Taco, take a look at your PVS 14, binos or some other quality optic with an adjustable ocular and note the adjustment that works for you, then compare it to the adjustment on the REAP-IR. It should be the same. Some of the ocular focus rings on PVS 14s, Patrols, MK IIs, IIIs and EEAP-IR are very stiff. (Same ocular.)
Also, though I suspect you know about it, there is digital focus adjustment in the REAP-IR menu. I use a different then default setting for my MK II to get the sharpest view possible.
And it bears repeating for anyone who reads this thread that the order for best results for the IR fixed objective focus units, at least the one that works best for me, is ocular focus then digital focus then ocular then play a little with the digital focus to see if more improvement can be had.
Keep in mind too that contrast adjustment effects apparent (but not actual) focus. The more contrast the less "smooth" the view, the less smooth the view the more it seems focus needs adjustment, when the route to a better view is less contrast.
Hope this helps!
JPK