3E85D6FA.1F6DBC09@gmx.de...
> I don't know how Blender calculates a camera angle from a given
> focal length but it has to assume a certain film format for that.
>
> Christoph
>
I don't know more about blender but usually it is spoken of a 35mm  (36x24mm
image) film in that discussions.
so  as angle  means horizontal angle :
Angle of View = 2 * ArcTan(Size/ (2 * Focal Length * (1 + Magnification)))

assuming the lense is normal (not a macro one), Magnification can be
considered as 0.
 so
Angle of View = 2 * ArcTan(Size/ (2.Focal Length ))
and
Focal Length=(Size/2)*cotan(Angle/2)

But my maths are far away in the mists of ages so I can be wrong

Marc

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