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Extending the range of the PocketWizard FlexTT5 and 580EX II - Continued
April 7, 2010: The small, bright 430EX II; introducing the Nissin Di866

Shortly after publishing this article last month, we learned of a potential upcoming addition to the list of options for PocketWizard MiniTT1 and FlexTT5 for Canon shooters wanting to avoid the RF noise problem of the Speedlite 580EX II without giving up its power or features. The option comes in the form of a non-Canon flash unit called the Di866 from Japanese flash maker Nissin (the Di866 itself is designed and built in China). LPA Design is currently evaluating this flash to see if it can successfully be used on top of a FlexTT5.

On a related note, almost all of the messages we've gotten about this article to date have been about the 430EX II. If you've read the preceding page, you'll recall that we spoke about Canon's midrange flash in glowing terms, highlighting the fact it's only about 1/2 stop less bright than the 580EX II throughout the range of each flash's zoom head. We were making the point that it's pretty darn close in output to Canon's flagship Speedlite, even though the 430EX II's diminutive size and lower price would suggest otherwise.

What we wrote about the 430EX II led to numerous emails asking the same thing: is it really that close in brightness to the 580EX II? The answer is yes. If anything we understated how close in power the 430EX II is to the 580EX II by giving a ballpark average, since the 430EX II sneaks up even closer to the brightness level of the 580EX II when comparing the two at each flash's widest zoom head positions. This includes when the flashes are paired up with light modifiers such as softboxes and umbrellas.

In this article update we've included brightness results at each zoom head position so you can see where the output of these two Speedlites is most similar, and where their output starts to diverge. First, an introduction to the Nissin Di866.

Upright: The Canon Speedlite 430EX II, left, Nissin Di866, middle, and Canon Speedlite 580EX II, right. Click photo to enlarge (Photo by Rob Galbraith/Little Guy Media)

Introducing the Nissin Di866 for Canon

The Di866 is Nissin's top shoe mount flash, meant to compete directly with Canon's Speedlite 580EX II in both its output and its capabilities. It offers a guide number of 198ft/60m (ISO 100/105mm), Canon E-TTL II compatibility, a tilt-and-twist zoom head with a 24-105mm range and drop-down 18mm diffuser as well as support for both manual and Canon wireless TTL operation. It has both PC sync and external battery pack sockets and is firmware upgradeable. On paper anyway, the Nissin Di866 looks comparable to Canon's best Speedlite.

Standing Tall: The Speedlite 580EX II, left, and Nissin Di866, right. Click photos to enlarge (Photos by Rob Galbraith/Little Guy Media)

As of this writing LPA Design has not completed their evaluation, nor have they committed to ensuring the Nissin flash will be compatible, though LPA Design's Jim Clark indicates the Canon version of the Di866 (it's available for Nikon as well) is so far playing quite nicely with the FlexTT5 for Canon and that the flash puts out very little RF noise at the U.S./Canada PocketWizard frequencies used for ControlTL transmissions.

Based on LPA's favourable impressions so far, we opted to do some basic testing of its suitability as an alternative to the 580EX II too. Not for general use as an on-camera flash, but rather as a remote on a FlexTT5 exclusively. The thinking is this: if it's as powerful as a 580EX II but enables PocketWizard users to steer clear of the RF noise messiness of the Canon-brand flash, then the Di866 ought to be given serious consideration. Particularly by those who don't find any of the RF noise solutions presented on the previous page to be viable. The fact that it's considerably less expensive than a 580EX II doesn't hurt either.

The following is not a full review of the Di866. We've examined only its range, brightness and recycle speed. Through this process we've developed some initial impressions of the flash, both positive and negative, which we'll touch on as well. But the context is all FlexTT5.

In the Power section ahead you'll find a table showing the output of the 430EX II and Nissin Di866, relative to the 580EX II. The results, as they say, may surprise you. Before that, we look at the wireless range of the Nissin Di866 when attached to a FlexTT5.


