The article states:
"The most important thing you need to know about setting up back button focus: you must turn on the continuous AF mode (AF-C) on your dSLR for it to work on Nikon models."
, which seems a bit inaccurate. I haven't played with every single setting, but have used back button and seldom use AF-C.
It's only accurate in that for it to work the way in which they describe in this paragraph...
"Back button focus gives you the best of both focusing worlds: single and continuous AF. Keep pressing the back button to use continuous AF if the subject is moving back and forth in the frame, otherwise simply press the back button once to lock the focus. Then, you can take the photo using the shutter button and recompose to your hearts content without needing to keep finding focus."
...you need to do it that way.
Or, and this is the point I was going to post before realizing I can tack onto this post, you can change the Focus Priority in AF-S to
Release. Otherwise, as I talked about in my post about the D750's focusing, releasing the back button and recomposing will
not work on
some Nikons if you are in AF-S mode and the focus point winds up over an out of focus object.