Bronica GS-1 external flash question

Tom16 · Oct 12, 2021

Hello,

I've been using a Bronica GS-1 for the last 12 months and I was quite recently given a small Vivitar flash by someone as they were clearing their house. I didn't think it would work with the Bronica but I just wanted to check in case I am completely wrong. Here are a couple of photos of the flash.

Thanks!

Tom

Neil Grant · Oct 12, 2021

..if the flashgun is in working order, and you can connect the lead to an x-synch socket on the camera or lens, then it should work. You should be aware that low-cost flashguns, like the one you have been given, typically have very high trigger voltages. Much higher than professional grade versions (like the camera maufacturers own) - and this could damage the electronics in your camera. It's not worth taking the chance.

AgX · Oct 12, 2021

The issue I see may be the synchro switch in the camera.

Ah.. Neil already hinted at this. Any harm though only could happen if that switching is done already by transistor and no longer by mechanical switch.

AgX · Oct 12, 2021

And it is less a matter of cost of the flash, but its age. That Vivitar one still is from the mechanical age so to say.

But yes, putting the little sync capacitator directly to the sync cable safes a bit over adding a low voltage sync circuit.

Dismayed · Oct 12, 2021

Older Vivitar flashes have high trigger voltages. You might want to check to see what's safe for your GS-1.

wiltw · Oct 12, 2021

The GS-1 has a mechanically actuated synch for flash, it is fully safe to trigger that Vivitar with the GS-1 sync circuit. The shutter is TIMED by electronics in the body, but the shutter is a Seiko mechanical shutter that only gets its 'close' signal from the body electronics.

Truzi · Oct 12, 2021

I've used an old Vivitar on my GS-1 with no issues, though not the same model Vivitar. Every now and then a dedicated GS-1 flash comes up on ebay, and I eventually got one.

AgX · Oct 12, 2021

wiltw said:
The GS-1 has a mechanically actuated synch for flash, it is fully safe to trigger that Vivitar with the GS-1 sync circuit. The shutter is TIMED by electronics in the body, but the shutter is a Seiko mechanical shutter that only gets its 'close' signal from the body electronics.

I thought so too, but was not absolutely shure, and thus one better stays on te safe side. Actually any film camera shutter is mechanic as such. And thus could take a mechanical switch. Which even would be more precise as being actuated by the shutter itself and thus inherently compensate for any shutter lag. The idea of a electronic switch seems not only the idea to avoid any wear but moreover to reduce cost as no longer adjustment was necessary. What do you think?

MattKing · Oct 12, 2021

According to this link, that flash may have trigger synch voltages in excess of 200 volts: http://www.botzilla.com/photo/strobeVolts.html
A camera/lens like a GS-1 with a mechanical synch circuit may not be damaged by a high synch voltage, but that synch voltage may contribute to the camera/lens requiring service - synch circuits can build resistance through use over time.

wiltw · Oct 12, 2021

AgX said:
I thought so too, but was not absolutely shure, and thus one better stays on te safe side. Actually any film camera shutter is mechanic as such. And thus could take a mechanical switch. Which even would be more precise as being actuated by the shutter itself and thus inherently compensate for any shutter lag. The idea of a electronic switch seems not only the idea to avoid any wear but moreover to reduce cost as no longer adjustment was necessary. What do you think?

Unfortunately that isn't true, the Canon film EOS lineup transitioned to the electronic sync circuit which is vulnerable to flash units frying the synch circuit unless the flash had<6V, and that did not change until the year that the digital EOS 20D was launched. Similarly, other brands of cameras adopted similar electronic sync circuits, so the flash vulnerability lasted for more than a decade. Even the Fuji GW645 manual specifically warns about high voltage

AgX · Oct 12, 2021

You misunderstood. Any of our film cameras has a shutter that is mechanical, by moving blades or curtains, typically moved by a spring. And any such mechanism can activate a switch, down to just one contac leaf. And for decades it was done this way.
My point was why that was changed in the 80's.

wiltw · Oct 12, 2021

AgX said:
You misunderstood. Any of our film cameras has a shutter that is mechanical, by moving blades or curtains, typically moved by a spring. And any such mechanism can activate a switch, down to just one contac leaf. And for decades it was done this way.
My point was why that was changed in the 80's.

