Ranger_9 2:08am, 13 September 2012
We've had a couple of threads (here and here) about the Aokatec AK-TTL triggers that claim to provide radio-synced wireless TTL with a variety of flash systems.

Until now the discussion has been all about using them with Nikon and Canon, which isn't too exciting since both those systems already have alternatives such as Pocketwizard's Control TL system and the Phottix Odin.

My idea was more of a gamble: I bought a set of Aokatecs hoping that I could use them with the wireless TTL system of my Olympus E-M 5 -- a system Aokatec doesn't even officially support. [Updated 9-15-2012: Aokatec's website now lists Olympus as compatible.]

Guess what: it works!

This is kind of a big deal because until now, there has been NO way to use Olympus' excellent wireless TTL setup with a radio system. You've been limited to the optical triggering built into Olympus camera bodies and flash units. Like other manufacturers' optical wireless systems, this works great at short distances and under subdued light -- but gets janky at longer ranges, in bright sunlight, or if there isn't a clear line of sight between the control flash and the receiver flash.

As noted in the other posts, Aokatec gets around these limitations by using a radio-frequency "repeater" system. The transmitter reads the master flash unit's optical control pulses (by sensing the electromagnetic burst from the flashtube) and translates them into equivalent radio pulses. The receiver captures the radio pulses and translates them back into optical pulses via a little plug-in infrared emitter, which you strap onto your receiver flash so it sits over the flash's optical signal sensor. This repeater concept was pioneered by RadioPopper and is well proved by now.

The trickiest thing about getting the Aokatec units to work with my Olympus gear was finding out exactly where to put that little IR emitter. The receptor on the front of my Olympus FL-36R flash unit is covered by a large piece of dark red plastic that also houses the AF light and the autoflash/slave eye; I couldn't see through it well enough to spot the control sensor. So I carefully pried off the red plastic piece:


There it was, down low on the left-hand side. With the plastic cover back on, I was able to line up the Aokatec emitter correctly by aligning it with the top and left edges of the word OLYMPUS printed on the cover, and secured it in place with one of the supplied elastic bands:


The Aokatec transmitter comes with a clever little bracket for use with pop-up flashes, and a standard foot for shoe mounting. But I couldn't use either of those: the little folding flash unit that came with my Olympus E-M 5 occupies the camera's flash shoe. (Incidentally, although this flash is tiny, it works as a full-fledged wireless TTL controller via the E-M 5's flash control menu.)

The best I could do was attach the transmitter to the top of the flash with another elastic band. Fortunately, placement of the transmitter turned out not to be critical: it can sense the flash firing pretty much no matter how it's mounted.


(A slight problem: Pushing down the flash head shuts it off, and the extra weight of the Aokatec transmitter made it a bit prone to push down accidentally. I slid the elastic band all the way back to the hinge to make it a bit less likely to close on its own.)

Sorry I don't have very inspiring subject matter for my test shots, but I wanted to try this out right away! To give the TTL system a workout, I mounted the FL-36R in this Interfit S-mount bracket, which let me use a standard reflector and a 20-degree grid. The bracket also has an extra mounting shoe that's handy for holding the Aokatec receiver:


I set up deliberately harsh lighting for this test shot. The Olympus flash system gives full control of three channels from the camera menu (it works almost exactly like a Nikon CLS setup) so I dialed in -0.7 stops of flash compensation to get the look I wanted:


The Aokatecs also kept pace just fine with Olympus' "FP" high speed sync mode. Here I shot with a mixture of fluorescent ambient light and flash, using a shutter speed of 1/80:


Then, with no other changes, I turned the shutter speed up to 1/4000. That killed the fluorescent ambient (as you can see by comparing the shadows with the previous photo's) but the TTL-metered flash exposure was still fine:


So aside from the fiddly transmitter mounting (I'll need to think some more about that) the Aokatec system seems like a win: no-sweat, no-bother radio TTL for Olympus! I'm stoked...
MadMick PRO 3 years ago
That's awesome.

This system has some great potential for sure. Maybe you can mod a bracket to screw into the tripod mount of the camera and attach the IR deflector with the Tx in it to your uber bracket? would be a bit finicky but keep the weight off the flash? Dunno, Elv might be able to make/design u bracket :)
Ranger_9 Posted 3 years ago. Edited by Ranger_9 (member) 3 years ago

-- I did a bit more work on mounting the transmitter to the little accessory flash that comes with the E-M 5 (the FL-LM2, for model-number sticklers.) You won't want to do this unless you're okay with a semi-permanent "mod," but here goes...

The Aokatec kit comes with a nifty bracket for holding the transmitter over a pop-up flash; this consists of an arm, a blocker panel, and a separate plastic shoe that clips onto the arm via four little hooks. I don't have a camera that can use the bracket -- so I pilfered the shoe, trimmed off the mounting hooks to get a flat surface, and glued it onto the flat back of the flash unit, like so:


The shoe holds the transmitter in the right place and even (from the front) looks reasonably official, like this:


Note that since the transmitter is attached to the back of the flash's mounting base, there's no weight on the folding part and no extra risk of folding down the flash head accidentally. The flash can still be used normally without the transmitter attached, if you don't mind the extra part sticking up in back. Durability? Well, I wouldn't use it at a football game, riot, wedding, or other form of civil insurrection, but for careful studio use it seems reasonably sturdy. Besides, the worst that could happen is that it would come off and I'd have to glue it on again...

