German gunsights and shift+f1

[TinyTim]

The field of view does not change. The point of view moves forward and to the side a bit, where (in some planes) more of the field of view is obscured by the cockpit framing and panel which might give an impression that FoV changes. But it doesn't, it stays exactly the same. It's easy to confirm this by observing distant objects and switching between normal and Shift-F1 view.