Other Collected Information
Table of Contents
The normal style of strobe flash (including all those listed here) varies light output by reducing the duration of the flash pulse. Flash duration is important for two reasons. First, a pulse longer than the time the shutter is completely open is partially wasted. The camera's shutter sync speed (¹⁄₁₈₀th of a second, for current Pentax dSLRs) is the absolute limit for this, but if the flash pulse can't keep up with even slower shutter speeds underexposure will result. Second, when using a flash as the primary light source, shutter speed is irrelevant for purposes of freezing motion, and only flash duration matters.
A flash pulse is a curve, not a straight on-off thing. This makes measuring flash duration tricky, and so it's done in a tricky way. The standard normally used is the T.5 time, which is the time in which the light output is at least half of the brightest level. This number isn't particularly helpful for any practical use, but can serve as a standard for comparing between different models.
Another measurement is the T.1 time: time in which the light output is above 10% of the peak. This comes much closer to representing the meaningful duration of light output. A rule of thumb is that T.1 duration is approximately three times the T.5 time, but there's no absolute correlation.
Pentax provides no duration information for the AF200FG, but for lists the T.5 time for both the AF360FGZ and the AF540FGZ as approximately ¹⁄₁₂₀₀ seconds at full power and ¹⁄₂₀,₀₀₀ seconds at minimum power. Unfortunately, Pentax customer service was unable to provide more detailed information on request. It's a bit odd that the same numbers are repeated for both flashes, since not only does full power vary greatly between them but also minimum power is ¹⁄₃₂ of full in one case and ¹⁄₆₄ in the other. We can estimate that the T.1 time is about ¹⁄₄₀₀ seconds at full power and that stopping-power goes as short as ¹⁄₆₀₀₀ with less-powerful flashes, but it doesn't seem safe to extrapolate too much from these numbers.
Sigma simply states that the flash duration for full-power firing is about ¹⁄₇₀₀ seconds. No details are provided, but it seems safe to assume that this is the standard T.5 measurement, which would put the T.1 speed at around ¹/₂₃₃ seconds — give or take. My request for more details was declined — "I spoke with our corporate office regarding this issue and unfortunately we cannot provide you with privileged information to you as it is not available at this time. We apologize for the inconvenience."
Promaster claims a duration range of ¹⁄₁₀₀₀ to ¹⁄₃₀,₀₀₀ seconds, and Tumax says ¹⁄₁₀₀₀ to ¹⁄₂₀,₀₀₀ seconds. Again it seems unwise to extrapolate much from this beyond the guess that this refers to T.5 time.
There are reports that the Tumax DPT3 series underexposes when a full charge is needed; this may be a symptom of a too-long flash duration at maximum power.
Metz does not provide T.5 times at all, but instead gives full tables of T.1 durations at each power level stop. The tables are not identified as such, but Metz customer service confirms that this is the measurement method used. This is excellent news, since T.1 is the actually-useful number. The ranges given are as follows:
- 44 AF-1: from ¹⁄₁₂₅ seconds at full power to ¹⁄₁₅,₀₀₀ seconds at ¹⁄₆₄ power
- 48 AF-1: from ¹⁄₁₂₅ seconds at full power to ¹⁄₂₅,₀₀₀ seconds at ¹⁄₁₂₈ power
- 50 AF-1: from ¹⁄₁₂₅ seconds at full power to ¹⁄₂₅,₀₀₀ seconds at ¹⁄₁₂₈ power
- 52 AF-1: from ¹⁄₁₂₅ seconds at full power to ¹⁄₂₅,₀₀₀ seconds at ¹⁄₁₂₈ power
- 54 MZ-4i: from ¹⁄₂₀₀ seconds at full power to ¹⁄₂₆,₀₀₀ seconds at ¹⁄₂₅₆ power
- 58 AF-2: from ¹⁄₁₂₅ seconds at full power to ¹⁄₃₃,₀₀₀ seconds at ¹⁄₂₅₆ power
The reduced-power numbers are significantly faster than anything available from the other manufacturers. This is partly because Metz's flashes allow several stops more latitude in reducing flash power than the competition.
