Inexpensive Radio-carried iTTL – the AK-TTL (Nikon) by Aokatec

Do you want inexpensive Nikon CLS that works through walls, in bright sunlight, and across a field?  Of course you do.  You might even need it. For off-camera flash I use either manual triggers, or Nikon CLS with an SU-800 or camera-mounted Master flash. And I experience the usual limitations. Manual triggers may require time-consuming trips to flashes to adjust power, and don’t do TTL (which is helpful in dynamic situations like events). CLS is great in enclosed areas with line of sight or good bounce for the IR signal, but falls down outdoors when bright sunlight hits sensors, and when the sensors are not in line of sight or just too far away.

Digging into alternatives, I first decided on RadioPopper PX triggers. The technology is simple and reliable, and should (but is not warranted to) work with off-brand CLS-capable flashes.  The capable PocketWizard FlexTT5 / AC3 combination was out of the running, because it is limited to brand-name (in my case Nikon) flash – driving the system price up substantially.

A modest three-flash RadioPopper PX setup would cost about $1000. Ouch. Some people can afford it, but of those, who would want to?

DIY seemed feasible – this is largely about converting IR to Radio and back again, with no need to reverse-engineer coded signals from multi-pin hotshoes.  Google found people doing “DIY RadioPoppers”, but with reliability issues, short range, and a fair bit of soldering and component sourcing.

What to do? Try the Chinese, of course. Enter AK-TTL. The literature sounds good: put a transmitter near a CLS source (built-in Commander flash, SU-800, on-camera Master flash) and receivers at the off-cameras flashes, then manage as usual only with longer range and no line-of-sight limits – rather like the RadioPoppers but at a much lower price point.

AK-TTL RX module with SB-700


Since lots of things sound good until we try them, let’s have a look at what I tried and how everything turned out. My concerns were, roughly in order:

  • compatibility. Would they work with a variety of components both Nikon and other? With all of the options on my SU-800?
  • reliability. Would they produce a flash nearly 100% of the time?
  • distance / obstacles. What distances, with direct line of sight or intervening obstacles, would still have relatively usable reliability?  Would it work well at short distance (mere inches / feet from the transmitter)?
  • “gotchas”.  What hidden limits were going to be a problem to one degree or the next?
  • overall utility.  How long would the batteries last?  Was the physical construction up to the job?  Were the flash interfaces adequate?
  • as a bonus, the AK-TTL works as a manual trigger – is it any good?
  • support.  This is last because really, what can we expect for such a small price?

If you like quick information, skip to the Summary at the bottom.

Caveats / Assumptions

  • Nothing lasts forever. My testing time has been limited – extended use in real-world conditions will build confidence.
  • I could not test, because my camera won’t do it:
    • x-sync speed past 1/200s, either CLS or Manual (AK-TTL is claimed to go up to 1/250s). 2013-04-10: I have now tested up to 1/250 on a D7000, works fine.
    • the claimed HSS capability.
    • built-in Commander flash compatibility.
    • regarding these untested capabilities, they should work: the AK-TTL is not interpreting various coded commands, just transmitting the already-coded commands via radio frequency.  Having said that, everything needs to be tested before counting on a given function.
  • 2012-09-06 note: Mic Ty has run some tests on HSS and built-in Commander flash – both worked well for him.

What Came in The Box

AK-TTL by Aokatec – Everything Delivered

On delivery, the AK-TTL system came with these items:

  • the transmitter  / receiver (TX / RX) pair.
  • cables to connect to a flashes via IR (an emitter) and manually (PC and 3.5mm).
  • two heavy, yellow bands to hold the IR emitter on the flash.
  • two lanyards ( I don’t know why you would need one on the TX, so one is a spare).
  • a handy IR-passing (visible-light blocking) filter + mount to use with Commander-capable cameras, replicating the SG-3IR filter function with the addition of an AK-TTL TX mount.
  • several pieces of good-quality Velcro (aka “hook and loop fastener”).
  • two thin, self-adhesive rubber cutouts to help place and hold the IR emitter.

AK-TTL Rubber Cutouts (left of the Emitter)
The die-cutting is hard to see, but there.

The packaging was sparse but sturdy.

AK-TTL Packaging

Testing and Notes


I have access to a Nikon D5100 (and now a D7000), an SU-800, and these flashes: Nissin Di866 II, Nikon SB-700, Oloong SP-660 II.  And of course an AK-TTL TX / RX module pair.

Test 1: Compatibility

Protocol: at ranges from a yard to about ten yards, try combinations of Master / Remote.

Result: On every aforementioned flash, using the SU-800 as a Master, the i-TTL and Manual SU-800 modes worked ( I did not try the Automatic mode, as I never use it). For each of the Master-capable flashes (Di866, SB-700), the Remote flashes worked on i-TTL and Manual.

