It definitely seems to be tied to the aspect ratio. I don't think the developers ever planned on people using triple widescreen monitors :)
I downloaded the source code and have been digging through to see if I can manually override the FOV, but haven't found anything.
Ditto -- same issue for me. i"m trying to play on nvidia surround mode with 3 1920x1080. Works fine if i set the FOV to auto, but when i set it to manual i get the same loss of detail as everyone else in this thread