At the other end of the scale, though, there is a concern that the flash duration of the AF models at full power exceeds the ¹⁄₁₈₀ second sync speed. Metz technical support confirms that when full flash is necessary, the shutter speed must be kept below the listed duration. However, it should be noted that Metz is the only maker to give solid numbers on this at all, so I would be careful about holding this against them unless we can get better real data from anyone else. Also, when the flash is used as the primary light source, my K10D in P mode prefers to set the shutter speed to ¹⁄₆₀ with any P-TTL flash, well within the safe range.
Metz does not provide a detailed chart of flash duration for the 36 AF-4 and other more-basic flashes, probably because without manual control that information would be of little use. The duration is listed as ¹⁄₅₀₀ to ¹⁄₃₀,₀₀₀ seconds, and Metz technical support confirms that this is indeed the T.1 number — the tech even tested in the lab to double check at my request. (The T.5 duration is about ¹⁄₁₀₀₀.)
The T.1 timing data can be used in combination with guide number information to calculate the maximum distance at which one can freeze motion to a given duration. The following chart is for ISO 100 at f/2.8. Multiply the distance by √2 in order to increase ISO or aperture by one stop or conversely divide to go the other direction. It assumes maximum zoom.
Again, please remember that this is based on manufacturer-published data rather than on actual measurements. There's really not going to be any useful way to calculate this without careful hands-on testing and an oscilloscope.
The ✖ indicates a very rough approximation of the range and duration of the Pentax AF540FGZ at minimum power based on the given T.5 number. (The AF360FGZ estimate is about a tenth of a meter less, and therefore basically in the same approximate range.) This is really just an educated guess, and I only include it at all because Pentax-branded equipment is obviously of particular interest.
1 Non-rechargeable AA Lithium cells. Rechargeable lithium batteries are not supported.
2 both Super and ST models.
Keep in mind that these numbers represent the worst case: time to recover from a full discharge. A more powerful flash will need a smaller portion of full charge for a given level of light and will be correspondingly faster in practical use. On the other hand, recharge times will increase as the battery drains.
Size and Shape
Although all flash makers list the height, width, and thickness of their flash units in the manuals, the fact that flashes are not actually cubical makes these numbers not particularly useful on their own. All of the flashes bulge in different directions, and there's different degrees of narrowing near the base. The Metz 48 AF-1 is nominally smaller than the Sigma EF530-DG, but it's fatter, so it doesn't necessarily take up less space in practice. Plus, some companies seem to give the dimensions in the tilted-forward configuration, and others with the flash straight up.
The important thing is: only the very basic Pentax AF200FG, Metz 24 AF-1, and Tumax DSL28 series are really small. The Pentax AF360FGZ and Metz AF 36 AF-5 might qualify as compact, but the others range from large (Metz 44 AF-1) to quite large (Pentax AF540FGZ, Metz 58 AF-2, Sigma EF610 DG).
This list shows weight with four NiMH rechargeable batteries (about 110g). The manuals list the weight without, but since they all use the same batteries and since a flash without power isn't much good, this is more useful for comparison. The values also include any required modules.
- Tumax DSL28AF: 180g
- Metz 24 AF-1: 180¹
- Pentax AF200FG: 300g
- Metz 36 AF-4/AF-5: 315g
- Promaster 5250DX: 330g
- Promaster 5550DX: 360g
- Promaster 5750DX: 360g
- Tumax DPT5AFZ: 360g²
- Promaster 7200EDF: 365g
- Pentax AF360FGZ: 380g
- Tumax DPT3AFZ: 380g
- Promaster 7400EDF: 395g
- Sigma EF-530 DG ST: 415g
- Metz 44 AF-1: 415¹
- Sigma EF-610 DG ST: 430g
- Sigma EF-610 DG Super: 440g
- Sigma EF-530 DG Super: 445g
- Metz 48 AF-1: 450g¹
- Metz 50 AF-1: 450g¹
- Metz 52 AF-1: 455g¹
- Metz 58 AF-1/AF-2: 465g
- Promaster 7500EDF: 490g
- Pentax AF540FGZ: 490g
- Metz 54 MZ-4i: 550g³
1 The weight in the manual is with batteries (some Metz manuals say erroneously that it is not); this is calculated from the base weight plus 27.5g per battery.
2 Yes, the DPT3 series flashes weigh about 20g more than the more-advanced DPT5 series.
3 This is with the Pentax-specific SCA 3702 module. With the generic SCA 301 module, total weight is about 20g less.
These flashes can be broken into several groups in terms of flash power for the weight:
The smaller flashes like the Pentax AF200FG generally produce less light for their weight than the higher-end models, with a slight edge to the 2-battery units like the Metz 24 AF-1 and Tumax DSL28AF. The absolute size is lower, but you pay for it in power (and likely in recycle times as well.)