-- Meanwhile, I also made a small improvement to the little IR emitter that connects to the receiver and goes over the sensor eye of your flash. It didn't want to sit quite squarely against the slanted bottom edge of my FL-36R flash, so I cut a little wedge of rubber and glued it onto the bottom edge of the emitter, like this:


The rubber fills the gap and makes mounting the emitter more solid.
Ranger_9 Posted 3 years ago. Edited by Ranger_9 (member) 3 years ago
How about Range?

People in the other threads have reported varying experience with the range of the Aokatec units; the instructions claim 110 meters, but some people have reported less than a third of that. I did a bit of experimenting to see how it gets along with the Olympus:

Again, apologies in advance for the non-exciting test photos! I set up the flash and receiver on a light stand in my garage and pointed it at the back of my car, like so:


No problem firing from my upstairs apartment:


To get a more quantified idea of range, I went outside and paced off distances (having grown up playing pickup football games, I can pace yards fairly accurately.) At 35 yards away, we're fine; you can see the flash in the open garage door (all pictures made with a 20mm lens, which is the equivalent of 40mm on a 35mm camera):


Now we're 50 yards away and still firing:


Now I'm across the street and about 60 yards away, and you can still see the flash in the garage door:


This is about 65 yards away standing in a private driveway. Considering what the police probably would do to a weird guy with a camera standing in a stranger's driveway at night, this is as far away as I dared test -- but you can still see the flash in the garage doorway:


Now, all you Canon and Nikon people who own Pocketwizard ControlTL or Phottix Odin setups might say, "What's the big deal? I've been able to do that since last year!" But remember, those triggers are NOT available for, or compatible with, the Olympus wireless flash system.

This DOES work with Olympus, it seems reliable, and it's not ludicrously expensive...
Ranger_9 3 years ago
Another update: I see that Aokatec has updated its website so it now lists Olympus as one of the compatible flash brands. I guess that makes it official! (Maybe they'll publish photos showing the locations of the control sensors on various Olympus flash models, so people don't have to pry the flash units apart to find out where the IR emitter should be mounted...)
elv0000 3 years ago
Thanks for this, thats plenty of range.

Mick has another set on they way so we should find out if its just a faulty set, or possibly the pick up is just not as sensitive with Canon.
Ranger_9 3 years ago
I wonder if the known issue of RF noise emitted from some older Canon flash units might be limiting range, as was the case with Pocketwizard's initial ControlTL release...?
dallascowboys2011 3 years ago
Too bad all the images have been removed :(.
shooter1229 PRO 3 years ago
I am using a Nikon Flex TT5 system with my OMD EM5 and Panasonic GH3. By using the Sekonic L-478DR meter I can control and meter Nikon Speedlites as well as Einsteins and Alien Bees. Just have to set up Flex's as directed on Sekonic site. Works great.
Ranger_9 3 years ago

Yeah, I thought everybody was done with this thread and I was getting close to my 200-image limit, so I took them off. I'll see if I can put them back if people still need them.
Ranger_9 3 years ago

Right, you can manually set the power of your remote flashes from the meter, which is very cool. What's good about the Aokatecs is that they let you use either TTL auto or manual power setting via the RC menu on your camera; you can't do TTL with the Flex/Sekonic setup. Different problems, different solutions, different advantages. I'm glad we finally have several options!
elv0000 3 years ago
You can 't do HSS either with TT5 on a different camera.

This was a good thread, that trick is to start a new account :-) (it is a hassle though)
Nionyn_ PRO 3 years ago
...I was getting close to my 200-image limit, so I took them off.

The 200 image limit only applies to free accounts.
Yours is 'pro' so does not have that restriction - unless you have taken advantage of Flickr's temporary pro account Christmas freebie, of course, in which case it will revert to the free account with 200 limit in time.

As Elv suggests, if your account is in fact a free one you could open a second account for stuff like this (to the best of my knowledge Flickr appear not to object to people doing this). Then you could use your present account as you do now for posting in discussions etc., and the other account for technical gear pics. You could even use the same avatar and call the other account something like "Ranger_9 - gear pics". Or something. :-)
AlexFoto2008 2 years ago
Since there isn't anymore the limit of 200 visible images perhaps, you could put the images again, if you remember where you stored them during all this time.
Bob Muenchen 2 years ago

A simple solution to keep the tiny OMD flash from tipping over from the weight of the transmitter box is to cut some 1/2" black velcro cable ties into 1.25" strips and stack them up. Six layers of these will fit perfectly under the flash head, keeping it in the "fire" position. It's easy to insert and remove at that size. This is the type of thing I used:
Chef Luis Jiménez PRO 2 years ago
Awesome post, and it responds perfectly to my dilemma on flash triggers for the OMD-E-M1, I found this place thanks to this blog betterfamilyphotos.blogspot.mx/2013/01/yongnuo-rf-603-oly... wich has a different approach to answer the same question. Cool to know that we olympus users have choices.
Too bad that there are no more images in this post, hopefully the 200 pictures issue gets solved soon.
Best regards.
Nionyn_ PRO 2 years ago
The 200 picture limit for free accounts is no longer relevant. Since Flickr/Yahoo changed their business model some months back everyone gets a free TB of photo storage, irrespective of the type of account they have and whether they pay for it or not. Also, all photos uploaded are now visible.

I have no idea whether Ranger_9 is likely to upload the photos again, however (or if he even still has them). This is now quite an old thread, after all.
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