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Hi,
Converting a camera from horizontal aperture to vertical aperture seems to result in a strange inconsistency.
The screen res we are working with is 1280x533 which is approx a 2.4 aspect ratio. Therefore a horizontal aperture camera of fov 72degrees is 30degrees in vertical aperture: 72.0/2.40=30.
However when changing the camera into vertical aperture and setting it to 30degrees, it results in a subtly different projection. This does not make sense to me as it should be the same.
Everything else between the cameras is identical, in fact one is a duplicate of the other.
* Is MB in error when projecting?
* Is the 30degree value wrong?
* Is there some setting I am missing?
Cheers,
John.
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I think I have realised why:
I was converting the horizontal aperture using the common method of dividing the fov by the aspect ratio.
In truth the ratio between the horizontal and vertical fov is not the same as the aspect ratio. Using trig I found it is actually:
focallength = ( width / 2 ) / tan( FovH / 2 ) = ( height / 2 ) / tan( FovV / 2 )
FovV = 2 * ( atan( ( height / 2 ) / focallength ) )
FovH = 2 * ( atan( ( width / 2 ) / focallength ) )
This yields an equivalent image in both vertical and horizontal apertures.
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