Any flash used with a Fuji X-camera, other than a dedicated Fuji flash, can only be used in manual or automatic mode.
As a side benefit, the two Yongnuo units can be set up as a wireless remote control of the camera. Simply attach a cord from the side of the unit to the cable release input on the Fuji X-camera.
|Mount the RF-603 on the X-T1 hot shoe and turn it on to TX, for transmit.|
|Mount the second unit on the flash and turn it on to TRX, for receive. You can test the connection from either unit by pressing the test button on top.of it.|
|When shooting with a flash on a Fuji X-camera, the frame rate needs to be set to "S" for Single, otherwise the camera will not shoot.|
|Here the Nikon flash is set to ON and Manual mode. Note that the flash focal length is set to FX zoom. To be totally accurate this should be changed to DX when used with the Fuji X APS sensor.|
|Here the Nikon flash is set up as a Master unit so that it can control another flash, either another Nikon flash or a second Yongnuo flash. In this case, both units are on Channel 1. We could set up more units on the same or different channels.|
Below is a short video I did to demo the setup on a Fuji X-T1, X100T, and X-Pro1.
Any of these units will work with a Fuji X-camera, but only designated units can also be controlled by a Nikon or Canon camera so be careful about which model you are ordering. It gets confusing and the prices vary slightly, but here is a list with a link to their availability on Amazon. You can also find them on eBay, but by ordering on Amazon you get the instant gratification of receiving them right away.
For pro Nikon cameras and the X-T1:
Yongnuo RF-603NII-N1 Wireless Flash Trigger Kit for Nikon D700, D750, D800, D810, D1 D2 D3 D4, D4s
For amateur Nikon cameras and D610 series, and the X-T1:
Yongnuo RF-603NII-N3 Wireless Flash Trigger Kit for Nikon Nikon D90 / D7000 / D7100 / D5000-5500/ D3100 - D3300 / D600 / D610
For pro Canon cameras and a Fuji X-camera:
Yongnuo Upgrade RF-603 II C3 2.4GHz Wireless Flash Trigger/Wireless Shutter Release Transceiver for Canon 1D/1DS, EOS 5D Mark II/5D/7D/50D/40D/30D/20D/10D Series (RF603II C3)
For Canon cameras and Fuji X-camera:
For amateur Canon cameras and a Fuji X-camera:
Yongnuo Upgrade RF-603 II C1 Flash Trigger/Wireless Shutter Release Transceiver Kit for Canon Rebel 300D/350D/400D/450D/500D/550D/1000D Series