What is Doom 2 game camera focal length?
Many computer vision applications (including SLAM for VizDoom) rely on camera information. So I'm wondering what is Doom 2's camera focal length?
There's no focal length as the game rendering doesn't use a sensor/film; same focal length lens will produce different FOV depending on sensor/film size.
Typical FOV of Doom is 90 degrees; following the conversion table you're getting ~22mm if you assume 35mm/FX format, 14mm for DX format. Trying to use the screen diagonal doesn't make sense though.