When in a man class vehicle (a.k.a. soldier) and not in optics you are able to use the commands Zoom Out (Toggle) and Zoom In (Toggle) to set your FOV to the currently allowed maximum and minimum respectively. The default keys are 2x Numpad_- and 2x Numpad_+, again respectively.
However, for some reason these functions do not work inside Car, Armor, Air, Static, etc class vehicles. Numpad_- and Numpad_+ increase and decrease FOV but the toggle commands do not have an effect.
Can we get the toggle zoom commands in all vehicles? It would make HMMWV driving a lot easier for one.