Note: if you came to this page actually looking to get documentation and support, you're not quite in the right place. You may find your answers somewhere on this site, though. If that doesn't help and you're not able to get information by contacting the manufacturer directly, try the unofficial Pentax camera accessories forum at pentaxforums.com.
Quality of Documentation
Metz, Pentax, and Promaster all make their product manuals readily-available on their websites. Sigma has manuals for the older EF-500 DG models but not the current lineup — however, on request they did e-mail me a scanned copy, as did Sakar.
Metz deserves a commendation for publishing the most useful timing data, and providing first-rate documentation in general, both clearly written and clearly translated into English. The 36 AF-4 manual suffers from an attempt to document Canon, Nikon, Olympus, Pentax, and Sony variants all at once. Theoretically this model, which Metz touts as having "likeably easy operation" is simple enough that the documentation isn't really necessary. The 54 MZ-4i is much more complex, though, and its manual suffers the same problem, made worse by the fact that you have to also have the SCA 3702 manual on hand for cross-reference, and even worse by being somewhat out of date. The Pentax-dedicated 48 AF-1 and 58 AF-1 models, though, get current and Pentax-specific manuals.
The Pentax manuals are also good and (unlike those of the other brands) feature many illustrations and diagrams. However, some features are inadequately explained, while other pages seem a waste of paper — like the one with 28 pictures of the LCD panel's zoom indicator showing all the possible numbers.
Sigma's manual is passable, but short on detail, and sometimes comically translated from Japanese. ("The furrow of the subject will therefore be exposed behind the subject,creating a more natural effect.") I also found it the most necessary manual, because the EF-530 DG Super packs a lot of functionality into an arcane user interface and I had to keep referring to it in order to remind myself how to do things.
Promaster produces short English-only manuals which are light light on detail. That's probably okay for the light-on-features models, and even the 7500EDF is straightforward enough that the manual won't be needed terribly often.
The Sakar 952AF/PEN manual is a single sheet of paper with fine print. It's not badly written but is extremely light on specific details — Sakar is the only flash maker to not even provide guide number data.
E-Mail Support Responsiveness
In the course of research for this article, I contacted all five flash makers with a variety of questions. Pentax, Metz, Sigma, and Promaster were all reasonably prompt and helpful.
Pentax tech support is reasonably good, but be aware that they will refuse to answer any questions about camera compatibility with third-party flashes — fair enough. Also, several of my requests for more detail have been met with the explanation that Pentax Japan has not provided the wanted information to Pentax USA. I actually contacted Pentax Japan directly too, but that didn't help either.
The Metz technical support advisor was particularly accommodating, even performing additional testing with an oscilloscope when the data I asked for wasn't immediately available.
Sigma response time seems to vary — some questions were answered right away, and others have yet to get a response.
Queries to Promaster's "Flash Expert" via their web site are met with an automatic e-mail promising a response within 72 hours, and indeed, replies usually came back well before that. These were very helpful for basic questions, but Promaster was unable to provide technical information beyond that listed in the manual.
Sakar sent me a PDF copy of the 952AF/PEN manual on request (about a week later) but has not yet responded to my other questions. None of the other companies selling differently-labeled versions of this flash have responded to my queries. I did have some correspondence with the Canadian importer of Sakar products, and they were able to get a response via Sakar's web contact form, but the answer they got was wildly improbable (a GN sequence almost as powerful as the Pentax AF540FGZ).
