# Field Of View Angles In P3D

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How do you set the actual Field Of View (FOV) angles in P3D?

There should be settings for both the vertical and horizontal field of view.

This is different from the zoom.  I mean the actual angles from the viewpoint (i.e. your head) to the image viewing plane (i.e. the screen).

For example, if the semi-major ( half horizontal ) axis of the display is a, the and semi-minor (half vertical) axis of the of the display is b, and the distance from the viewpoint to the image plane is λ, then the FOV angles are Ωa and Ωb are

Ωa =  2 * arctan( a / λ )

and

Ωb = 2 * arctan(  b / λ )

If the FOV angles are set properly, then what you see on the display should match the actual view of what you would see in the real world if you were looking through a window the same size as the display.

From a post I made elsewhere....

The field of view is inversely proportional to the zoom factor, ie as the physical FOV decreases the zoom level increases and vice versa

to calculate the zoom (Z), you use (h=screen height, d is distance from your screen)

Z= 34/ 2 arctan (h/2d)

this breaks down in my case to;

Z= 34/ 2 arctan (52/2x130)

34/ 2 arctan (52/260) 52/260= 0.2

34/ 2 arctan (0.2)

arctan of 0.2 = 11.31

2 x 11.31 = 22.62

34/22.62= 1.50 zoom level required for my viewing distance of 130cm to render objects in scale.

example 2, to calculate a zoom level if you sit 85cm away from a 70 cm screen

1) divide your sceen height by your actual viewing distance x 2 eg 70/170 = 0.411

2) find the arctan of 0.411 which is 22.380

3) multiply by 2 which gives 44.760

4) divide 34 by 44.760 gives a zoom level of 0.75

you need to zoom out becasue you are not seeing enough of the fsim world through your displays, on this occasion so the preference would be to move your viewing position back to match the zoom level 1

To set the default zoom level, you can navigate to the camera.cfg located in the sims app data folder (same place as the fsx/p3d.cfg) and alter the default zoom to match your calculated zoom for each camera you use.

I find that the higher zoom means I have lost some of the view in front of the aircraft, therefore I have compensated by pitching the camera down a little by adjusting the pbh value in the camera.cfg also

Now for the final spanner! I actually dont like zoom 1.50! so I am using 1.30 which looks better because the depth of field is lost the more you zoom in so a compromise was needed!

Hope this helps, have fun

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• Tom Allensworth,
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