[jawats]

All,

I often see flash units for sale at auctions, thrift stores, etc. that run into the X-Sync socket. I'd like to experiment with them and some of the interesting filters that come with them.

Are there voltage limitations / concerns like there are with hotshoe-mount units? Or does the X-Sync regulate that better?

[photoptimist]

Voltage is a significant concern and could damage the K-1's hotshoe or X-sync socket.

The internet does have lists of flash models that seem to be "safe" or "dangerous." However, if you value your camera, then get a voltmeter for checking the flashes yourself or buy a little doodad that provides protection.

Have fun!

[jawats]

Voltage is a significant concern and could damage the K-1's hotshoe or X-sync socket.

The internet does have lists of flash models that seem to be "safe" or "dangerous." However, if you value your camera, then get a voltmeter for checking the flashes yourself or buy a little doodad that provides protection.

Have fun!

Is there a "safe" voltage spec someplace for the K-1?

[jopenmx]

I have used my old Pentax AF-280 T , with both K-10D and K-3, with good results , but of course with limitations , and only in Sv, Tv or P mode. However , in my K-1 never tested the AF-280 T, although in the internet information was described as " safe " . With my K-1 only have used my small Metz M-400.

---------- Post added 11-11-21 at 18:14 ----------

According to the list of "Strobe Trigger Voltages " in PhotoRant: There Are Many Kinds of Pictures ., the value for Pentax AF-280 T is 7,8 Volts.

[jawats]

I have used my old Pentax AF-280 T , with both K-10D and K-3, with good results , but of course with limitations , and only in Sv, Tv or P mode. However , in my K-1 never tested the AF-280 T, although in the internet information was described as " safe " . With my K-1 only have used my small Metz M-400.

---------- Post added 11-11-21 at 18:14 ----------

According to the list of "Strobe Trigger Voltages " in PhotoRant: There Are Many Kinds of Pictures ., the value for Pentax AF-280 T is 7,8 Volts.

Thank you!

[stevebrot]

Are there voltage limitations / concerns like there are with hotshoe-mount units? Or does the X-Sync regulate that better?

Both the hot shoe and the PC sync on all Pentax dSLR are voltage sensitive regardless of exposure mode. Pentax has been coy about the actual upper limit, but Pentax-brand* and recent compatible third-party flash typically measure in at less than 10V. I would be hesitant to exceed that and would definitely use a safe-sync or similar for 20V and over.

FWIW, my high voltage vintage flash (all 70s/80s vintage Vivitar) are kept in a separate location from those I use on my K-3 with a warning on the box top. Those are only used with my voltage tolerant Yonguo RF603N II radio triggers or with my manual focus film cameras that were contemporary with the flash.

Added: A possible response from your dSLR when an over-voltage flash charges on its hot shoe is to simply lockup as a protective mechanism. Immediately turn off the flash and remove it from the camera. Put the camera on/off switch in the off position (may not do anything), remove the battery and set the camera aside for a 1/2 hour or so. After that, replace the battery and with any luck, that will be all it takes.**


Steve

* All with flash names starting with AF are compatible.

** My recollection from personal experience.

[jawats]

Both the hot shoe and the PC sync on all Pentax dSLR are voltage sensitive regardless of exposure mode. Pentax has been coy about the actual upper limit, but Pentax-brand* and recent compatible third-party flash typically measure in at less than 10V. I would be hesitant to exceed that and would definitely use a safe-sync or similar for 20V and over.

FWIW, my high voltage vintage flash (all 70s/80s vintage Vivitar) are kept in a separate location from those I use on my K-3 with a warning on the box top. Those are only used with my voltage tolerant Yonguo RF603N II radio triggers or with my manual focus film cameras.

Added:


Steve

* All with flash names starting with AF are compatible.

Steve,

Thank you! What interests me is the statement "all with flash names starting with AF are compatible..."

So, looking at this list, would it be ANY flash with "AF" is compatible with Pentax, and that does not exceed 10V is likely to be safe for dSLRs?

[stevebrot]

Steve,

Thank you! What interests me is the statement "all with flash names starting with AF are compatible..."

So, looking at this list, would it be ANY flash with "AF" is compatible with Pentax, and that does not exceed 10V is likely to be safe for dSLRs?

Yes, Pentax with AF are safe as is any flash measured at 10V or less.


Steve

[bobbotron]

When in doubt, don't mount to your camera.


Use of a radio trigger is a great option.

[Lord Lucan]

In my experience, most flash unit voltages seem to fall into two distict categories - 10 volts and under, and 100 volts and over, with not much in between. This is because from around 1980 flash unit manufacturers became aware that cameras were becoming increasingly electronic and could not tolerate traditionally high flash trigger voltages, and therefore came to incorporate internal voltage buffering down to a few volts.

