Problem syncing flash

[fogmeister]

I'm fairly new to photography so don't want to throw too much cash at it too soon...

I have a Canon 1000D and a couple of cheap SLR flashes. Both work on the camera hotshoe although I understand this could cause me problems

I bought a slave cell which is activated by the on-board flash so I could try being a bit more creative and put the slave flash about 3' from the subject. When I review the pics the off-camera flashes have had no effect. I've even tried a 1" exp. in a darkened room in case the slave was triggering slowly.

Any ideas, please?

Thanks in advanced

Graham

 

[Catdaddy]

My guess is that the on-board flash is firing just before the exposure, so that the sensors in the camera can make the correct adjustments for the flash... Your trigger cells are detecting this pre-flash and firing off before the shutter gets released.

IIRC, I had the same issue on my D70 when I tried the same thing. The only way around it is to set the on-board flash to manual instead of automatic, so that you only get a single flash... Is that possible on the 1000D?

Hopefully that makes some sense...

 

[fogmeister]

Thanks, Chris, but I think I've already covered that possibility.

I pressed the shutter-release halfway and the on-board and slave fired. I then waited for the slave flash to recharge before pressing the shutter-release fully. Again, no effective light caught from the slave flash...

Thanks again

 

[specialman]

If you put one of the flashes (in full manual mode) on the camera hotshoe, will it fire the other flash with the optical slave attached? If so, there's something going on with your pop-up flash, which sounds too much like a pre-flash to be anything else.... Are you setting the camera to full manual also?

How come the pop-up flash is firing on a half-press of the shutter? The onboard flash should only fire when the shutter is fully pressed....

Pre-flashes happen so quickly they seem to be part of the main flash but they aren't - it's the one thing that puzzles people when using Nikon's CLS system.

 

[HoppyUK]

It's the pre-flash triggering your optical slave too early. You cannot disable this on your camera. The flash does not fire when you half-press the shutter release - perhaps what you're seeing is it functioning as an AF assist light.

There is a workaround to the pre-flash issue. Press the FEL* button, which fires the pre-flash for exposure measurement for use in difficult circumstances (see handbook). The slave will fire, so allow it to recharge. Then when you press the shutter release, only the main flash is fired by the pop-up which will then trigger the slave in sync.

 

[fogmeister]

Guys, thanks for the help. Think I've sort of solved the problem.

As per Specialman's comments - it does seem to be the on-board that is pre-flashing. I put one of the flashes on the camera and the other on the slave. Both fired correctly.

By covering the flash on the hotshoe with card it maximises the off-camera flash and gives the angled lighting I'm looking for.

Just need to sort exposure now but it's looking good.

Thanks again, all