The Pentax AF360 and all six Promaster models all rate about the same, as is the Metz 36 AF-4/AF-5 and Metz 44 AF-1. The discontinued Metz 48 AF-1 and 50 AF-1 produce slightl more puch for the weight, and Metz 52 AF-1 a bit more yet.
The older Sigma models and the higher-end Metz 58 AF-1/AF-2 and Pentax AF540FGZ weigh more, but you do get more than linearly-corresponding power and versatility in exchange. The new Sigma EF-610 flashes and Tumax DPT5 series are at the top end, providing the most bang for the weight.
All that said, as the chart shows, though, especially when batteries are considered, there's not really a huge range in the entire lineup. The 2-battery flashes are outliers on the low end, and the big module-based Metz is on the heavy side, but in the middle everything is pretty much the same.
Unfortunately, I don't have the funding to experiment with dropping flashes from heights onto hard surfaces. However, I will make a few surface-level comments. All of these flashes are made of plastic, and even the Pentax-brand modules seem like it, especially when put next to a solidly-built camera like the K20D. The Metz flashes subjectively feel the most solid to me, but this may very well be mostly because of the type of plastic used for the outer casing. The Sigma and Promaster flashes seem a little more flimsy than the Pentax or Metz ones (especially when moving the tilt/swivel heads), but not so as they'll fall right apart or anything.
The new Metz 50 AF-1 and 58 AF-2 models use metal for the flash foot; all others are plastic. Plastic is not necessarily bad, as it's better for the flash shoe to break than the camera's hot shoe, but obviously metal is more durable.
There have been some complaints about the Pentax flashes getting their zoom reflectors stuck and needing to be sent in for service. Research on the web indicates that this is unfortunately common with zoom reflector flashes of all brands (including those from other camera manufacturers), and I don't think Pentax is particularly bad in this regard.
There are also several reports of the hot shoe locking pin getting stuck with Pentax flashes. Sigma and Metz also use this locking pin, and I've seen no equivalent complaints, but it may just be due to a smaller sample size. I certainly found the Pentax locking lever the easiest to use. Metz's more solid feel also carries through here, with the Sigma and Promaster units feeling a bit more klunky to get on to the shoe.
The Tumax flashes are cheaply made and feel like it. Fortunately, they are also cheaply priced. If you're looking to save money, though, note that I've seen many anecdotal reports of these flashes failing within days, so make sure to buy from a reputable dealer.
The basic flashes, of course, have a very basic user interface. The Pentax AF200FG, for example, has an a power switch, a dial for exposure compensation (or manual mode), and test button. Or the Metz 36 AF-4: there's a power switch and a couple of lights, and the zoom setting is changed by just physically moving the reflector. The Promaster 5750DX doesn't have many controls, but does have a old-school mechanically-operating exposure calculator built in.
When you get to the advanced models, there's a lot more possibilities, so the user interface is much more important. As with the interface of camera bodies, this is highly subjective and one person's favorite feature can be another's pet annoyance.
Pentax addresses the problem directly: lots of buttons, switches, and dials. Most only do one thing, and the buttons with multiple features are next to a slider switch which acts as a function shift. There's not really much to complain about.
The interface on the higher-end Metz flashes is likely to provoke the most strongly divided reactions. Rather than having dedicated buttons for each feature as the Pentax flashes do, Metz uses a menu system.This means you never have to remember how to get to a certain feature, because they're all accessed the same way. And, this is why Metz is able to cram in so many little nice touches — they don't need to add a new button for each one. Unlike the Sigma user interface, the operation of each menu function is consistent, so once you learn what each option does, you don't need to learn how to set it. On the other hand, this means making several button presses for most operations. My main complaint is that on the 48 AF-1 (and 50 AF-1) the parameter menu is activated by pressing two buttons simultaneously, and it can't be done easily with one hand. The 58 AF-1/AF-1 works a little more elegantly.
