Author Topic: Flashgun Slave Units  (Read 417 times)

Offline DavidGibson

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Flashgun Slave Units
« on: September 13, 2017, 11:10:18 pm »
Ive just realised that it is 25 years since I designed the flashgun slave unit that became the basis of the Firefly 2 and 3. Where does the time go? I used to sell kits of parts, but I stopped, as it was time-consuming to make the kits. However... Im thinking vaguely of starting up again or, at least, selling the printed circuit board and some of the less-easy-to-find components. But Im a bit out of touch with cave photography now and Im wondering, does anyone still use optical flashgun slaves, or it is all radio-based slaves now?

If there is a demand I might - just might - decide to do a few upgrades that are on my list of things to do, and to make available the re-engineered design(s). Im thinking of a suite of items actually - the original slave unit, the digital camera version, plus a flashgun isolator and a bulb firer.

So... Im just wondering - is there still a demand for these items or have people moved on to using other products?
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Offline rsch

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Re: Flashgun Slave Units
« Reply #1 on: September 13, 2017, 11:14:31 pm »
does anyone still use optical flashgun slaves?

Yes, I do.

Online shotlighter

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Re: Flashgun Slave Units
« Reply #2 on: September 13, 2017, 11:54:28 pm »
Really, 25yrs? I think I've still got some of the thyristors somewhere.
Some would certainly be handy to allow old type flash units (I've got several) to be fired off as slaves from a DSLR. Not sure the modern RF units will cope with the terminal voltages on old flashes. Plus it means the small onboard DSLR flash acts as the trigger "transmitter".

Offline ZombieCake

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Re: Flashgun Slave Units
« Reply #3 on: September 14, 2017, 01:06:51 am »
I'd agree with shotlighter.  I'm a bit paranoid about using old flashes on modern DSLRs or Mirrorless as I'm told they generate a good few hundred volts at the hotshoe contact which will convert the camera to a smouldering paperweight. Also I've a few homemade bulb flashes that are simply a 9v PP3 battery and a momentary switch (works very well for anything from AG3's to PF100's) and I wonder if there would be any nasties using the digital hotshoe to trigger instead. Human flash triggers seem in short supply (they learn too quickly.....).

Offline DavidGibson

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Re: Flashgun Slave Units
« Reply #4 on: September 14, 2017, 09:39:32 am »
Not necessary a "smouldering paperweight". I damaged one of my cameras by attaching a small Sunpak gun to it many years ago. The only symptom, now, is that the hot shoe no longer functions.  Now I use slaved guns with an IR filter over the built-in flash on the camera. That way, the camera is able to trigger the flashguns without its own flash giving any foreground light.

OK... so on two replies, it seems that that the "want" is a flashgun isolator.
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Offline Rob

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Re: Flashgun Slave Units
« Reply #5 on: September 14, 2017, 09:44:33 am »
I only use radio slaves nowadays. In my experience they are cheaper, more robust and more reliable than the FF2, and now can even allow for communication to change power levels on external flashes.

However it's worth noting that radio is not possible if you have no hotshoe on the camera (i.e. most compact cameras). I occasionally use my compact, and if i need an external flash i use one of my cheap Yongnuo flash guns which has a (very poor, but clever like the FF3) optical slave built in. If i had a FF3 i would use that.  :thumbsup:
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Offline TheBitterEnd

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Re: Flashgun Slave Units
« Reply #6 on: September 14, 2017, 09:52:45 am »
Coincidentally I built one of your slaves last week on a bit of Vero board, thanks for designing it, 25 years and still going strong must be a testament to a good design I guess.

To answer your question, many modern flash guns, such as Yongnuos, have built-in optical sensors that will trigger from IR so external triggers are not needed. Cheap radio triggers are widely available but obviously only work on cameras with hot shoes or flash sockets. I guess there could be a small market for people with older flashes and compact cameras with no hot shoe.

BTW  My reason for  building one was because I was messing around with over-driving LEDs to use as a compact flash, with limited success. I also made a few changes, I didn't understand the purpose of R6 (3k3 on the positive side of the battery) so left it off, I swapped pins 5 and 6 to create a positive going pulse and left off the opto-coupler but those changes were specific to my LED application.

Thanks again.

Cross-posted with Rob so said a lot of the same things...
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Online Leclused

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Re: Flashgun Slave Units
« Reply #7 on: September 14, 2017, 09:54:48 am »
"Newer" techniques see the following topic https://ukcaving.com/board/index.php?topic=22107.0
Dagobert L'Ecluse (SC Avalon - Belgium)
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Offline DavidGibson

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Re: Flashgun Slave Units
« Reply #8 on: September 14, 2017, 12:06:35 pm »
I only use radio slaves nowadays. In my experience they are cheaper, more robust and more reliable than the FF2
Could you elaborate on "more reliable"?  Do you just mean that they do not always trigger when they should, or that they fail in other ways, e.g. battery contacts, hot-shoe contacts?
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Offline Rob

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Re: Flashgun Slave Units
« Reply #9 on: September 14, 2017, 12:48:20 pm »
David, it's been a while since i used FF2's in earnest, but i remember transferring over to radio slaves (Yongnuo RF-602) maybe 5 years ago and being very impressed at the time. Very rarely have they missed a fire since, and that includes big caves in Mulu with +100m ranges.

My experience with FF2s was not so good. Maybe we didn't always ensure the direction of the sensor was towards the camera and not into the mud, at the time primarily concentrating on the direction of the flashgun itself. Either way, that extra hassle brings seemingly no advantages for SLR users...
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Offline Antwan

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Re: Flashgun Slave Units
« Reply #10 on: September 14, 2017, 07:20:36 pm »
I use flash guns with integrated radio tx to a controller that sits in the hot shoe and let's you change the power/zoom ofindividual flash guns without having to shout at your flash monkeys. Very useful when your flash monkey is on rope (as per the bcra review cover shot.

I have never had a need to use optical in the last few years.