Methods of Triggering Firefly Slaves from Canon Digital SLR

[footleg]

Having just ordered a Canon compatiable Metz flashgun to try on my Canon Digi SLR, I was wondering if anyone else has found an affordable way to trigger slaved flashes from this type of camera. As I understand it, a cheap high voltage trigger contact flashgun can damage such cameras, so a compatible flashgun needs to be used. The Canon models are rather expensive for something which is only going to be used as a masked flash to trigger other flashes. Plus when playing with some borrowed Canon EX flashes we found that they appear to trigger the slaved flashes out of sync with the shutter (some sort of preflash issue?).

I did try a low voltage hotshoe mounted radio trigger which I bought from Hong Kong via Ebay (like this one: http://tinyurl.com/3dpm26), and this worked perfectly at home. But underground it is consistently unreliable. Could be temperature or moisture intolerant? It works find before and after the trip, but has only fired twice successfully underground even in large dry passages.

Has anyone had success with anything else?

 

[Dear Noel Axle]

Is there a reason you can't use the onboard flash to fire the Fireflies?  The onboard flash on both of my cameras works well with the Firefly 3. I have a small Acer and a Canon 350D.    You could do away with firing them automatically and leave the shutter open for a while. Then you need one less firefly too.  AH

 

[ogofmole]

As said above if you are using Firefly 3's then these will work well with your on-camera flash. But if you are using Firefly 2's then just use a longer shutter speed and use any flashgun with a test button to fire the rest of your Firefly 2's and Flashguns.

 

[dudley bug]

Hi,

I have triggered firefly 2s by adding a cheap non dedicated flash (Jessops 150A) to the hotshoe. As ever the flash is covered with exposed film to use this as a trigger. Used this arrangement quite happily on 300D, 350D and 40D. I have found a second way to sync the camera with firefly 2s is to use the Flash Exposure Lock (refer to manual for operation, works like focus lock). Essentially this will separate the preflash and actual flash on the built in or dedicated flashgun. By holding the shutter button halfway down it will give your slave flashes enough time to recharge and be ready to fire on the second flash when you fully depress the shutter button.

 

[footleg]

Is there a reason you can't use the onboard flash to fire the Fireflies?

Yes, my camera has no on board flash! (EOS 5D)

As far as am aware, Canon only rate the hotshoes on all their recent EOS cameras (all the digital versions and the newer film SLRs too) up to 6V. Most cheap flashes put out 100+V on their hotshoe trigger contacts. So I have not risked putting any old cheap flash on my EOS cameras because I don't know if it will fry the camera electronics. So far I have used a cheap Olympus compatible flash on my Olympus digital camera that I usually take underground, but I have not managed to track down a cheap equivalent for the Canon EOS range.

 

[Les W]

Footleg,
can you not build a circuit that operates off the hotshoe but uses an external power supply less than 6v (dry cell battery)?
This could then be used to trigger a normal flash therby seperating the 100+V from the camera hot shoe.
I would have thought it should be easy enough to design for anyone with a bit of electronics knowledge.
Perhaps a project for somebody in CREG? 

 

[Dear Noel Axle]

Hang on, you asked for an "affordable way" to fire them... but you're taking a 5D underground   

Anyway, Les' idea sounds good if you really need it to be automated.
I'm going to go and try Dudley bug's idea as I hadn't ever thought of that_

 

[Darkstar]

The way dudley bug suggested is the way I have been doing it for a while now and I have found it to be quite reliable.

 

[footleg]

Footleg,
can you not build a circuit that operates off the hotshoe but uses an external power supply less than 6v (dry cell battery)? 

This is what I have been planning to do, but do not have time to do so before the next Matienzo trip. The noise problems on my images taken with my usual underground camera (Olympus C8080WZ) are spoiling my pictures of big passage and chambers, so I have decided it is time to take the digital SLR underground (very carefully  :doubt: ). I want to be 100% sure I have a working system as I can't fall back on the old system (too much kit to fly out with). I did just find this on the internet however:

 

[footleg]

Hang on, you asked for an "affordable way" to fire them... but you're taking a 5D underground   

Just because the camera cost a lot does not mean I want to spend unnecessary amounts on flashes which may not even work for caving use!

If you have not seen the following website it gives an excellent overview of the problems and also confirms my suspicions that the EOS dedicated flash systems do fire a preflash:
http://www.botzilla.com/photo/G1strobe.html

The table of flashguns tested for use on Canon EOS cameras does not list the Jessops 150A, so I don't know if it is safe. There is a quote from Canon engineers on the web page that "burnt-out flash thyristors are a common EOS repair task". So I would be interested to hear from any of you using flashes on your EOS cameras and who have a volt meter to find out what voltage you can measure across the flash contacts when your flash is full charged.

