[KjetilH]

I've used a Chinon S-240 flash on my K100D a couple of times as a makeshift macro flash. Didn't seem to hurt it at all, but I probably won't dare to put it on the K20D. Estimated trigger voltage to around 12,5V with some Ni-Mh which have been put through a month or two of flash usage in my 730AFPK, which is barerly 5V.

[Class A]

Estimated trigger voltage to around 12,5V with some Ni-Mh which have been put through a month or two...

Thanks for posting. In what sense to you mean "estimated"? Just because you weren't sure what was left in the cells?

Any particular reason why you didn't vote?

[philbaum]

I don't think the 6V figure has any significance. Not sure where and why it popped up. Certainly all the new Pentax flashes are below that figure but they are even well below 5V.

Another forum member has used a Vivitar 2500 as well without breaking anything.


That's the kind of success story I was hoping to hear.

Very rarely people seem to manage to get an answer from Pentax staff. But when they do, the answer always is reported to be "<30V".

One forum member's K100D survived >200V a number of times, but that should not be taken as proof that it will survive this on a long term basis.

Maybe what's happening here is that the manufacturers of flashes and flash equipment, who probably are producing the parts under a number of brand names, are trending towards the Canon 6 volt limitation, whether or not some bodies can tolerate much more.

Good to know that we can still use some of the older flashes. But now that i know how, i'm going to check them all for voltage.

[Keith]

It is not a case of what voltage works as you maybe able to flash away happily with a 160v trigger voltage ....until one day it goes "pooffff"

I have accidently used a 120V trigger voltage flash a few times on my Pentax DSLR without a problem but I consider myself lucky.

The current information on the internet seems to suggest the max. is somewhere around 24v - 30v.

My current flashes trigger voltages are 6.5V, 9v and 14v

Regarding the 6v max. ....isn't this the max for Canons???

Cheers
Keith

[Big I]

I asked Pentax, and they said up to 300 volts is safe for the *ist DL. Likeliness is that the same thing goes for the K10D/K20D.
I have personally used 60 volts just fine on my *ist DL, but I haven't tried it on my K10D. You can get a multimeter from a local hardware store for like $7 if you really want to check out a lot of flashes. The voltages will differ, depending on batteries, temperature, etc.

[Lowell Goudge]

You can get a multimeter from a local hardware store for like $7 if you really want to check out a lot of flashes. The voltages will differ, depending on batteries, temperature, etc.

You need to be very very VERY careful measuring flash voltages with a cheap multi meter. I did a test, and posted the results (they are linked to my earlier post.)

Cheap moving coil multi meters put a considerable load on the flash and therefore impact the voltage measurement. Look on the meter, and it should somewhere tell you how many ohms per volt (ie the internal resistance of the meter circuitry for each voltage range)

To be certain you are measuring the correct flash trigger voltage you need to use a digitial volt meter with an input impedance of 20Meg Ohms (20,000,000 ohms)

If you look at my posting, depending on the range you use, a cheap meter will report as low as 15 volts trigger voltage for a flash with a 200 volt trigger.

This is NOT something to be undertaken lightly by a person without a technical background otherwise youo have a real good chance of damaging your $1000 camera to save a few dollars with a cheap flash

[philbaum]

My "new" AF280T arrived from ebay. great little 28 GN flash with auto features that really work.

7.18 max voltage i measured. At that voltage i have no concerns and popped it on my K10D and it works fine.

Actually i was sort of hopeing it would fry my K10D so i could get some sympathy out of my wife for a K20D. Alas, not to be. Works just fine, dang it.

I'm going to limit my flash voltages to 12 volts, not because i'm cocerned about my camera, but because my Cactus trasmitters won't take more than 12 volts.

Best, Phil

[Class A]

Regarding the 6v max. ....isn't this the max for Canons???

Yes, it is -> Photo Strobe Trigger Voltages

[Class A]

According to this thread (sorry, in German) "Wieviel Spannung verträgt die K10D?" Pentax confirmed multiple times a maximum flash trigger voltage of 30V for Pentax DSLRs.

[a200user]

I know I'm late to the party, but just came across this thread and thought that I would add my 4 flash results.
Measurements with a Cen-Tech P37772 DMM (Input Imped. 10 MegaOhm)

Each flash measured with 4 freshly charged Energizer 2300 mAh NiMH AA batteries (Measured at 1.4v each)

(1) For reference I measured the Pentax AF-360FGZ = 2.9v

(2) Vivitar 550FD (M/P/O) GN 80' (ISO 100) = 6.8v
(3) Toshiba ES-30 Auto Flash GN 98' (ISO 100) = 29.0v
(4) Soligor MK-32A Auto Flash GN 105' (ISO 100) = 36.0v

Cameras: Pentax K20D, Pentax K30, Pentax K5 ii(s).

Notes:
I found a Soligor MK-32A AutoThyristor Flash in SalArmy the other day for $1.00. Brand new, in the box, never used. Which prompted me to do some research and start taking measurements.

I already had the Toshiba ES-30, but only used it via the included PC sync cable. You don't need a bracket attachment as the proprietary Toshiba sync cable raises the hotshoe pin away from the contact point on the camera's shoe. After reading this and several other posts I decided to first try it direct to the hotshoe on my oldest camera, K20D. No problem.
Then I tried it on my K30. No Problems.
Today I got really daring and tried it on my K5 ii(s). No problems.