In some cases, such as the then popular Vivitar 283, the maker reduced the voltage quietly, without even making any change to the model number (eg to "283 ii").

Note that this general voltage reduction from 1980 was not driven by digital camera tech - later film cameras had sensitive electronics too. Another common fallacy is that the X socket is different (safer?) in some way from the hot shoe (centre) contact - in fact, inside most cameras these will be wired together.

I use my Pentax AF280T, and several other units from the 1980-2000 period, directly on my K-1. I have always tested their trigger voltage first with a digital multi-meter; these are so cheap these days they are almost free, and the AF280T gave 7.8 volts BTW. If anything, a meter will under-read the voltage, but if a meter shows it is high you can be sure it is high, and as I said they tend to fall into two categories.

There is also this massive list of trigger voltage measurements :-

Photo Strobe Trigger Voltages

PS:

or buy a little doodad that provides protection

I've seen those little doodads that cost £60-80, a rip-off that makes no sense unless you are really attached to an ancient high-voltage unit. For that money you could for example buy half-a-dozen Pentax AF160's or 200's, three or four AF280T's, or one or two AF400T's - all safe units. Safe third-party units are even cheaper : I have just bought a Sunpak DX-8R ring flash complete with a dedication module for £9, that would have been about £150 in 1990.

[stevebrot]

Another common fallacy is that the X socket is different (safer?) in some way from the hot shoe (centre) contact - in fact, inside most cameras these will be wired together.

Yep! I can think of several examples. However, in regards to at least my K-3 (and I believe other Pentax dSLRs with PC sync), the PC sync circuit is isolated from the hot shoe. This can be demonstrated by sampling the PC fitting voltage when a charged flash is on the hot shoe and vice versa.


Steve

[Bob 256]

The reason "old" flashes posed a danger is that the full main capacitor voltage was present on the flash contacts. These contacts (2) were shorted together in older cameras with a switch like set of contacts (no electronics involved) closed with the shutter mechanism, and the discharge current passed through the trigger transformer of the flash initiating the main discharge of the flash tube. You would always get the high voltage on the flash contacts in these flashes.

With electronics moving into cameras, cameras started using an electronic-switch which did the same as the mechanical flash contacts but using transistor devices. In earlier cameras, these were fairly robust and could take the high voltage, but as cameras evolved and electronics migrated to integrated circuits, the electronics responsible for the flash triggering became poorly adapted and around the same time, flashes were changing by placing the trigger electronics in the flash itself (which did away with the high voltage on the flash contacts). At some point camera manufactures decided that cameras didn't need to be high voltage safe and started assuming all flashes in use would be the latter kind when, in truth, there were still many of the older style flashes around. It's kind of like new technology where everything runs on 5 volts so power outlets start changing over to 5 volts (USB charging stations), but they didn't change the outlet style and some locations still provide full line voltage. It's a recipe for disaster, so one needs to know what they are connecting their precious camera to in terms of a flash unit. Practically, you can't blame camera manufactures and there really shouldn't be any high voltage present externally on consumer devices.

Bottom line, it becomes well worth testing the flash voltage if there are any doubts at all. Best case, it can temporarily disable your camera but worst case, these voltages are high enough to fry crucial portions of the electronics in a modern camera and then it's not such a good outcome.

[Dale H. Cook]

FWIW, my high voltage vintage flash (all 70s/80s vintage Vivitar) are kept in a separate location from those I use on my K-3 with a warning on the box top.

I don't bother to keep my three Vivitar 283s separate because all three have been modified to put 5VDC on the shoe and the sync socket.

[Sakura]

I use a Wein Safesync so i can still use a Metz 45 CL1 and CT5. It brings the x-contact voltage down to a save level.

https://www.amazon.com/Wein-Products-W990560-SSHSHS-Safe-Sync/dp/B00009UU18?...ntaxforums-20&

[Lord Lucan]

Later Vivitar 283s had lower trigger voltages but you need to be an expert on serial numbers to know which ones, and sellers tend to think you are a time-waster or accusing them of theft if you ask for that sort of detail. The Vivitar 285 HV was an improved 283, having among other advantages* a lower trigger voltage (but not the 285 without the "HV" suffix). Ironically "HV" means "High Voltage" but it is not referring to the trigger voltage, but to the fact that it could work with a high voltage external battery pack, which the plain 285 could not.

I would recommend the 285HV over the 283 to the OP if he is drawn to either of them. There are loads of both on the market and 285HVs sell for around £25 on the UK Ebay, possibly a bit less than 283s (especially if you add in the 283's optional manual plug-in module) as they are less well known

* Zoom-able head, and both manual and auto modes are built-in.