Fuji is, at this point, the last major manufacturer to not have TTL, high-speed sync, and wireless control support from most major lighting manufacturers. Profoto and Elinchrom have now made wireless remotes specific to Canon, Nikon, Sony, and Olympus. Fuji, even with their new medium-format monster, the GFX 50s, has yet to get such love from the lighting community. While I can imagine that something is in the pipeline from these manufacturers for Fuji, nothing is certain and many of us need something to work with right now. Enter the Nissin Air system.
At first you may think, "Nissin, really?" Yes, really. They have a very affordable kit at $299 that gives you a speedlight and a wireless trigger that allows you to have wireless power and zoom control, as well as TTL and high-speed sync with Fuji cameras. That's awesome and everything, but that means I have to buy all new flashes from Nissin if I want those features for my Fuji, right? Wrong. Nissin also manufactures receivers that solve (most) problems that Fuji shooters have. For $69 you can get a receiver for any of the flash manufacturers and sync it to your Fuji remote. That means that Nikon flashes, or any flash that is Nikon compatible, can be attached to the Nissin receiver for Nikon and fired and controlled from the Nissin transmitter for Fuji.
There are some caveats, such as not being able to use high-speed sync with non Fuji flashes connected to the system. But if you get the Di700 and receiver combo for that $299, that gives you your high-speed sync. The extra Nikon flashes that can be added into the system for very little cost give you the option to have a multiple light setup. If you absolutely have to have high-speed sync with every flash, extra Di700 flashes are only $259, making this system less expensive than any other full featured speedlight system available regardless of which camera you shoot with. For those of you that are GFX owners, you may like to know that the Nissin system functions with it as well as the X-Series cameras.
A lot of photographers these days are switching from Nikon or Canon systems to Fuji, and for good reason. But switching can cost a lot of money. For anyone working with flash regularly, the cost is even higher. Canon shooters can feel it the worst if they've invested into the RT wireless system. What the Nissin Air system allows, however, is for you to use any existing flash with the new Nissin transmitter on your Fuji and still have wireless control. If you own a few SB-800, SB-900/910, or 600EX-RT flashes and don't want to replace them once you make the jump, get the Nissin Air and a few receivers. And even if you're already a Fuji shooter and just want to get into flash, I highly recommend this system for its ease of use and versatility.