How to get real world focal length (mm) from unreal FOV

Hi guys,

I am having trouble on calculating real world focal length in mm from the unreal engine FOV value.
I using a timeline, that passes values from 1 to 170 over to a scenecapture2d component. I display the value with a textrender component in the very end.
On the way I need to convert the FOV to a focal length value with a math expression. But this is where I am stuck.
I used several FOV to Focal Length equations in the blueprint, but they don’t display the right values. I even get negative values because of the trigonometry.

Is there any way to get real world camera information from the few parameters the unreal camera has to offer? I don’t even know, if it is based on something real (like a 35mm camera) etc.

Would be great is someone could give me a hint.


Did you ever get any traction on this christoph.pixo? I’m curious about the same thing. When I import camera data from Maya the Unreal FOV is slightly off.