LPA Design's oscilloscope-based analysis of the RF characteristics of the Nissin Di866 revealed the flash to emit very low levels of RF noise across most of the frequency band used by U.S./Canada PocketWizards and all of the frequency band used by CE PocketWizards. When it's fully recycled and ready to fire, the Di866 does little to interfere with signals headed to an attached FlexTT5 for Canon.

During recycling, however, the flash's RF noise characteristics change. RF noise levels rise slightly at all U.S./Canada PocketWizard frequencies, but only slightly, and not to a degree that suggests working range would be drastically harmed. At the same time, there is a massive RF noise spike that occur as the flash recycles, one which will kill the working range until the flash is done recycling, but the spike directly affects only Standard Channels 1-16 (344MHz).

The ControlTL Channels, which are the channels that will be used 99.9% of the time to communicate with a FlexTT5 with remote flash on top, operate at 340-343MHz and 345-351MHz and therefore avoid the big but narrow frequency spike, even when factoring in some manufacturing variability of the noise-making component inside the Di866, as well as frequency drifts that can occur when this component is exposed to extreme cold or heat.

There is a much smaller RF noise spike that occurs above 351MHz, but is similarly very unlikely to affect any of the ControlTL frequencies. Plus, 16 ControlTL Channels don't border the RF noise spikes, so it's not hard to reduce the low risk of being affected by the noise spikes down to no risk at all, simply by choosing a channel that's far away from 344MHz.

Armed with this information, we put the Nissin Di866 through the same range test as described on this article's first page, using ControlTL Channel 1, which operates at 340MHz (conveniently, this was the channel we had been using already). The flash passed the range test well, giving a working distance when not recycling that was, at about 630ft (192m), nearly on par with the 430EX II.

Knowing from LPA Design there is a slight bump in RF noise that blankets all U.S./Canada PocketWizard frequencies when the Di866 is recycling, we also tested the range while the flash was sure to be doing that. It's difficult to give a precise working distance, but we can say:
  • At about 630ft (192m) away from the FlexTT5/Di866 combo, and with the flash set to 1/4 power, we could fire the flash for two frames before it was apparent the remote FlexTT5 wasn't seeing the incoming signal any longer. At a closer working distance the Di866 would fire three 1/4 power bursts in quick succession and do so consistently, so about the only explanation is that recycling RF noise was interfering by the third frame when at the longer distance.

  • At about 410ft (131m) away, the remote FlexTT5/Di866 would trigger reliably and consistently, even when recycling (though obviously the flash won't light up if it hasn't recycled enough to fire again).
Here's an aerial view of the range results:


While recycling, the Di866 offers greater range than both a stock and a modified 580EX II. When not recycling - and for how we use remote Speedlites the flash will usually be fully recycled at the moment the shutter button is pressed - the range is just short of the excellent 430EX II.

So far so good then with the Di866. Without jumping through any significant hoops, it should be possible to get plenty of working range from the Nissin flash.


To us, there's no point in considering the Di866 in place of a 580EX II unless the former can deliver at least the same power as the latter. After all, if the Di866's maximum output is less, then you might as well go with the smaller, cheaper and surprisingly powerful 430EX II.

The good news is the Di866 is bright. Its maximum brightness exceeds the 580EX II in fact. It's only by a small margin, and it's partly (but only partly) because the Di866's head focuses the light into a slightly tighter beam at most zoom positions. But, it is brighter. The table below shows the output of the 430EX II and Di866 at each zoom head setting, relative to a 580EX II.

The last two table entries show the relative brightness when the flash is teamed up with Westcott 43" collapsible (shoot-through configuration) and Paul C. Buff PLM 64" Silver (reflective) umbrellas. These two results are perhaps the most telling, since pointing a small flash into an umbrella negates minor differences in zoom heads and drop-down diffusers.


