Can I control off-camera flash power by radio on Olympus OM-D, without using optical RC?

Question

I use an Olympus OM-D E-M5 and would like to adjust off-camera flash power from the camera position, rather than walking to each flash. Olympus’s optical RC system can do this, but on the E-M5 it requires the FL-LM2 clip-on flash as the controller.

Is there a radio-based system for Olympus/Micro Four Thirds that allows remote flash power control from the transmitter or camera setup? TTL would be nice but isn’t essential; manual power control is enough. If not, is Olympus optical RC still the main option?

user27440 · Accepted Answer

As of 2018, aside from the built-in RC "smart" optical system made by Olympus and Panasonic, there are a few radio triggering systems that now support TTL and HSS with MFT (micro four-thirds), as well as remote power control. There are also manual-only systems with radio triggers built-in that support remote power control from the MFT hotshoe.

Full TTL/HSS systems

A number of systems now allow for full TTL/HSS communication (including remote power control) over radio:

Godox 2.4 GHz X system (aka Flashpoint R2)
Cactus V6II's X-TTL system
Nissin Air
Profoto Air TTL
Aokatec AK-TTL

All of these systems, except the oldest (the Aokatec) also offer some form of system-switching so that the lights can be used across different brands of cameras with the appropriate transmitter unit on the hotshoe. In the case of Nissin, however, the 10s transmitter that allows this, has not yet been released for MFT. And in all these systems, except for the Aokatec and Cactus V6II systems, it relies on controlling same-brand-as-the-trigger lights via their built-in radio receivers or transceivers.

Godox is probably the lowest cost system with the most expansion capability and options with lights.

Manual-only systems

In addition to the TTL/HSS systems, you can use any manual-only system where the flash has a built-in radio receiver that allows for power control, even though there's no power control capability on the foot. Some of the more popular systems are:

Yongnuo's "560" system
Lumopro's LP180R with an Odin II transmitter
FlashQ's Q20 and transmitter

The Yongnuo YN-560-TX can manually control the power level, zoom, and group on/off on the Yongnuo YN-560 III / YN-560 IV / YN-660 / YN-720 manual flashes. And all but the YN-560 III can also be used as a radio master in the system.

The Lumopro LP180R has a built-in Odin receiver that can be triggered by either an Odin II or a Stratto II, but only the Odin II can control its power remotely.

TTL/HSS Triggers for other systems

In addition, most other-system full-TTL triggering systems (e.g., Canon RT, Yongnuo YN-622, and PocketWizard TTL) can be used on the MFT hotshoe with remote power control (although, obviously, no TTL or HSS).