I stand corrected. But, if I remember correctly and I don't need to get corrected again, before it was so that when you half-pressed, the image stabilised. With a long lens It was easier to precisely frame the shot while you were half-pressing before you took the shot.
Now in AF-S, IS set to "Shooting Only", half-pressing does not stabilise, but @Greybeard, sir you are right, the actual image is stabilised as the shot is taken.
In AF-C, the behavior is as I remember it, with IS set to "Shooting Only" half-pressing stabilises the image. You can clearly see this in the viewfinder. With miniscule movements of the camera, the image moves with the camera while half-pressing, but the camera moves versus the image while not.
I don't know if this was changed with the most recent FW or earlier. Heck, I am not even sure if I remember this from Fujifilm X-T10, X-T2 or from my previous brand. I haven't been using long lenses for quite some time. Am I right ? Or was this only in AF-C from the start ? Thank you.