I have a Nikon D3100 camera, and I'd like a flash setup that I can use off-camera, that takes advantage of the camera's iTTL feature and that doesn't depend on its popup flash. I'm considering using a Yongnuo YN-622N controller in the hotshoe and a Yongnuo YN-568EX flash unit off-camera in TTL mode.
Does anyone know if this will work, or of any alternative units that would give me what I want?
You'd probably be better off using a YN-622N-TX dedicated transmitter on the camera. It has a small LCD screen so you can see what your settings are all at once. The YN-622N only has a few LEDs to indicate a lot of different things, and it can be a bit more of a PITA to use than a YN-622N transceiver unit.
If you still want TTL/FP (HSS) and remote power commanding over radio, however, you also should understand that the YN-568EX does NOT have a built-in radio receiver. You will also have to get a YN-622N and attach it to the foot of the flash, as well as having the YN-622N-TX (or another YN-622N) on the camera's hotshoe.
The only flash Yongnuo makes that has a built-in YN-622 receiver is the YN-685, and at this moment, it only comes in Canon flavor; and has no optical slave modes at all. Theoretically, it might work with a YN-622N-TX, but the only folks who've bought one so far and are reporting about it on the internet are Canon shooters.
There are a number of alternatives you can go for, aside from the Yongnuo flash/trigger combinations, but Yongnuo is probably the cheapest one with a good reputation. You could also look at Phottix's Odin system and their Mitros/Mitros+ flashes (more expensive, but easier to expand and better reliability/build reputation). And, of course, there are the TTL PocketWizards and RadioPoppers if you need pro reliability Sekonic lightmeter integration.
