Off-brand flashes on Nikon cameras?

[Erik Petersson]

A couple of times I have stumbled upon a statement that Nikons, such as F3, can be destroyed by the use off off-brand flashes, as the voltage of some flashes would be too high for the camera.

I wonder if anyone could comment on this, and explain what the case is.

Thank you in ahead.

[PeteZ8]

Any camera that uses solid state switching for the flash (all DSLR's, most if not all AF bodies, and perhaps some manual bodies with auto exposure) can and will be destroyed by a flash with a high sync voltage.

Back in the early days, the camera sync'd the flash with a mechanical contact attached to the shutter. The mechanical contact did not care if the signal voltage coming though the flash was 1 volt or 1,000 volts. As cameras advanced, the switching duties were assigned to a transistor for better accuracy, and more flexibility, such as rear curtain sync, FP sync, advanced TTL modes, etc. The problem is the transistors are not capable of handling more than 5 or 6 volts, or they can get nailed.

Since for a hundred years cameras and shutters were all mechanical, the flash manufactures often paid little attention to how much power was being fed to the hot shoe or PC terminal. I have heard in some cases, although I cannot confirm, the voltage being up to 600vdc. More realistically, you are likely to encounter flashes with 10-50 volts from time to time. The older Vivitar 283/285's, for example, were fairly high I believe.

If you're using a flash with unknown hot shoe voltage, it's often advised to use a "safe sync" adapter, or optical slave, or radio trigger. Unfortunately all of the above generally cost more than a more modern flash so it's pretty much a wash.

[Erik Petersson]

Any camera that uses solid state switching for the flash (all DSLR's, most if not all AF bodies, and perhaps some manual bodies with auto exposure) can and will be destroyed by a flash with a high sync voltage.

Back in the early days, the camera sync'd the flash with a mechanical contact attached to the shutter. The mechanical contact did not care if the signal voltage coming though the flash was 1 volt or 1,000 volts. As cameras advanced, the switching duties were assigned to a transistor for better accuracy, and more flexibility, such as rear curtain sync, FP sync, advanced TTL modes, etc. The problem is the transistors are not capable of handling more than 5 or 6 volts, or they can get nailed.

Since for a hundred years cameras and shutters were all mechanical, the flash manufactures often paid little attention to how much power was being fed to the hot shoe or PC terminal. I have heard in some cases, although I cannot confirm, the voltage being up to 600vdc. More realistically, you are likely to encounter flashes with 10-50 volts from time to time. The older Vivitar 283/285's, for example, were fairly high I believe.

If you're using a flash with unknown hot shoe voltage, it's often advised to use a "safe sync" adapter, or optical slave, or radio trigger. Unfortunately all of the above generally cost more than a more modern flash so it's pretty much a wash.

This explains the problem. Thanks!
/Erik

[Mick Fagan]

I run F3 and FE2 Nikon bodies and use a Metz CT32 with the G15 handle and the correct Metz adaptor.

With the same adaptors I have used both the Metz CT60 and CT45 in the past, various models of both flashes from a basic one through to full TTL models of flash and what have you.

The F3 adaptor is called the SCA 341 for the standard Metz CT32 whilst I also have the SCA 344 for the CT45 units. I haven't used a Metz flash on the F3 for about 10 years now, so I'm a bit rusty with them.

Mick.

[eddym]

Check here to find tests of trigger voltages for lots of flashes:
http://www.botzilla.com/photo/strobeVolts.html

[Erik Petersson]

Thanks Eddy. I think I will restrict the use of my Sunpak B3000 to my Zenit. The chart is excellent, but I managed to pick up a flash that does not show on it (the Sunpak B3000), so I don't want to take a chance. Well, maybe it could be used with my Nikon FM2, which is a manual camera... Hmm

[epatsellis]

Going from memory all of my Nikon electronic cameras (F3, F4, Fuji S2 and Kodak SLR/n) have a spec of 250v max sync voltage per Nikon. See http://support.nikontech.com/app/answers/detail/a_id/7349/session/L3NpZC8xVUFJZTRSag%3D%3D/kw/voltage/p/19/r_id/116678/sno/3 for info on their digital SLRs.

[PeteZ8]

Check here to find tests of trigger voltages for lots of flashes:
http://www.botzilla.com/photo/strobeVolts.html

Thanks I had seen that link a long time ago and had no idea where to find it!

[RalphLambrecht]

Going from memory all of my Nikon electronic cameras (F3, F4, Fuji S2 and Kodak SLR/n) have a spec of 250v max sync voltage per Nikon. See http://support.nikontech.com/app/answers/detail/a_id/7349/session/L3NpZC8xVUFJZTRSag%3D%3D/kw/voltage/p/19/r_id/116678/sno/3 for info on their digital SLRs.

This must be a typo on their part. They must mean 25V. Hardly any flash has a trigger voltage as high as 250V, but 250V will definitely fry your digital SLR. According to ISO 10330, all cameras must accept trigger voltages of up to 24V. Unfortunately, not all cameras manufacturers stick to that, and flash manufacturers exceed it.

