Most of you heard of speedlight (flash) TTL triggers from PocketWizzard, Phottix and Pixel King. But I'm pretty sure that the majority of you didn't know about Aokatec's TTL triggers. Aokatec, like many other similar companies, is based in China. Honestly, I didn't know about Aokatec myself until I received their first TTL flash trigger for testing, a set of AK-TTL for Nikon. If you have been considering a TTL trigger from Aokatec (they have AK-TTL for Nikon, Canon, Pentax and Sony at the moment), then you might want to carefully read this short review because AK-TTL is not a typical TTL speedlight trigger and differs considerably from the TTL flash triggers currently available on the market.
How does the AK-TTL work with the transmitter?
The short answer is: unusually. The long answer is a bit more complex. I think the most important information for the potential buyers is that AK-TTL is very unconventional and I haven't seen a similar system on the market yet.
At first, I found the AK-TTL's way of triggering flash quite complicated, because the transmitter unit is not mounted in the camera's hot-shoe. Yes, you read it well and here is the complicated part. The transmitter doesn't obtain the TTL or triggering information from the camera's hot-shoe but from the built-in (little) flash. Therefore, you have to set up the camera's flash as a TTL off-camera trigger and pop it up. Then you place the AK-TTL's transmitter on a hot-shoe bracket.
I know that I still haven't answered the question how does it work. The Aokatec representative had to help me in solving the mystery and I was told that "when pop-up flash fires, there's an invisible electric wave around the (pop-up) flash. There's a special sensor inside AK-TTL TX (transmitter) that gathers information from electric wave. Then the TX processes the electric wave information into control signal data, and sends it to the RX (receiver)."
The problem I've found with the hot-shoe bracket (see picture) is that if you put it on the camera first before popping the flash up, the flash hits the bracket quite hard. I don't know if it might cause the built-in flash's plastic frame to break, but it's definitely something I would like to avoid from happening.
The Receiver - the missing hot-shoe
The AK-TTL's receiver (RX) doesn't have a hot-shoe for a an off-camera flash and I have to say that it's something I can hardly accept nowadays. So if you want to use the TTL capabilities of your camera and the off-camera flash in high-speed sync, things get a bit more complicated.
So to use the TTL, you need to take one of the cables that come in a box with AK-TTL - a cable with an IR sensor. You have to put this IR sensor (let's call it an IR transmitter) exactly where your off-camera's flash has it's IR receiver. To help you do that, Aokatec included a nice thick yellow rubber band that will hold the IR transmitter tight to your flash.
You have to be quite precise to match the IR transmitter to the flash's IR receiver, otherwise it won't work. Of course this adds few more steps to your workflow as well as extra cabling that you have to be careful about. For me, it's not a problem when photographing in a studio. However, I found it rather problematic when shooting on location, especially for clients, where everything has to be done quickly.
I found the AK-TTL for Nikon to be quite reliable. The only problem I had was that there was quite a lot of interference (probably from other household devices, like WiFi) where the RX (receiver) was triggering flash, even though the camera with a transmitter (TX) were lying on my desk untouched. Changing the radio channels solved this problem.
The AK-TTL proved to be reliable outdoor. Unfortunately, I didn't have a chance to test the real maximum distance between the TX and RX (FYI: Aokatec claims that the maximum transmission distance is 110m/360ft.)
Unfortunately, the AK-TTLs' boxes have to be improved and you have to be really careful when buying the units: there are no marks or indications whatsoever. You don't know from looking at the box whether it contains receivers and/or transmitters and for what camera manufacturer (Nikon, Canon, Sony, etc.). This is quite unusual so pay extra attention if you plan to get AK-TTL.
No manual so count on yourself
I received 2 boxes of AK-TTL and unfortunately there was no manual inside. I don't think it's much of a problem because you can get it online from the manufacturer's website. If you don't print it, you will save some extra trees :) Maybe Aokatec did that on purpose.
When publishing this review, you can get a set of AK-TTL (1 receiver and 1 transmitter) for Nikon, Canon, Pentax, Olympus and Sony for $109 (+ shipping and import taxes) directly from the Aokatec's online store.
I'll keep the final comments on AK-TTL short.
Pros: - relatively small and light units; - both the receiver and the transmitter use standard 2xAAA batteries; - quite reliable (I would give it 8/10).
Cons: - requires to use extra bracket for the transmitter that adds extra workflow and takes time to setup; - the IR cable with IR transmitter (attached to the receiver) has to be attached precisely on the speedlight's IR receiver, which often is hard to find on the speedlight - it adds extra cables and work, which I found problematic when working outdoor with a photo crew when things need to be quickly setup and ready; - no hotshoe on the receiver; - the price - looking at the pros, the cons and other alternatives on the market, the price could be a bit lower for AK-TTL.