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FIELD OF VIEW GUIDE!
--Please remember FOV is largely personal preference! This setting just finds your "natural" fov, below of which you might start to feel motion sick--

1. You need 3 measurements in the same unit of measurement: (i) Top of monitor to eye when sat normally (34 inches for me) (ii) Bottom of monitor to eye when sat normally (37 inches for me) (iii) Height of monitor vertically (13 inches for me).

2. Put these numbers into this calculator: http://ostermiller.org/calc/triangle.... with the top measurement on the left "side" box, the bottom measurement in the right "side" box and the monitor height in the bottom "side" box.

3. Make a note of the top "angle" number i.e. the one nearest to where it says "angle units" (if you put in my numbers you will see it says 21 degrees in the top "angle" box)

4. Nearly there. Now you just need to convert the VERTICAL fov to HORIZONTAL fov by finding you monitor aspect ratio and dividing appropriately. i.e. I have a 1920x1080 24 inch monitor which is a 16:9 ratio monitor (all 1920x1080 square pixel monitors are).
This means I divide the 21 degree Vertical FOV by 9 then multiply by 16 = 37.3 degrees

5. Now you just need to convert this number to radians, which is what games use i.e. I googled "37.3 degrees in radians" and got 0.65 = 65 degree FOV in games. Anything less than that is likely to make me feel motion sick. I currently have my FOV set to 80 degrees at is seems the best balance between visibility at distance and good awareness.
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