Cactus Imaging have just announced release of new firmware for their Cactus V6II radio transceivers which will allow Micro Four Thirds users the ability to use Canon, Nikon, Fuji, Sigma or Olympus flashes (or a Cactus RF60X flash) in remote TTL mode with Super FP/High Speed Sync capability as well as remote manual flash power output control or zoom control.
This means you just need to buy two Cactus V6II radio transceivers, install the Olympus X-TTL firmware on EACH radio transceiver, attach one to the hotshoe of your Micro Four Thirds camera, and the other to the remote flash hotshoe and hopefully most of it will self-configure by detecting which brand flash you are using.
No more annoying optical signalling between your camera and flash units!
If you are like me and have a couple of Canon 580EXII flashes lying around, these can now be used with your Olympus OM-D E-M1 Mark II, either mounted on camera (on top of a transceiver) or remotely on a second transceiver and used with full TTL or manual control up to 100m away! I have tested it in my lounge room and it seems to function well.
Of course, you can buy a few transceivers to operate a number of remote flashes and control them all from the camera – very nice indeed!
The bad news is that for photographers with more than one brand camera, they will need to have a different firmware in the transceiver for each camera brand and the remote flash transceiver needs to have the same firmware as the camera (NOT the flash) – the exception here is if you have a Sony camera, you need the special dedicated Cactus V6IIS Sony transceiver for the camera, and a Cactus V6II for a Canon, Nikon or Olympus flash but in this case the flash transceiver must be loaded with Fuji or Sigma firmware for TTL compatibility with these flashes. Fortunately, you can install different firmware as your needs change – you are not stuck with one camera brand firmware for a Cactus V6II, but it seems that the memory inside the Cactus V6II is not sufficient to allow Cactus to create a multi-brand camera TTL firmware to avoid this issue – guess we may have to wait for the Cactus V6III for that to be possible. However, given that the Fuji and Sigma firmware works with the Sony firmware and that Cactus have indicated they had to create a substantial change to the firmware design with the recently released Pentax firmware which presumably the carried over to the Olympus firmware, once the Sony, Fuji and Sigma firmware are updated to this new change, they might be able to be made compatible with the Pentax and Olympus firmware so that a Sony with a Cactus V6IIS might be able to control a Cactus V6II with Olympus firmware attached to a Canon flash. Confusing yes, but in the end it should just work and be more simple than the current incompatibility.