The Metz 44 AF-1, on the other hand, has a very straightforward interface with a small number of elegantly laid-out buttons and lights. None of the controls do anything tricky — the most complicated is that the exposure LED blinks to show that a lens is wider than the zoom reflector can support. There's nothing else non-obvious. This is unique in a flash with advanced features like wireless P-TTL, but the design decision means that some features which the flash nominally supports (for example, rear-curtain sync and modeling light) can't function, and that the wireless mode fires on all channels (since there's no way to input a number).
The Sigma EF-530DG Super and EF-610DG Super have what I find to be an over-cluttered and non-intuitive interface. I had to keep going back to the manual whenever I wanted to do something I hadn't done before, and even operations like setting an EV compensation value are more arcane than they should be. This isn't helped by the way Sigma uses different terminology than Pentax — for example, the HSS mode is indicated by the letters "FP". I had originally assumed that this was due to simply sharing a user interface with the EF-530DG ST but cramming in more features, but in fact the ST version of the flash has a very bare-bones interface, so the blame has to rest elsewhere. (The ST has its own confusing touches, with full power indicated by MH and ¹⁄₁₆th power by ML — "manual high" and "manual low", which is memorable enough once you know but not outstandingly obvious.) Anyway, I'm sure that one could get used to the controls after not very long, but if you use certain flash features only occasionally this may be a real concern, and I found it frustrating.
For some flashes, a wide angle diffuser is a built-in feature. The Promaster flashes don't have that, but the 5750DX and all the 7000-series models include a push-on plastic diffuser in the package. Be aware that this isn't meant to be a light softener or even to provide a bare-bulb effect like a Sto-Fen diffuser — the point is to spread out the flash's coverage for wide angle lenses
A soft carrying case is included with all Pentax and Sigma models, and with the Metz MZ 54-4i and 58 AF-1/AF-2. The Tumax DPT3 and DPT5 flashes usually have this too, but some rebrandings may not.
The Pentax AF540FGZ, Metz 58 AF-1/AF-2, Sigma EF-530 DG and EF-610 DG (both ST and Super), and Promaster 7500EDF models all come with a flat plastic stand to hold the flash on a table or other flat surface for off-camera operation. This is worth mentioning because a stand is incredibly useful for the wireless P-TTL-capable models which don't include it (the Pentax AF360FGZ and Metz 48 AF-1), and getting one separately is more pricey than it should be — see the section on generic accessories.
The Tumax DPT586AFZ includes a stand, but it's not a guarantee that all branded versions of this flash will; make sure to double-check.
The built-in or included diffusers aren't really meant to provide nicer light. They're just there to help cover a greater angle than the widest zoom setting. An optional flash diffuser is generally larger and designed to have a more versatile effect.
Metz makes a couple of flash diffusers designed for their flash units. The Bounce Diffuser 54-23 is a soft, velcro-mounted bounce diffuser that is described as matching all three of the flash units mentioned here and would probably fit on anything. There's also a plastic clip-on diffuser, Mecabounce 58-90 for the 48 AF-1 and 58 AF-1 models and Mecabounce 44-90 for the 54 MZ-4i.
Of course, there are many third-party diffusers like the famous Sto-Fen Omni-Bounce which will fit any of these flashes. However, the 48 AF-1 manual mentions that it automatically detects when the Mecabounce 58-90 is attached and displays a wider focal length automatically — that probably doesn't work with third-party diffusers.
Sigma also makes a bounce reflector designed for their flashes, but which would probably fit on anything of a similar size.
External Power Packs
The Pentax AF540FGZ's recharge time can be improved with the TR Power Pack III, which uses six C-cell batteries.
And the Metz 58 AF-1/AF-2 and Metz 54 MZ-4i can both use Metz's NiMH-based Power Pack P76. They require different power cables, though.
Since the Metz 54 MZ-4i is based on the SCA system of interchangeable modules, it has a whole little universe of add-on possibilities. This would make particular sense if you use multiple camera systems (e.g. also Canon or Nikon) or if you have some of the other SCA-capable Metz flashes.
Promaster's 5000 series is also based on a (different) modular system.
Pentax makes a variety of off-camera flash brackets, hot shoe adapters, and connection cords, which you can see at the Pentax web store. The most interesting one, though, doesn't appear to be marketed in the US — the CL-10 off-camera shoe clip, which is a flash bracket attached via a ball joint to a large clip strong enough to mount the flash anywhere. Oh, and the just-plain-plastic flash table stand is $22 shipped.
