Zoom level to FOV conversion?

[pilotjohn 19]

Does anyone know how the zoom level (e.g. 40% 50%) in the settings correspond to the field of view (FOV) in the default pilot position, or what the formula is? I believe 1.0 zoom level in FSX was 34 degrees vertically (with wide screen true), or horizontally (with wider screen false). Is it the same in MSFS? 34 degrees horizontally by default, which would make the default 50% zoom level equal 68 degree FOV?

[DLP084 5]

Would be also interested in the correct 1:1 zoom value. 

[sidfadc 1,340]

I haven’t found any FOV settings and the default zoom for me doesn’t zoom in near enough, not useful for spotting airports in the distance etc 

[Mark1616 47]

I made an experiment with the C172 at the sunset. The difference in two headings, when the sun is at the left and at the right edge of the screen/view respectively, is the field of view (FOV). For the screen ratio of 3840x2160 (4k) and the zoom of 50%, the FOV is 100 degrees. This works quite fine with the eyes about 75cm from the 48" screen.

Edited November 22, 2020 by Mark1616

[pilotjohn 19]

10 hours ago, Mark1616 said:

I made an experiment with the C172 at the sunset. The difference in two headings, when the sun is at the left and at the right edge of the screen/view respectively, is the field of view (FOV). For the screen ratio of 3840x2160 (4k) and the zoom of 50%, the FOV is 100 degrees. This works quite fine with the eyes about 75cm from the 48" screen.

Did you use the cockpit view or external view for this?

Notice that the "zoom" is not the same for different cameras (thread).

[pilotjohn 19]

10 hours ago, Mark1616 said:

I made an experiment with the C172 at the sunset. The difference in two headings, when the sun is at the left and at the right edge of the screen/view respectively, is the field of view (FOV). For the screen ratio of 3840x2160 (4k) and the zoom of 50%, the FOV is 100 degrees. This works quite fine with the eyes about 75cm from the 48" screen.

So you're 30" from a 48" screen (which about 42" wide). This is a FOV of atan(21/30)*2 = 70 degrees IRL. The best immersion for the sim would be if you were to match this with zoom. I'm in a similar state, 32 inches from a 55" screen, and a high FOV in game doesn't feel right (compared to when I sit in the cockpit in real life). I've tried to match the sensation, and I've also done some empirical testing.

My testing involved slewing the aircraft to altitude, pitched down above a runway (swapping between slew and active pause in cockpit since the zoom factor between cameras differ), to see at what altitude I can see both ends of the runway (side to side). At KORS, which is about a 3400 foot runway, with a zoom of 55, I had to be at 2200 feet. This is about atan(1700/2200)*2 = 75 degrees of field of view.

[pilotjohn 19]

11 hours ago, Mark1616 said:

I made an experiment with the C172 at the sunset. The difference in two headings, when the sun is at the left and at the right edge of the screen/view respectively, is the field of view (FOV). For the screen ratio of 3840x2160 (4k) and the zoom of 50%, the FOV is 100 degrees. This works quite fine with the eyes about 75cm from the 48" screen.

I also just tried your method, and 55 zoom is roughly 75 degrees in cockpit (but not in Slew mode - you have to slew, active pause, switch to cockpit, rinse, repeat). So our two methods agree.

[Mark1616 47]

7 hours ago, pilotjohn said:

Did you use the cockpit view or external view for this?

Notice that the "zoom" is not the same for different cameras (thread).

It was in a cockpit view. Your method with the runway length is pretty smart (of course if length as a physical concept is properly implemented in MSFS ...).