Methods of Triggering Firefly Slaves from Canon Digital SLR

[Basher]

Footleg, the flash I use on my 350D, (and used to use on my 300D), is a Canon Speedlite 155A, small and very old.
All masked off with exposed film, and it works a treat with my firefly 2's.
Never really worried about trigger voltages, but then again not had a camera fail on me yet.
Having read this thread I have just measured the trigger voltage though, it is 6 volts!
Do a search on ebay etc and see if you can locate one, mine came free from the neighbor, clearing out his Dad's old stuff.
Hope this helps?

Kind regards,

Basher

 

[footleg]

Thanks Basher, that helps to back up my theory that any film eos compatible flash is the way to go for Firefly 2 triggering from EOS digitals. I'll keep my eyes peeled.

 

[Burt]

I just bought a nikon d40x and have found a similar problem. Delving into the manual I found I can turn off the TTL flash sync and make it manual. This disables the preflash which confuses the optically triggered slaves. Worth a try on the canon?

While on the subject, will a standard multimeter measure the voltage on the flash hotshoe or do I need one that makes an instant "grab" measurement? (have also bought a non nikon flash and all this talk of frying camera electronics makes me nervous)

 

[footleg]

I just bought a nikon d40x and have found a similar problem. Delving into the manual I found I can turn off the TTL flash sync and make it manual. This disables the preflash which confuses the optically triggered slaves. Worth a try on the canon?

Possible on some Canon flashes costing hundreds of pounds, but an expensive way to get a camera mounted flash for triggering slaves. My camera model has not got a built in flash.

While on the subject, will a standard multimeter measure the voltage on the flash hotshoe or do I need one that makes an instant "grab" measurement? (have also bought a non nikon flash and all this talk of frying camera electronics makes me nervous)

Elecrontics experts argue that you cannot accurately measure the voltage with a standard multi-meter. But I have found it is an effective way to tell if the trigger voltage is very high or not. I think for low voltage models the standard multi meter gives a reading which you can rely on to tell if it is within the specifications of your camera (6V on EOS hotshoes). It is the high voltages that you cannot accurately measure. But if the multi-meter reads 100V+ you don't need the exact value to know it is probably not a good idea!

 

[DaveR]

Hiya Footleg.

I use a Metz 20 BC 6 as a trigger. Small and simple, very low profile so your light doesn't hit it. It works fine with a Canon 40D and fires Firefly 2s reliably.

www.ciao.com/Metz_Mecablitz_20_BC_6_Hot_shoe_clip_on_flash__10085438

Hope this helps,
Dave

 

[Rob]

Dave, i presume you cover it over with an infra red filter? oR can you adjust the power right down?

 

[footleg]

Hiya Footleg.

I use a Metz 20 BC 6 as a trigger. Small and simple, very low profile so your light doesn't hit it. It works fine with a Canon 40D and fires Firefly 2s reliably.

www.ciao.com/Metz_Mecablitz_20_BC_6_Hot_shoe_clip_on_flash__10085438

Hope this helps,
Dave

Thanks for that tip Dave. Interestingly, this is the only Metz_Mecablitz_20_BC model which is safe to use. The BC4 and B3 models appear to be high voltage and could damage the camera, but the BC6 is around 5V and sounds ideal.

 

[DaveR]

Yes, I have it permenantly covered with IR filter. I have also put self adhesive reflective tape around the IR filter, so when setting up a shot I can position the back flash and look at the camera and easily see if the subject is obscuring it; it stands out much better than a black camera! I also have the tape on all my flashes for the same reason. A small square on slaves also helps you find them if you put them down. Beware of cavers with the tape on their helmets or bags as it ruins the photo!
Guess I was lucky when  bought the flash, as I didn't know at the time about the high trigger voltage! Mind you, I had a Canon 300d then, so maybe they weren't as sensitive. Would have been somewhat upset to fry the 40d!
Cheers,
Dave

PS; Rob; really loving the LED lit shots, especially the 'bogeyman' projected onto the waterfall.
Footleg; we're in Matienzo at Easter, are you going to be there?

 

[jarvist]

Maybe slightly off topic, but I was interested in building a non-flash-unit trigger for firefly 2 slaves.

My idea was to use a high power IR LED (they can take 1A surge currents, and run off less volts than a single alkaline cell).

As such I believe it should be ok to simply wire the LED in series with an AA bat, and into either a cannibalised hotshoe or PC-connector, using the camera to directly complete the connection. This is for use with manual film cameras (Zenits et al.), so trigger voltages & etc. should not be a problem. The vast current you're putting through the camera may be.

Anyone have any feeling whether this would work?

Does the firefly simply trigger off the leading edge of the IR light pulse, or does it actually look for a characteristic 'few ms' flash-like pulse? Or worst of all, trigger on the trailing-edge?

 

[footleg]

Fireflys will trigger from most TV/video remote controls (I use this to test them at home before packing my kit for a trip). Not sure of the range, I just hold the remote control in front of the firefly and press any button to see if the flash triggers. Allows me to confirm the Firefly batteries are OK and the connecting lead is OK too.

 

[footleg]

Footleg; we're in Matienzo at Easter, are you going to be there?

Yes, I'm there from 8th to 18th. Hopefully with some LED lights for some first experiments with video and still photography too.

 

[potholer]

For an IR pulse using an LED, I would have thought the best method would be having a capacitor and resistor in series across the battery, and firing the IR LED by connecting it to the capacitor.

That allows for a high peak LED current, but keeps the total energy low (if a suitable capacitor value is chosen).
It might also allow the use of a somewhat smaller cell to power the LED, maybe even a small 3V lithium cell, or at least an alkaline N cell.