 

[footleg]

See also this page http://photonotes.org/articles/eos-flash/index2.html, which includes the following:

Note that the damage to the camera can be subtle and cumulative - simply hooking up the flash and seeing if it works is no guarantee that the high voltage isn?t slowly damaging your camera?s flash circuit

Just spotted this too http://photonotes.org/articles/eos-flash/index.html#disableettl:

analogue optical slave units can be fooled by the E-TTL preflash. The 550EX, 580EX, 580EX II, MR-14EX and MT-24EX let you disable E-TTL via a custom function, but they?re the only Canon Speedlites with this ability. All other EX flash units (220EX, 380EX, 420EX, 430EX) will always operate in E-TTL mode when mounted to an E-TTL-capable camera, even if the camera is also capable of supporting TTL and even though they?ll work in TTL mode just fine on a type B camera. (though the 430EX can also be used in manual mode if you wish)

We did also find out that masking a 550EX flash with black electrical insulation tape for triggering Firefly slave units generates enough heat to melt the tape making a sticky mess of the flash (Sorry bat http://ukcaving.com/board/index.php?action=profile;u=1196!)

 

[francis]

Can't you turn the flash output down in manual mode to prevent melting the tape? I can do that on my Nikon flash.

Francis

 

[Dave]

Who will be carrying all this kit footleg??  :-\

 

[footleg]

Who will be carrying all this kit footleg??  :-\

Are you offering?  :ang:

 

[footleg]

My new Metz flash arrived today, and looks like it might be a bit more difficult to set up than I expected. I thought that by buying the cheapest Canon digital compatible flash I could find it would not support the fancy features I don't need (specifically the E-TTL capability which uses a preflash to assess the correct flash power to use for the actual exposure). The model I found was the Metz mecablitz 36 AF-4 for Canon (Found for ?68 including the postage on Amazon (from seller CameraKing)). Turns out if does support E-TTL, and the only control on the flashgun is an on/off switch! I'll try it out at home tonight and report back. Hopefully I can either turn off the E-TTL mode via the camera, or disable it by blanking out some of the contacts on the hotshoe to fool the flash into reverting to normal TTL mode. Reading the manual, it appears that the mecablitz 36 AF-3 model only supports TTL, which does not have the preflash feature, so maybe that would have been a better bet?

 

[footleg]

After an evening of experiments, I have confirmed that the Metz mecablitz 36 AF-4 for Canon does not work with Firefly2 slave units. It would of course work with the more expensive Firefly3, as these can be programmed to trigger on the second flash, but I don't think that is a good route to go down for mutliple flash work. I often find that the masked flash on the camera does not directly trigger all the flashes, but that some of them are triggered by the other flashes being used. If I had several Firefly3 slaves programmed to trigger on a second flash, then these would be out of sync with the shutter if they did not all detect the preflash and main flash pulses from the camera mounted flashgun. Plus the Firefly3 is twice the cost of the Firefly2.

The Metz mecablitz 36 AF-4 for Canon is however a fully E-TTL supporting flash which works brilliantly for directly illuminated pictures. I might buy a hotshoe extension lead to use it for single flash work. It is by far the cheapest flash I know of which supports this advanced flash exposure control feature on the Canon digi SLRs. I tried masking off all the contacts on the hotshoe except for the trigger contact, to see if I could get the flash to operate in the standard TTL mode which I think it would do on a non-E-TTL camera. But on my EOS 5D is just does not fire. It seems that Canon have made the camera so that it ignores flashes which are not Canon dedicated.

I then measured the trigger contact voltage on a Vivitar 736AFC flash which I got cheap on Ebay some time ago, and was surprised to find it was only 4.5 volts. It turns out this is a fully didicated flash for the Canon film EOS SLR range, but most sources I have found on the internet say it is not compatible with the digital SLRs. However I assumed it would be safe to try it on the camera as is only has Canon compatible contacts, and a low trigger voltage. With the camera in auto mode it does not detect that the flash is present, and tries to set the shutter speed to cope with the available light (i.e. a long exposure). But set the camera to manual mode and set a shutter speed of 1/125 s and the flash fires fine, triggering slaved flashes in sync with the shutter (easy to confirm by taking a picture of one of the slaved flashes and see if the glare of the slaved flash is captured in the picture). So this is a definite working combination for the EOS 5D with Firefly2 slaves. Pity it is such a big flashgun to carry just to trigger the slaves. Maybe I can build a clip on mask for it so I can use it on camera for quick grab shots too. I'm sure Dave will help me carry everything

 

[prahja]

I use a Wein Safesync... does what your circuit describes.
Not cheap though (~?30)

A.

 

[biffa]

Try cheap ebay wireless triggers.  If you look through the description you can find one with a fire voltage of 6v.  Does require cutting the cable on the firing unit/receiver and soldering on a plug suitable for use with your flash.  Works well on my Canon DSLR with a reliable range of about 30m.  Cost about ?15.

 

[footleg]

Try cheap ebay wireless triggers.  If you look through the description you can find one with a fire voltage of 6v.  Does require cutting the cable on the firing unit/receiver and soldering on a plug suitable for use with your flash.  Works well on my Canon DSLR with a reliable range of about 30m.  Cost about ?15.

Which model are you using biffa? I tried the one which I put a link to in my original post on this thread, but it did not work properly underground.

 

[biffa]

The one I bought:
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=160191192683

Same seller no longer has them described as such but there are some others that look identical and cost the same.  Make sure that they specify a 6v fire voltage so as not to harm your camera.