Test 2: Distance / Reliability

Note: After doing the initial Distance and Obstacles tests with rechargeable NiMH batteries, I asked Aokatec support about optimizing distance. Aokatec support said “set the RX upright lettering facing the TX”, and keep the RX “more than 1.5 meter” above the ground. I used this guidance in the second test set as in “Note 2″.

Note 2: My initial tests were done with rechargeable AAs.  Thinking about that – rechargeables put out a nominal 1.2v and Alkalines are nominally 1.5v (both higher in practice) – I tried it again with off-brand Alkaline AAs – what a difference.  The line-of-site went from about (paced-off) 75 yards to a measured (laser rangefinder) 131 yards.  I did not re-test the Obstacles distance, but we can expect similar percentage increases in range.

Protocol (reflecting Note2 ): D7000 with built-in Commander, SB-700 on stand six feet up, IR sensor facing away from the camera, set to TTL via the built-in; AK-TTL TX / RX mounted as shown in the manual with RX facing the camera as suggested by tech support; Alkaline batteries; start at fifty paces; face the flash and take five shots; backup ten paces; repeat until firing is unreliable or the flash just stops working.  Done in an open field, and measured with a high-end laser range finder.

Result: all shots fired up to 131 yards! After 131, it became rapidly unreliable.  This was good, and exceeded the rated range  of 110 metres, or 120 yards. With rechargeables, I got only about 75 yards – so the lesson is to use cheap Alkalines if range is going to be an issue.

AK-TTL at about 75 yards
Bare Flash

AK-TTL (RX module at bottom of frame) Triggering SB-700, with Meking Mini Speedlight Softbox
(both diffusers installed, flash zoomed to 70mm)

AK-TTL Triggering SB-700 at about 75 Yards
This time with a Meking Mini Speedlight Softbox
(image cropped differently from the previous bare-flash image)

Test 3: Manual Trigger

Protocol: D5100, SU-800, SB-700 set to manual power via the SU-800; set the flash / AK-TTL RX combo six inches from the on-SU-800 AK-TTL TX unit (simulating product photography or bracket-mounted-flash).  Do ten shots.

Result: All shots fired.  During other manual use ( I don’t always drag out the SU-800 ), all shots fired at various ranges.

Protocol: equipment as above, ten yards from the RX, try 1/200s shutter speed (the AK-TTL is rated for 1/250s).

Result: perfect, no banding.  This is better than my RF-603s, which lose the bottom of the frame with the Di866 at 1/200s (the SB-700 works fine the the RF-603s).  I have since tested up to 1/250s with an SB-700 with perfect results.

Test 4: Obstacles

Obstacles bring in many uncontrollable variables: radio waves bounce off of conductive objects.  But we can run some simple tests and get a ballpark idea about how obstacles affect range.

Protocol: D5100, SU-800, Di866 set to manual power via the SU-800; rechargeable batteries; put the flash with a snap-on diffuser into my car (inside its garage), out of sight on the flooring in the back, and back away until the flash no longer fires (stride measurement as above).

Result: all shots fired up to 30 paces.

AK-TTL on the rear floor of a car, 30 paces, firing a Di866 through a snap-on diffuser.

Protocol: gear as above; rechargeable batteries;put the flash on the floor in the middle of a room on the second floor of a house, go outside and back away until the flash no longer fires.  The wall in question is standard North American residential construction with aluminum siding.  The floor – which is also an obstacle because of the second-floor location of the flash – is standard carpeted flooring.

Result: all shots fired up to 15 paces from the house.  The Aluminum siding would have been an issue.

AK-TTL firing on second floor of house, aluminum siding. Di866 with snap-on diffuser.

Protocol: gear as above; rechargeable batteries; flash positioned out of sight to the left of a double glass door, first floor.

Result: all shots fired up to 21 paces.  Better.

For the obstacle course: AK-TTL RX attached to Nissin Di866 Mark II


Overall Utility

Build Quality

AK-TTL RX module
Note the good finish.

Overall, quite solid.  The Manual/Off/Automatic switch on both TX and RX felt like it would keep working.  The channel selector switch turned easily with crisp detents and no free play.  The TX hotshoe (used for Manual triggering) fit nicely on my camera – no securing device, but the TX is light and will have nothing attached to it, and the fit was sound.  I never worried about it falling off, and it moved not at all during testing.

The Test button was crisp, and worked.

The fit and finish on the units was good: no mould lines, the white lettering was clear, and the two halves of the cases seemed firmly commingled.  The battery covers required firm pressure to remove and re-attach – they won’t come loose by themselves. The included lanyards are light-duty, but the units are lightweight and I expect no trouble.

Two small niggles:

  • First, the battery door locking tabs look fragile (they may not be, but it looks that way to me) – I will apply some tape when using during a shoot.  To put this in perspective, my RadioPopper battery doors were even more fragile-looking, and I did break the tabs on one of them.
  • Second, the battery compartment’s -/+ polarity indicators are moulded-in without any colour, making them hard to read.  Younger eyes would help, but in lieu of that I will apply a white paint marker – or just look at the battery door, where the metal plate is convex over the “-” and concave over the “+”.

