Backward compatible ?


Link Posted 02/02/2011 - 10:02
Hello all,

Do Pentax digital cameras need to use the newer digital flashguns, or as with the lenses are they backward compatible with flashguns too ?

I have two K10D's and a perfectly good Metz hammerhead flashgun. I haven't tried the flash on the camera's as I don't want to risk damaging the cameras electronics.

Any advice would be gratefully received, thanks,



Link Posted 02/02/2011 - 10:17
HI Steve also got to consider trigger voltage of your particular model. Sure someone will have a link to a relevant site with details of some testing. Alternatively have a look through some old threads



Link Posted 02/02/2011 - 10:25


Link Posted 02/02/2011 - 10:42
Thanks Alan and John for the quick responses.



Link Posted 02/02/2011 - 10:43
Thanks also to Gareth of course !



Link Posted 02/02/2011 - 14:32
Right, first you need to check the trigger voltage on your Metz. You'll need a multimeter set to measure DC voltage, switch the flash on, let it charge, then touch the positive multimeter probe to the centre pin of the hotshoe connector and the negative to the side contact. Some Metz flashes have lethally high voltages while other later ones are fine, this can even apply to the same model (IIRC early Metz 45 CT-1 units have a trigger voltage in the hundreds while later ones are a lot more sensible).

AFAIK all genuine Pentax flashguns are safe on digital, at least those in the AF series such as the AF160 and later. Those with TTL will not work in that mode, but any Auto modes will work perfectly as they use the flash's own light sensor to decide how much light is needed. You just set the shutter speed, ISO and aperture in M mode to what the flash expects (flash set to A) and shoot, the flash will handle the rest. This goes for the AF160 and AF200S.

Weirdly if you go back a generation before the TTL units you come to the Program flashes - these will work perfectly on your DSLR, if you set both units to P and change the ISO the aperture will be changed to suit the flash's expectations.

Some TTL models are still useful to you such as the AF200T, AF280T and AF400T. These all have assorted manual and auto modes, in fact when using the auto modes they behave like a Program flash. Just don't switch them to TTL as it won't work.

I have tested the following models on my K-m:


All worked, none blew it up. They even illuminate the "flash ready" icon in the viewfinder, just as on my ME Super!

Of these models I would say to keep an eye out for the AF240Z (Program/Auto/Manual modes, has a tilt head with built-in telephoto adapter), AF200T (fixed head but incredibly flexible with two auto modes and variable power in manual) and AF280T (pan/tilt head, two auto, three manual modes).

My other advice would be to avoid anything with "SA" on the end - these are usually program-only and while they will work very well you'll be stuck in point and shoot mode. Same goes for some of the later TTL models. If you're not sure then try searching for a manual for the flash you're considering - you can download these free from a few places and you should be able to figure out what the flash can do.

Shooting the Welsh Wilderness with K-m, KX, MX, ME Super and assorted lenses.


Link Posted 02/02/2011 - 15:10
Thanks Matt for that extremely informative information, your a gent.



Link Posted 02/02/2011 - 18:08
cardiff_gareth wrote:
No is the simple answer! The older *IstD used TTL for the flash so older gund were 100% compatable but after this range and the K10d onwards they used P-TTL which is a different metering system so the TTL will no longer work. You can use the flash gun though in M (manual) where you choice the flash outputs. I also hear some older Pentax guns are reasonable on the A setting but I've never used them so can't comment

Not quite entirely true, the *istDS, *istDS2, *istDL and *istDL2 are all compatible with both TTL and P-TTL. Many older Pentax flash units like the AF400t and the AF280t will work perfectly well in 'Auto' mode and deliver, arguably, better results than the most recent offerings.
“We must avoid however, snapping away, shooting quickly and without thought, overloading ourselves with unnecessary images that clutter our memory and diminish the clarity of the whole.” - Henri Cartier-Bresson -


Link Posted 02/02/2011 - 21:47

Only the ist*D and the DS were compatible with TTL, The L was not and I don't think the DS2 was compatible either.
Pentax Lenses:|DA12-24/f4 ED AL|DA35Ltd Macro|FA31Ltd|FA77Ltd|FA50/1.4|F70-210|FA20-35 f4/AL|A*200/f4 Macro ED|A50/1.7|A50 Macro f2.8|1.7xAF adapter|
Voigtlander|125/f2.5SL Macro APO Lanthar|
Sigma Lenses:|EX DG 100-300 f4|2X & 1.4X TC|
Flashes:|AF540FGZx2|RingFlash AF160FC|
Last Edited by Clarky on 02/02/2011 - 21:47


Link Posted 03/02/2011 - 08:35
Well we're both nearly right! The DS2 does support TTL but neither of the DLs do. I thought the only difference between Ds and Dl was the pentaprism/pentamirror.
“We must avoid however, snapping away, shooting quickly and without thought, overloading ourselves with unnecessary images that clutter our memory and diminish the clarity of the whole.” - Henri Cartier-Bresson -

George Lazarette

Link Posted 03/02/2011 - 19:55
Garters is absolutely right about the older "A" flashguns, which expose from the information provided by their own built-in light meter. I find the old guns are significantly more reliable than the P-TTL guns. Although the latter usually work well, they have a tendency to be blown way off course by reflections. Older "A" guns don't suffer from this at all.

I have three of the old AF-400T hammerhead guns, and they work a treat, as well as lending the photographer a spurious air of professionalism.

Nothing better for weddings, where you are expected to look the part with chunky equipment.

Keywords: Charming, polite, and generally agreeable.


Link Posted 03/02/2011 - 22:10
I still think one of the best tricks you can do with a Pentax DSLR is to take an AF160 (tiny auto flash from late 1970s), clip it on, switch the camera to manual and set the aperture/shutter speed the flash expects, then take perfectly exposed shots with gear from thirty years apart!

As I said above, it even manages to use the extra pin to illuminate the flash ready light.

Shooting the Welsh Wilderness with K-m, KX, MX, ME Super and assorted lenses.
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