In searching around my Camera gear I found a Vivitar 550FD (TTL dedicated pins for Minolta/Pentax/Olympus). No risk at 6.8v. None of my K's recognize TTL, only P-TTL, but there is some automation available with the Vivitar set in one of the 2 Auto modes. With any K body set to P (Program Mode) the F stop is communicated to and sets the camera aperture accordingly.

My last test was with the Soligor MK-32A measuring at 36v.
No issues with K20D, K30, and K5 ii(s).

I took about a dozen shots with each flash on each camera. I really like the results from the Soligor MK-32A, but since that one also came with a PC sync cable, I will probably no longer connect it directly to the hotshoes after today's trials.

X-sync speed on the K bodies is 1/180th seconds. But with the Auto flashes I found best results with the Cameras in M mode, speed at 1/125 and F stop according to the dials on the flash units when set to the same ISO as the camera. 1/180th shutter speeds yielded underexposed results.

I have found my Pentax AF-360FGZ to inconsistently under expose, more so on the K20D and K30 (using P-TTL mode).

No recommendations should be implied from my results. I'm just adding my data to this poll.

[Lord Lucan]

I found a Vivitar 550FD (TTL dedicated pins for Minolta/Pentax/Olympus). No risk at 6.8v.

Your post made me notice this old thread for the first time. I recently created a table of vintage flashgun trigger voltages Table of Flashgun Data using data from the old Botzilla table because it was showing signs of being discontinued, and data from elsewhere, and I added further info like the guide numbers, exposure modes, and links to reviews.

The 6.8v for your Vivitar 550FD looks on the low side (on Botzilla there are reports of around 4, 5, 7, 8 and 10 volts). For my table I have always given the highest reported voltage (within reason) rounded up to a whole number, and I suspect some of the very low voltages reported on Botzilla and elsewhere, like that 4 volts (in fact an implausibly precise 4.24 volts), were measured using cheap analog meters which tend to pull the voltage down. There are also manufacturing variations, variations as the unit gets older, and of course variations in the batteries used.

I really like the results from the Soligor MK-32A, but since that one also came with a PC sync cable, I will probably no longer connect it directly to the hotshoes after today's trials.

Flash units that have a sync cable as well as a hotshoe sometimes have different circuits for the two. I don't think you were saying that the sync lead might have a safer voltage than the hot shoe, but it is not necessarily so. But there is a commonly held belief that one is safe even if the other is not - I can't remember which way round it is supposed to be. More likely the insertion of a sync lead into the flash unit simply operates a microswitch that transfers the trigger signal line from the foot to the cable.

[a200user]

...
Flash units that have a sync cable as well as a hotshoe sometimes have different circuits for the two. I don't think you were saying that the sync lead might have a safer voltage than the hot shoe, but it is not necessarily so. But there is a commonly held belief that one is safe even if the other is not - I can't remember which way round it is supposed to be. More likely the insertion of a sync lead into the flash unit simply operates a microswitch that transfers the trigger signal line from the foot to the cable.

Correct, I'm not saying the sync lead from the flash unit has a different voltage at all. It is probably the same voltage as the voltage at the hotshoe of the flash unit. What I'm saying is that the Pentax K bodies that have a PC sync socket supposedly have high voltage protection at the PC sync socket that is not present on the K body hotshoe. At least this is what I have read in other posts.

The K20D and K5 ii(s) have PC sync sockets while the K30 does not.

The Toshiba ES-30 Auto Flash definitely does not have a voltage difference between hotshoe and PC sync. I took the foot apart to unjam the center pin of the hotshoe. Somehow it was jammed in and wouldn't make contact with the camera body's hotshoe center contact point. The Toshiba sync connector to the flash unit has the normal male electrical contact pin along with a flat tapered pin. The taper of the flat pin lifts a lever inside the lower body of the flash that in turn lifts the center hotshoe pin of the flash, thus not allowing it to make contact with the camera's hot shoe. This allows mounting of the flash on the body in the manner of a cold shoe while using the PC Sync connector.

Next time I have the Soligor MK-32A out I will attempt to take a measurement from the PC sync cable. But I'm quite sure there will be no difference from the voltage at the hotshoe.

Edit: Here is one of the sources for the 'assumption' that the Pentax K Bodies have high voltage protection at the PC sync socket:

You Tube

You Tube

It is a review of the Pentax K20D by Pentax USA Product Manager, John Carlson. Towards the end of the video (6:55) he talks about the addition of a PC sync socket that was not present on the K10D. He states that the socket has special circuitry built into the camera to protect from over voltage damage from studio lights. Although he doesn't specifically say that the 'special circuitry' is different from that at the hotshoe, it seems to be implied. Then of course, he doesn't define what 'high voltage' is either.

And to add to the confusion, the OP of this thread https://www.pentaxforums.com/forums/125-flashes-lighting-studio/87679-flash-...al-answer.html quotes a Pentax source saying that max trigger voltage is 380v. But it's not clear to me if that is in reference to the Hotshoe, the PC sync socket or both.

For reference, my DMM is a digital multi meter with 10Mohm input impedance. I may check these again using my Tektronix 2236 scope that has an inbuilt DMM.