Probably the same reason that a number of other stupid choices were made by camera manufacturers...economy of manufacture. By putting the electronic trigger circuit in the same chip as metering and auto exposure logic, they could eliminate a few mechanical parts and save pennies. That's why they got rid of mirror lockup on consumer grade SLRs, originally! And now no PC sockets in lower end dSLRs.

mcrokkorx · Oct 12, 2021

Given this tiny innocent-looking flash has been verified to have an insanely high trigger voltage, I personally would not risk using it on ANY electronic camera. IIRC, Popular Photography and other film-era publications occasionally warned against this: many cameras with electronic shutter systems (esp those with additional proprietary TTL flash contacts) were poorly insulated against stray voltage leaking from the flash triggering. Repairs and service for the Bronica GS-1 and its lenses is extremely difficult to come by today: I'd recommend looking for a similar, inexpensive but brand-new low-voltage flash instead. I could be wrong about this issue, but a new flash is a cheap insurance policy either way.

wiltw · Oct 12, 2021

mcrokkorx said:
Given this tiny innocent-looking flash has been verified to have an insanely high trigger voltage, I personally would not risk using it on ANY electronic camera. Popular Photography and other film-era publications occasionally warned against this: many cameras with electronic shutter systems (esp those with additional proprietary TTL flash contacts) were poorly insulated against stray voltage leaking from the flash triggering. Repairs and service for the Bronica GS-1 and its lenses is extremely difficult to come by today: I'd recommend looking for a similar, inexpensive but brand-new low-voltage flash instead. Cheap insurance policy.

Or get a Wein Safe Sync and put it between the flash and your camera!

AgX · Oct 12, 2021

mcrokkorx said:
Given this tiny innocent-looking flash has been verified to have an insanely high trigger voltage, I personally would not risk using it on ANY electronic camera. IIRC, Popular Photography and other film-era publications occasionally warned against this: many cameras with electronic shutter systems (esp those with additional proprietary TTL flash contacts) were poorly insulated against stray voltage leaking from the flash triggering. Repairs and service for the Bronica GS-1 and its lenses is extremely difficult to come by today: I'd recommend looking for a similar, inexpensive but brand-new low-voltage flash instead. I could be wrong about this issue, but a new flash is a cheap insurance policy either way.

Interesting point. Never thought of this and never read about it.

Anyway, used flashes are dirt cheap, including low sync voltage models.

AgX · Oct 12, 2021

By the way, the AE-1 was the first camera with digital control of its functions, thus basically succeptible to voltage damage, and it got proprietary contacts on the hot shoe.
Thus basically a candidate for stray-voltage damage.

wiltw · Oct 12, 2021

AgX said:
By the way, the AE-1 was the first camera with digital control of its functions, thus basically succeptible to voltage damage, and it got proprietary contacts on the hot shoe.
Thus basically a candidate for stray-voltage damage.

I found a thread on another forum, and one person said, ". I do not use any flash without measuring the voltage first. I am pretty sure that the A1 and T90 use a solid state switch (electronic) but I am not sure about the AE1-P. The others - AL, F1,FTb etc are mechanical."
and another responded, "I have blown up the electronics of 2 A1's so far by 2 different flash guns.
The A1's are beyond repair. At least Canon will not maintain them and an independant repair facility couldn't.
I still have 2 other A1's which I will not use with flash."

itsdoable · Oct 12, 2021

The film cameras from that era can take the ~250V flash trigger, many professional studio units still in use would trigger up around ~$300V, and all these cameras had to be compatible.

Low voltage triggers started happening when computerized programed exposure mode started to appear, the high voltage spike going through the dedicated wires in the camera would induce a large EM spike that affected the low voltage logic circuits. However, there is always a chance that the high voltage spike could arc (or short, due to worn insulation) or induce damage on an old logic circuit (that may be getting marginal from age). With the abundance of old used flashes with low voltage triggers that cost relatively little, it does not make sense to use that old high voltage triggered flash on anything but an old all-mechanical camera. Even then, having that flash unit lying around - you (or someone else) might accidentally attach it to something sensitive (like a digital camera in a pinch), and it only takes one arc.

