I'm not sure if the title of this thread accuratly describes the problem or not, however, I think there are a few FOV issues being convoluted, let me try to re-iterate the problems and see if I can explain what I think is happenning....
Firstly, the FOV game setting only applies to multiplayer, the single player FOV is locked at what is supposed to be 65 degrees vertical FOV (I think).
Note that in previous battlefield games, BFBC2 for example, the FOV setting (GstRender.FieldOfView) represented the vertical field of view and not the traditional horizontal field of view like in the Quake engine for example. I'm not sure about BF3, perhaps someone who knows for sure can clear that up.
Now, moving on to BF4, in my case running on a 16:10 screen, the Field of view game setting (GstRender.FieldOfView) does not represent either horizontal or veritcal field of view. I have confirmed this by experimentation and measurement in game moving the mouse round and using the minimap to see the angles etc...
If I set the FOV in BF4 to 90, the actual horizontal FOV I get is about 105 degrees. If I set the FOV in BF4 to 65, which is what you would expect to have to set the vertical FOV to get a horizontal FOV of 90 at 16:10, the FOV is more like 80 degrees. Through shear trial and error I worked out that the FOV setting in the game has to be set to about the value of 80 for me to see a real horizontal FOV of 90 on a 16:10 screen.
Oh also note that after changin the FOV setting in the options manu in BF4, you must ADS and back out again for the new FOV setting to take effect.
So what on earth is going on here? The FOV setting in the BF4 options menu is either using some strange notion of a diagonal FOV or is hard coded to derive horizontal FOV from vertical FOV with a fixed aspect ratio that doesn't match the aspect ratio of my monitor.
Try it and see for yourself.....
Load into an empty server (not sure if it works on the test range but maybe), find a straight wall that faces due east west or north south, align the view so that a section of the wall takes up exactly the width of the screen and perpendicular to it. Then turn so that the left edge of the wall is now alighed with the right edge of your screen, the angle you have turned through is the real horizontal FOV being used to render the scene. Use the minimap to see how far out it is.
