I am talking about the hold down zoom when in 3rd person, not the scope zoom.
So when sitting on the gunner seat, go into 3rd person, hold down the right mouse button, then the zoom will just go into the vehicle instead of before were it zoomed into the distance.
This is how it looks when zooming:
UH1H:

LAV-25 as driver

LAV-25 as gunner

As you can see in the screenshots, when zooming on the Heli and the LAV (as the gunner) it zooms in a way that is basically useless for spotting anything.