Things to note:
  • The only comparison that's truly skewed by flash head differences is the first one. While the drop-down diffusers of the 430EX II and 580EX II give almost identical coverage and fall-off, the spread of light from the Di866's drop-down diffuser is noticeably less. Nissin isn't trying to pull a fast one here. Its diffuser is rated for 18mm coverage, whereas the Canons are both rated for a much wider 14mm, so the Di866 diffuser's somewhat smaller coverage area is in line with its specifications.

  • The umbrella numbers were generated with the flashes' drop-down diffusers in place, to fill out the umbrella surface as much as possible.
Quite honestly, the only numbers we really care about are those for the umbrellas. It's with light softeners like this that the low power of small flashes (relative to studio units) really becomes apparent. From these results you can see why we don't perceive the 430EX II to be much of a step down from the 580EX II power-wise, while the Di866 is slightly brighter overall than Canon's most powerful flash.

While on the topic of power: if you're attempting to use a Speedlite (or the Nissin Di866) in High Speed Sync mode to shoot with flash at high shutter speeds on your Canon digital SLR, and you need the remote flash to match or overcome bright ambient light, the PocketWizard implementation of High Speed Sync enables brighter maximum output.

At 1/4000 on an EOS-1D Mark III, for example, a Speedlite on a FlexTT5 being triggered from a MiniTT1 on the camera will be about 1.75 stops brighter than Canon's native implementation of High Speed Sync. This is one of the most useful features of the PocketWizard ControlTL system, and among other things allows a Speedlite to act like it's a bigger, more powerful flash than it really is.

A full explanation of PocketWizard ControlTL High Speed Sync is in an
earlier article .

Recycle speed

The Nissin Di866 trails the two Canon Speedlites in recycle speed when each flash is powered by AAs inside only. The numbers below quantify what you'll feel when using the Di866: by today's standards, it recycles somewhat slowly.

Charged Up: The slide-out battery module of the Di866. Click photo to enlarge (Photo by Rob Galbraith/Little Guy Media)

The table shows the full power recycle time, in seconds, for each flash when loaded up with fully-charged Maha Powerex Imedion NiMH or PowerGenix NiZn AA batteries. The former is the long shelf life variant of NiMH (often referred to as Eneloop batteries, though this is actually Sanyo's brand name for them and not the official moniker for this battery type), the latter is the stupendous PowerGenix NiZn, a recent addition to the world of AAs that offers the fastest-available flash recycle times short of connecting an external high power pack.


Nissin makes an external battery pack for the Di866 called the Power Pack PS300. The company claims a full power recycle time of 0.7 seconds when the flash is powered by this pack. With the emergence of the NiZn AAs we've all but stopped using battery packs of any kind, since the NiZn batteries provide a way to get fast recycle speed without resorting to an external power solution. With the Di866, however, the PS300 (or Canon's own Compact Battery Pack CP-E4, which is compatible with this flash) will be a must if you need really quick recycling.


Through the course of testing the Nissin Di866 over the past few days we've noticed the following:
  • The build quality of the flash is good. In overall fit and finish it's on par with the Canon Speedlites, except for the buttons, which have a cheaper feel to them, and the zoom head's motor, which is much rougher sounding.

  • The menu system on the Di866's colour LCD screen is easy to navigate, plus it automatically rotates to match the vertical or horizontal orientation of the flash, which is smart. That said, the screen itself is oddly slow to refresh when making settings changes and it's a bit difficult to read outdoors in bright light. When used on a FlexTT5, however, the behaviour of the screen is mostly irrelevant. Once the flash is in TTL mode and its zoom head adjusted the flash's actual operating mode and power level will be set wirelessly from the camera position in most instances.
Sideways: Back view of the Di866 showing the orientation feature of the LCD. Click photos to enlarge (Photos by Rob Galbraith/Little Guy Media)
  • As mentioned, our interest in the Nissin flash is restricted to remote flash use only. We did, however, slip the Di866 into the hot shoe of a 5D Mark II and shot for an hour or so. This led to some really wacky flash behaviour (significant underexposure, disappearing flash menu items and a disabled PC sync socket), even when the flash was removed from the top of the camera. To restore the flash to proper operation it was necessary to reset it (this is an option in the Di866's menus).

