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Old Sep 20, 2007, 9:02 PM   #1
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Is it possible that the trigger voltage of a flash can harm newer cameras? I have 2 older flashes I used with my film camera and now with my K100d, is this just a myth or something to watch for?
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Old Sep 20, 2007, 9:35 PM   #2
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Hi FE4,

Some older film cameras were set up to handle over 300 volts, and some flashes had trigger voltages that high -- most digital cameras can only deal with about 6 volts. I've heard that different Pentax techs have been quoted from 6-30 volts for the DS, and mostly 6V for the K series bodies. From what I've heard, the high trigger voltages don't necessarily fry the camera circuits right away -- it can take a number of shots before the damage becomes apparent, so just because one tries it once, doesn't mean that it's safe.

The best source for trigger voltages on the net is:


If your flash guns aren't llisted, then there are instructions to measure it (or if you don't have a meter, try taking it to a Radio Shack or similar store).

Or you can get a trigger voltage limiter like the Wein Safe Synch.

With the cost of digital bodies, it's just not worth it to take the chance, IMO

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Old Sep 20, 2007, 9:39 PM   #3
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We've also got a stick post on this subject in the Flash Forum now (which basically mentions the same things snostorm just posted).

Trigger Voltage Limits with Modern Digital Cameras

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Old Sep 20, 2007, 11:50 PM   #4
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Thanks guys, that helped. Although the other flash I have isn't on that list.

Anyone know what the Vivitar 840AF Series 1 flash would be?
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Old Sep 22, 2007, 1:51 PM   #5
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Just a note, my old Vivitar 285 flash shows 7.5V, my much newer 285HV shows about 8.3 volts. All indications are that this will work fine with my DS and DL but may be risky on the K-series.

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Old Sep 22, 2007, 2:02 PM   #6
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I've seen a variety of quotes about Pentax models elsewhere. I can remember reading one post claiming that Pentax Germany told someone the hotshoe was designed to handle up to 30 volts. But, that may have only been earlier models.

The ISO standard is actually 24 volts. But, apparently, nobody pays any attention to it (or if they do, they don't want you to know). lol

I've seen that debated a number of times (including here)... whether or not some camera models' hotshoes are really able to handle 24 volt per the ISO standard, even though they claim you should stay at 6 volts (for example, Canon has told customers 6 volts at times but I've seen it argued that they are designed for more).

Personally, I wouldn't worry about it if a flash was only reading 7 or 8 volts. I've got a couple of older Sunpaks that read about that now that I use in a Maxxum 5D (even though I've seen engineers looking at the circuitry claim it's designed for TTL Level).

But, if you want to be safe without using something like a Wein Safe Sync, see what the camera manufacturer tells you (if you can get a response), or stick with the flashes a manufacturer recommends for a given camera.

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Old Oct 29, 2008, 3:54 PM   #7
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I have just joined this list and would like your comments / suggestions.

I liketaking Macro photographs and previously used a Starblitz 1000 macro ringflash on my Minolta 800si film SLR without any problems.

However - I have just bought a Pentax K10D and tried to use the Starblitz ring flash after attaching a hotshoe adapter with PC Sync to the camera. The result being the flash does not fire :sad:.

A friend brought along an old Minolta flash gun, I attached this to the PC Sync adpater and it fired. So I measured the trigger voltage on both flash guns. The StarBlitz was measuring 3.5 V whilst the Minolta measured 40 V.

Is it possible that the voltage of the StarBlitz is too low for the Pentax K10D circuitry to detect and thus it does not fire?

I did click on the link provided on this topic and found the flash gun I use, and someone stated it had a trigger voltage of 6.8V, could it be that my flashgun is faulty?

Best Regards,


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Old Oct 30, 2008, 3:45 AM   #8
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probably not. you can ck this with a meter by crossing the + connector in the middle of the shoe mount and the - inside the shoe where it's pushing onto the hotshoe. that is, when the flash is not mounted and turned on.
i've been told by pentaxUSA that all the cams were designed for voltage topping out at 300v.. pentax EU says 30v, so who knows.. personally, i think staying under 30v would be safe..

also welcome to the forum..
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