AK-TTL Battery Cover
Note the locking tabs at right (sticking out) and lower left (under the housing).

Update to the battery door niggle: Aokatec, in response to suggestion, has started making slightly-thicker latches on the battery doors – they sent me a few, and the latches are indeed more robust in appearance and feel.  They measure .007″, or about 15%, more thick.

Closeup of the updated latch.

Closeup of the updated locking tab on the AK-TTL battery door.

One minuscule niggle: no manual was included.  Since the PDF manual is readily available online, and I prefer PDF manuals anyway, this may even be a benefit.

Given the price, I can’t see anyone complaining about visible quality.

Flash interfaces

We have either an IR emitter for Automatic mode, or a PC or 3.5mm connector for Manual mode. The IR emitter has a rubber face which acts both as a light seal and as a friction surface to stop the emitter from moving around once in place.

Further, the TX/RX package came with two thin, adhesive-backed cutouts that match the IR emitter’s outline. The PDF manual did not mention them, but Aokatec support confirmed that they are intended to both set a repeatable place for the emitter (on some flashes, the IR sensor location is not obvious) and hold it there with a rubber / rubber interface.  Someone with a lot of flashes would want more, but you get two with each RX so that may be enough (and they aren’t required, just helpful).

Aokatec support says using the cutouts “on the Nikon flash is not very necessary”, and I agree, but used one anyway to show it in place.

AK-TTL emitter locator / friction cutout on SB-700
In practice, the emitter stays in place without this – but this makes it faster to re-find the right spot for it.

Once the emitter is in place the large yellow rubber band holds it.  In practice, once I had it in place, it remained there – I looped part of the emitter cord back up under the band to act as a strain / jostle relief.  I prefer this band to yet-another-piece-of-velcro on my flashes, and to flash-specific brackets.

The PC cable fit nicely and worked perfectly on my Di866 and SP-660 (the SB-700 does not have a PC connector) and the 3.5mm jack, while I don’t have a flash that uses one, snapped crisply in and out of a sample female receptacle.

Because the IR Emitter uses a standard 3.5mm jack, it can be at any distance from the RX.  I have used it with a 30-foot stereo extension cable, which allows the flash to be deeply hidden and the RX unit to be discretely in, or close to, line of site.

Battery life

The manual claims 30 hours of continuous use.  After recharging, I put several hundred shots on the units in mixed Automatic and Manual mode, no problems.   I did not run the batteries out during testing – did not want to just hit the shutter until they died.  With off-brand Alkalines – a few pennies each in bulk from Home Depot – I will just put a fresh set in before an event, or any time I can’t get to the units to change batteries should they expire.


Aokatec responded promptly (less than twenty four hours) to my emailed questions.  I did not disclose that I was writing a review.


  • the transmitter / receiver pair was delivered to Canada, starting from eBay and including a weekend, in eight days.  This is unusually quick.
  • at close ranges on the SB-700 – under a yard – enough IR leaked to the sensor from the SU-800 (I assume through the front panel of the SB-700) that the flash would not fire (two differently-timed IR signals, one from the SU-800 and on from the AK-TTL RX IR Emitter, must have confused it).  So I covered most of the front panel, problem solved.  Similarly, I taped-off the area around the IR sensor on the Di866 and SP-660.  I will make black cardboard covers, held in place by the bands, for production use at close ranges – although at close ranges I would normally just use the SU-800 directly.
  • unlike some flash triggers, the AK-TTL does not act as a camera shutter release. So take the money you saved with these triggers and pick up a cheap set of Commlite Comtrig T320s, or, even better, a purpose-built Pixel TW-282.



As a CLS / i-TTL wireless radio frequency trigger, at about one-fifth the cost of the RadioPopper PX system, the AK-TTL system is, at least with my sample and testing regimen, a good thing.  I had complete reliability, usable range, and the build quality looks and feels good.  Combined with, say, the Oloong SP-660 II, we get a truly affordable off-camera flash with long-range, obstacle-accommodating CLS control.  Long-term reliability (including that of the Oloong flash) has yet to be determined but, at the price point, I say try it out.  As of now, I have used this setup at multiple events with total reliability.

As a manual trigger, the AK-TTL worked fine with my sample and testing regimen, at a reasonable price point.

Here is the true performance gain: no more taking umbrella-softboxes apart, jogging over to and climbing up and down ladders (or lowering and raising light stands), shielding the IR sensor from direct sunlight and keeping the subject engaged while all this is happening.  At this price point, all of my current and future flashes can be remotely adjusted.  Even a hard-core manual “strobist” will see the benefits.

AK-TTL TX on top of SU-800

AK-TTL TX on top of SU-800

Next Steps

Wouldn’t it be interesting to mount my SU-800 on a i-TTL-pass-through manual trigger – then control the power of the manual flashes with “itsskin”-style triggers (also seen / discussed here) to give many planes of light and still have i-TTL available for unpredictable subjects?

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