    The Di866 we're testing is loaded with an early firmware version (v1211). There have been a handful of firmware revisions since then, one or more of which were meant to improve compatibility with the 5D Mark II, so it's possible, even likely, that the strangeness we experienced with this flash and camera together will be corrected once it's possible to install newer Di866 firmware. ( Update, April 12, 2010: Nissin has now confirmed that later firmware versions for the Di866 do correct the 5D Mark II problems we saw, and we should be able to install newer firmware soon - see the next paragraph.)

    Nissin is working on a utility that will allow end users to upload firmware into the Di866 from a computer, through the USB port on the flash. A release date for that has not been set, says Bruce Michelsen, National Sales Coordinator at Minox USA, Nissin's U.S. distributor.

  • The Di866 has a thermal cutoff feature, similar to the Nikon Speedlight SB-900. It's meant to shut down the flash for 15 minutes when it gets too warm, usually after being fired several times in a row at high power, to keep the flash from being damaged. We attempted to invoke the thermal cutoff, by triggering the Di866 at full power 10+ times in succession. It didn't kick in before we caught a faint whiff of melting plastic, which we traced to the head's very hot and now slightly warped front panel.

    This might mean the thermal cutoff's threshold is set too high, or perhaps it's measuring temperature within the body of the flash exclusively. Whatever the reason, the thermal cutoff feature didn't do what it ought to have in this case. A description of our flash's mini meltdown has been passed on to Nissin in Hong Kong. If we learn of a correction or workaround for this problem we'll publish it here. ( Update, April 12, 2010: Nissin's response suggests that the thermal cutoff feature is working as intended in their view. Which means that, at minimum, it won't prevent some forms of damage resulting from successive high power flash triggerings.)
Trying the Di866 for yourself

The Nissin flash isn't likely to surpass the Speedlite 430EX II as my primary flash of choice for use with the FlexTT5 for Canon. The Canon flash's combination of size, power, recycle speed, range, cost and goof-proof operation within PocketWizard's wireless TTL system surpasses the mix of strengths and weaknesses the Di866 presents. That said, we do plan to keep one around, for those times when it might be useful to have the extra light it produces, relative to the 430EX II.

If you're encouraged by the range and impressive power of the Nissin Di866, and not put off by the recycle speed or the quirks we encountered, then some time relatively soon you should be able to try out the flash on a FlexTT5 for Canon yourself.

It's not possible yet, because the flash isn't compatible with the FlexTT5's current 5.0 official or 5.008 beta firmware. We've been running a private firmware release to make the FlexTT5 and Di866 cooperate with each other; this firmware is expected to evolve into a public beta release in the weeks ahead, assuming that LPA Design's compatibility testing continues to go smoothly and that no significant changes to the flash's firmware are required as well.

If you own a Nissin Di866 for Canon plus a PocketWizard FlexTT5 for Canon and would like to participate in beta testing of the flash, let LPA Design know via this email link.

Another option

The Metz mecablitz 58 AF-1 is another non-Canon flash unit to possibly consider for use as a remote flash on a FlexTT5. In LPA Design's testing it emitted low levels of RF noise at most PocketWizard frequencies, except for a noise spike at 341.5-342MHz. This noise spike, which is evident whenever the flash is on, recycling or not, will affect reception of PocketWizard channels that operate at or close to the affected frequency range. This means you'll want to avoid ControlTL Channels 3, 6, 17 and 18, which leaves 16 other ControlTL channels clear to receive incoming signals.

Compatibility is also good. In LPA Design's testing, the only function that they found to not be compatible and therefore must be disabled in PocketWizard Utility is the pre-flash boost function introduced in recent versions of the MiniTT1 and FlexTT5 firmware.

Revision History
April 12, 2010: Added information about Metz mecablitz 58 AF-1 compatibility and RF noise

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