Metz makes a wide selection of diffusers, filters, brackets, mounts, and cables, as does Promaster. Sigma's flash stand is the cheapest at twelve dollars, but I think the best bet is Nikon's AS-19 Speedlight Stand, which is designed to either sit on its own or attach to a tripod or light stand — and which is readily available for under $10. I have one and it works very well. The only potential drawback is that Nikon's locking pin goes in a different place than Pentax's, so the pin stays retracted rather than doing its job. The fit seems snug without it, though.
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 flash forum at pentaxforums.com, or ask a question on Photo Stack Exchange.
Quality of Documentation
Metz, Pentax, Promaster, and Tumax all make their product manuals readily-available on their websites. Sigma's US web site does not, but the Japanese one does.
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 for the EF-610 DG ST is two pages of fine print in 12 languages, with some diagrams and tables crammed into the sides. There's not much to it, but even with the flash's minimal user interface, it's helpful to learn that MH means full power and ML means ¹⁄₁₆th power, or that the angle indictor blinking 24mm and 105mm slowly means that the wide-angle panel is in use.
The manual for the EF-610 DG Super is more passable, featuring multiple pages, but is still short on detail, and is 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 Sigma 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.
Tumax has fairly decent one- and two-page manuals available for their flashes. They're short on technical details but do pack in a lot of information. The English translation is awkward but understandable. Many rebadged units simply reprint this, but Cactus has their own booklet-style manuals as well. (They don't say a lot more than the Tumax versions, but are definitely prettier and feature more natural English.)
E-Mail Support Responsiveness
In the course of research for this article, I contacted all of the 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 engineer 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.
For the Tumax flashes, contacting Tumax directly has been fairly effective. Some messages get no response, but others are answered promptly, and those usually with helpful information. I've had no luck getting any response from Sakar, the holder of the Vivitar brand. On the other hand, the Cactus customer support people at Gadget Infinity were both prompt and able to quickly respond with technical information.
On Actually Using a P-TTL Flash
This article is concerned with comparing the available P-TTL options. For information on actually making the most of P-TTL, take a look at OK1000's introductory guide to P-TTL and (particularly if you are having exposure problems) the P-TTL flash guide from Pentax User UK.
Steve Jacob has produced an excellent series of slides called Flash Modes for Pentax. This includes tables showing the results of various combinations of camera and flash settings, and a section called "How PTTL works and what mode to use when".
More Pentax Flash Information
Jens Roesner has a page full of information about the Pentax flash system. Some of it is slightly dated, but even those portions are useful for historical perspective.
I am working on adding pages to this site which will focus separately on information for entry-level, mid-range, and high-end purchases. Hopefully that will help reduce the "drinking from the firehose" feeling the amount of information here can create.
This site was written by and is maintained by me, Matthew Miller. I'm an amateur photographer, and I mostly take pictures of my family. In the dark winters of Boston, a flash is very necessary. I personally use a Metz 48 AF-1 on (or mostly, off, with wireless P-TTL) my K-7.
If you have a flash question not covered in this guide, or need clarification, please post in PentaxForums.com's accessories forum, or on the Photography site @ StackExchange — I'll try to respond there, and if I'm busy someone else will probably provide help before I can. (And it may well be better help — while I've put a lot of effort into gathering information for this site and organizing it into a helpful presentation, there are plenty of people with more flash expertise than I have. And I have a day job.)
Thanks to the members of photo.net, pentaxforums.com, and forum.digitalfotonetz.de for suggestions, corrections, and clarifications. And extra thanks to all the people who continue to contact me with updated information.
Thanks also to the technical and customer support representatives from Pentax, Metz, Promaster, Sigma, Cactus, and Icorp. Metz and Promaster in particular answered a large number of questions in a short time.
28 Jan 2013 22:30
If you copy content from this site, please include my name and the URL of this site <http://pttl.mattdm.org/> as part of the required attribution, properly hyperlinked where possible, as specified by the license. That's my payment; the basic specifications are public domain, but all the writing about them isn't.
Pentax flash images provided by Pentax and used with permission. Metz flash and power pack images provided by Metz and used with permission. Sigma flash images provided by Sigma and used with permission. Cactus flash images provided by Cactus/Gadget Infinity and used with permission.
This site is not affiliated with any flash manufacturer. All trademarks belong to their respective owners.
Please also see the acknowledgments page. While I've put a huge amount of work into this site, it wouldn't have been possible without your help.