoot with flash, no strobes. Reconnect the cable, try lots of custom settings, no luck. The strobes only fire if the cable is connected AND the onboard flash fires.

So we figure that's just the way it works, and we happily take a bunch of shots of our kids, etc. On looking at them on the PC though, it's obvious that the onboard flash is messing up the exposures. Shots where she was close to the subjects are too bright, further away are too dark, some of them are perfect.

So here's the dumb question: Is my 20D supposed to be able to fire lights like that without the onboard flash going off? :scratch

Here's one of the better ones we got:

Art Scott · January 17, 2006

Limited info but I would say yes...my strobes (Pauc C Buff's white lighting 5000's) will fire with either the sync cord or by slave action...now if that sync cord is attached to the flash that usually disables the slave trigger...without knowing what strobes she has and if she was removing cord from the strobe unit itself ......

Not being a canon person myself I can't comment on the camera..however my KM A2 has a standard pc connector for standard flash operation and if that will fire a standard flash (vivatar 285) then it will fire a studio strobe also.....might want to go to nearest camera store and try firing a standard non dedicated flash like the vivatar 285 to see if it works or if you have a camera that is malfunctioning.

strobes don't know if a camera is film or digital.........

DJ-S1 · January 17, 2006

Art Scott wrote:

without knowing what strobes she has and if she was removing cord from the strobe unit itself ......

Hey, does that mean if we unplugged the camera but left the "dangling" cord plugged into the strobes, then they wouldn't fire? That would make sense, I guess. But then, what makes the strobes kick off if the cord isn't there? If it just senses the onboard flash and then fires off, that won't help. I was trying to fire the strobes only, without the camera flash at all.

patch29 · January 17, 2006

DJ-S1 wrote:

Hey, does that mean if we unplugged the camera but left the "dangling" cord plugged into the strobes, then they wouldn't fire? That would make sense, I guess. But then, what makes the strobes kick off if the cord isn't there? If it just senses the onboard flash and then fires off, that won't help. I was trying to fire the strobes only, without the camera flash at all.

I don't have a 20D, but it should fire the strobes with a PC sync cable and no on camera flash.

It worked with your on camera flash because the power pack has a slave that is triggered by white light (your flash).

It could be a couple different things, some packs have a selector to choose PC sync or slave to trigger the power pack if it was set to slave it might not recognize the PC sync when it triggers, or it could be a bad cable/tip/connection, or sometimes if it uses a household plug on one end it could need to be reversed.

patch29 · January 17, 2006

You can also purchase a PC sync that will slip into the hotshoe and trigger it from there. A good one will also have voltage protection so you will no accidentally fry any electronics.

Something like this.

(SSHSHS) SAFE-SYNC HOT SHOE TO HOT SHOE Mounts Directly to camera hot shoe and has hot shoe on top for flash Safe Syncs safely reduce any electronic flash source from up to 400 volts to less than 6 volts to the camera sync input. This is absolutely mandatory for all high end and especially all Digital Cameras.

or you can get super fancy and use a radio slave, like a Pocket Wizard.

pathfinder · January 17, 2006

Was the 20D being shot in manual mode, or Av mode or TV mode, or one of the automatic modes??

I prefer triggering studio strobes with a wireless device plugged into the hos show on my 20D, like a Pocket Wizard. This avoids all concerns about voltages through my 20D's flash trigggering circuitry.

I agree that the on-camera flash probalby triggered the strobes via the light flash and not the PC cord that was apparently used.

DJ-S1 · January 18, 2006

Thanks guys. Again I apologize for the lack of info. I'm not sure what was selected on the lights side of things. We were shooting either Av mode or full manual, as I recall. I'll have to go over there again sometime and learn more; it was certainly fun and if I ever scape up $1500 or so I may get a similar set up myself, with the addition of a Pocket Wizard.

Shay Stephens · January 18, 2006

If you shoot with studio lights, shoot manually. There is no reliable way to shoot in a studio setting with auto or semi auto exposure settings.

DJ-S1 wrote:

We were shooting either Av mode or full manual, as I recall.

Dumb studio flash question

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