[eddym]

Thanks Eddy. I think I will restrict the use of my Sunpak B3000 to my Zenit. The chart is excellent, but I managed to pick up a flash that does not show on it (the Sunpak B3000), so I don't want to take a chance. Well, maybe it could be used with my Nikon FM2, which is a manual camera... Hmm

I think that somewhere on that same link he explains how to measure the firing voltage of your own flash. It's really easy if you have a voltmeter; just measure across the contacts of the flash as you trigger it. I've tested all of mine, just to be sure.

[Erik Petersson]

You are right Eddy. However, I do not plan to spend money on a voltmeter for which I will not have other use. Better instead to save them for a TTL-flash for my F3, when I stumble upon one.

[RalphLambrecht]

You are right Eddy. However, I do not plan to spend money on a voltmeter for which I will not have other use. Better instead to save them for a TTL-flash for my F3, when I stumble upon one.

Just wait until you get the bill for all these suggestions! :)

[Erik Petersson]

I thought I paid that already. Or was that the heating bill? ;)

[Steve Smith]

must be a typo on their part. They must mean 25V.

I think 250 volts is correct as most flashes in the Nikon F3/4 era would have had sync. voltages a lot higher than 25 volts.


Hardly any flash has a trigger voltage as high as 250V, but 250V will definitely fry your digital SLR. According to ISO 10330, all cameras must accept trigger voltages of up to 24V.

Most DSLRs are o.k. up to 250 volts (my D100 was and I think all subsequent Nikons are rated at 250V too) and many flashes have sync. voltages in the 100 - 200 range.

Before digital appeared, no one even thought about it. They bought a flash and connected it to their camera and used it with no problems.

There is currently some thinking that some DSLRs are only safe up to 6 volts. I think this is largely a myth for two reasons.

First, any competent camera designer would include an opto-triac or thyristor in the sync. circuit. These do not exist with such a low maximum voltage.

Secondly, some people have stated that a high voltage flash is o.k. on a PC connector but not the hotshoe (of the same camera). I think this is nonesense too as they would both either be wired together or have similarly specified circuits.

My thinking is that the manufacturers are dissuading people from using high sync. voltage flashes on hot shoes due to a fear of the centre pin touching one of the other communication pins when sliding a charged flash onto a hot shoe and damaging some other part of the circuit rather than the sync circuit itself being damaged.

It could also be a bit of sales propaganda to get people to buy new 'safe' flashes when they buy a new camera.


Steve.

[Steve Smith]

It's really easy if you have a voltmeter; just measure across the contacts of the flash as you trigger it. I've tested all of mine, just to be sure.

Don't fire it - Just let it charge until the ready light is on and measure it. At the point of firing, the voltage will be (close to) zero as the sync. contacts short out.

Most flashes have a circuit consisting of a high resistance (about 1M) charging a low value capacitor (about 10nF) from the main HV supply. The sync. contacts short this charge into the trigger transformer which produces a high voltage pulse which ionises the xenon in the flash tube causing it to conduct. Unless it is stopped by another circuit (auto/TTL/etc.) it will continue conducting until the main HV capacitor is empty. At this point it will stop drawing current and the HV supply will start to charge the main capacitor again closely followed by the little capacitor in the sync. circuit.


Steve.

[RalphLambrecht]

I think 250 volts is correct as most flashes in the Nikon F3/4 era would have had sync. voltages a lot higher than 25 volts.

Steve

I really don't know but a couple of things don't seem to add up:

1. This website lists a lot of trigger voltages and I can't find a single one at or above 250V. http://www.botzilla.com/photo/strobeVolts.html

2. I'm looking at ISO 10330:1992. It limits electronic flash trigger voltages to 24 V and sets this value as the camera minimum.

Any thoughts?

[eddym]

Don't fire it - Just let it charge until the ready light is on and measure it. At the point of firing, the voltage will be (close to) zero as the sync. contacts short out.

Come to think of it, you're right. What I'm remembering is that it's hard to touch the probes to the pc connectors for a reading without firing the flash. With a shoe mount it's easier. I was checking the pc's on my Sunpak 622 and my Calumet Travellites, and they were always firing accidentally.

[RalphLambrecht]

Don't fire it - Just let it charge until the ready light is on and measure it. At the point of firing, the voltage will be (close to) zero as the sync. contacts short out...

Steve

Would it help to connect the voltage meter to the flash contacts with, let's say, crocodile clamps, and then, give the flash time to charge up before taking a reading?

[MattKing]

FWIW, I had some work done in 2006 on one of my Olympus flashes (3 foot drop on to tile floor = broken shoe) and the repair technician was saying then that they were doing a thriving business repairing digital and newer film cameras that had suffered damage when an older, higher voltage flash was connected.

I had a Metz 202 flash until recently, and the 200+ volt trigger voltage is one I wouldn't even consider using with my Mamiya 645 Pro (my newest camera with a flash shoe or synch socket).

Matt

[John Koehrer]

This must be a typo on their part. They must mean 25V. Hardly any flash has a trigger voltage as high as 250V, but 250V will definitely fry your digital SLR. According to ISO 10330, all cameras must accept trigger voltages of up to 24V. Unfortunately, not all cameras manufacturers stick to that, and flash manufacturers exceed it.

Older studio flash could hit that 250V threshold no problem.