New wireless TTL trigger from Aokatec
The relatively unknown Chinese company Aokatec has just introduced a wireless flash control radio relay named AK-TTL that looks like a low-cost alternative to the RadioPopper PX system.
While a RadioPopper PX TX/RX pair will cost you around USD 378, (search eBay for the Aokatec AK-TTL), a starter kit with a Aokatec AK-TTL TX and RX costs less than a third of that, around USD 109.
The AK-TTL comes with a hot-foot and sync cord socket that allows it to be used as a simple manual radio trigger with studio flashes and other non-dedicated units. On the side of the unit there is a switch with positions “Off”, “M” and “Auto”. You use the “M” (for “Manual” position for manual operation. However, it is the “Auto” mode that makes the unit, attractive, so this is the mode I shall discuss.
Like the RadioPopper PX, the Aokatec AK-TTL in “Auto” mode is a hybrid trigger that takes the signal produced by an on-camera commander and converts it into radio signals. This radio signal is then converted back into light signals at the receiver end. The hybrid approach means that the you must use a dedicated commander unit to generate the control signals. The AK-TTL is just a relay, using radio to extend the distance the signal from commander to remote is able to travel.
As commander, you can use:
- The pop-up flash on a compatible camera (e.g. the Canon EOS D7, Nikon D700, Pentax K-5 or Sony A77).
- A wireless transmitter placed in the camera's hot-shoe (e.g. the Nikon SU-800 or Canon ST-E2).
- A master flash in the camera's hot-shoe (e.g. Canon 580EXII, Nikon SB-910, Pentax AF540FGZ, or Sony HVL-F58AM).
In three all cases, you set the mode, optical channel and group, power, etc. on the commander, on not the AK-TTL.
The you buy a kit with one AK-TTL TX and one RX, you receive:
- AK-TTL TX.
- AK-TTL RX.
- ASC-1 Sync Cable 3.5 mm to IR-sender (for auto mode and dedicated flash).
- ASC-2 Sync Cable 3.5 mm to pc-plug (for manual mode and small flash)
- ASC-3 Sync Cable 3.5 mm to 3.5 mm (for manual mode and studio flash).
- IR-pass panel with mounting bracket.
The standard kit does not include a printed manual, but you can download the manual (pdf-format) from Aokatec's web-site.
The Aokatec AK-TTL does not in any way interpret the signal it intercepts. This means that that same TX and RX units should work with the dedicated flash system of any manufacturer, as long as it is able to intercept the commander unit's control signal. On the Aokatec web-site, the following flash systems are listed as compatible:
- Canon optical wireless E-TTL.
- Nikon i-TTL AWL/CLS (Advanced Wireless Lighting/Creative Lighting System).
- Pentax Wireless P-TTL.
- Sony Wireless P-TTL.
Note that the AK-TTL is not compatible with Canon's own radio-based wireless E-TTL flash system or the Canon ST-E3-RT wireless transmitter.
The Canon, Nikon and Pentax TX and all RX have a standard ISO foot. The Sony TX has a Sony/Minolta foot.
Here is a summary of its main features, according to Aokatec:
- Lets the photographer control remote flash units (TTL and manual) from camera position by means of radio relay function. Wireless flash is set up using camera manufacturer's system. I.e. no need to learn new system.
- Can trigger multiple flashes simultaneously with multiple RX units.
- Supports HSS/FP up to 1/8000 second.
- Range up to 110 meters (360 feet). [See below.]
- The TX and RX each uses two standard AAA batteries.
- Uses 2.4 GHz band, 16 transmission channels are available.
Note: During field testing Aaron Burns did not get reliable operation beyond 75 meters (245 feet).
The AK-TTL TX needs to be placed very close to the commander in order to intercept the signal. The PDF-manual has a diagram showing where to place the TX with different types of commanders. There is also photographs of suggested placements at Aokatec web-site. Aokatec supplies a shoe mounted IR-pass panel to be attached to the camera's accessory shoe that is similar to the Nikon SG-3IR, but designed to let you place the AK-TTL TX om a mounting bracket just above the raised pop-up flash. The panel's cold-foot is designed to not trip the micro-sensor used by Canon to detect the presence of an external shoe-mounted flash. The Sony TX panel has a Sony/Minolta foot.
The AK-TTL RX comes with an IR-sender that must be placed over the optical IR “window” on the remote flash, attached by means of velcro or an elastic band.
The IR-sender fits snugly over the small round “windows” used by Nikon for the IR-sensor on Nikon Speedlights, but other flashes (e.g. the YongNuo YN-560EX and Nissin Di866) have large opaque panels in front of their IR-sensor, and you need to experiment to locate the sensor. When you've found it, you may need to place cutout markers on the panel to be able to repeat correct placement of the IR-sender. You need to use elastic bands or velcro to secure the IR-sender in place.
As long as you stay in range, and make sure the IR-sender is well aligned with the IR-receiver on the remote flash, the system works well and is reliable.
However, users need to be aware of a phenomenon called “interference”. If a remote flash receives an IR signal from both the AK-TTL IR-sender and a line-of-sight optical signal from the commander, the two signals interfere with each other and the remote flash does not fire. This is more likely to happen at close range, when the line-of sight optical signal may be quite powerful. Making sure the sensor on the IR-remotes face away from the commander (so there is no line-of-sight) usually makes the problem go way.