I have an old Vivitar 283 (~$15). They had trigger voltages from 250V (~1970) to 5.5V (~2000) in it's 30+ year history, The one I have has a trigger voltage of 9.5V. Works great on everything. As long as you don't want TTL.

AgX · Oct 12, 2021

wiltw said:
I found a thread on another forum, and one person said, ". I do not use any flash without measuring the voltage first. I am pretty sure that the A1 and T90 use a solid state switch (electronic) but I am not sure about the AE1-P. The others - AL, F1,FTb etc are mechanical."
and another responded, "I have blown up the electronics of 2 A1's so far by 2 different flash guns.
The A1's are beyond repair. At least Canon will not maintain them and an independant repair facility couldn't.
I still have 2 other A1's which I will not use with flash."

Our fellow erred. The A-1 and AE-1 got a mechanical switch. Even the adjustments of their leaves are described. I have no doubt that the same applies for the rest of the A-family

But now the big surprise:

The Canon T90 has got NO electronic sync switch. There is a mechanical switch within the shutter mechanics.

wiltw · Oct 12, 2021

AgX said:
Our fellow erred. The A-1 and AE-1 got a mechanical switch. Even the adjustments of their leaves are described. I have no doubt that the same applies for the rest of the A-family

But now the big surprise:

The Canon T90 has got NO electronic sync switch. There is a mechanical switch within the shutter mechanics.

That makes you wonder about the guy who stated that he fried two A-1 bodies.

itsdoable · Oct 12, 2021

AgX said:
Our fellow erred. The A-1 and AE-1 got a mechanical switch....

... Canon T90 has got NO electronic sync switch. There is a mechanical switch within the shutter mechanics.

...And this is true for all (almost all) the digital cameras to date - because they have a mechanical first curtain, they has to be a sensor to detect when that curtain is open - which is a switch. However, the flash trigger voltage does not have to shunt through that switch... but almost every film camera did it that way.

Oh, and damaging A1's with a high voltage flash trigger... that did happen. Even if the flash trigger is a separate mechanical circuit, that spike going through the camera next to the logic circuits isn't always benign.

craigclu · Oct 12, 2021

FWIW, After some discussion in a thread related a while back, I tried my Godox rigs (685's and 860, Fuji) set to auto mode on the GS-1 winder flash shoe and it worked fine. I have plenty of old Metz, Braun and Osram legacy rigs with a single pin and they all work fine, as expected so I'll avoid the Godox for general use. I just mention this as most of us have dedicated rigs for our modern digital systems and I would guess most would adapt to Bronica duties and have modern, lower synch voltages, too. A number of flashes on the old Botzilla list were tested by me and I was quite amazed at some of the results, especially what seemed to be innocent looking compact flashes. As someone mentioned, the older 283's were high but the later generation 283 units were quite tame. It's easy to check with a voltmeter.

moto-uno · Oct 12, 2021

+1 For the Wein device . Worked great on my Mamiya 7 . Peter

AgX · Oct 12, 2021

itsdoable said:
...And this is true for all (almost all) the digital cameras to date - because they have a mechanical first curtain, they has to be a sensor to detect when that curtain is open - which is a switch. However, the flash trigger voltage does not have to shunt through that switch... but almost every film camera did it that way.

Oh, and damaging A1's with a high voltage flash trigger... that did happen. Even if the flash trigger is a separate mechanical circuit, that spike going through the camera next to the logic circuits isn't always benign.

So this elecronic sync switch is a myth? And it s "just" about the risk of high trigger voltage going astray?

flavio81 · Oct 12, 2021

wiltw said:
The GS-1 has a mechanically actuated synch for flash, it is fully safe to trigger that Vivitar with the GS-1 sync circuit. The shutter is TIMED by electronics in the body, but the shutter is a Seiko mechanical shutter that only gets its 'close' signal from the body electronics.

... and...

The flash contact itself is in the lens. If it fails for any reason, try other lens.

Bronica GS-1 external flash question

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