Phyiscal Camera; Field of View issues

[kweechy]

If you set up a VRay physical camera with a 36mm film back and a 50mm focal length, it registers a field of view of 35.473 degrees. In reality, this number should be 39.6 though.

I've tried setting the film back to the diagonal size of a 35mm frame as well, but still the numbers don't work out. Any idea what's up?

[Zdravko]

Like in the real photo cameras there is one more factor that effects the FOV, which is Focus distance. FOV = f( focal length, sensor size, focus distance, zoom factor)
If you enable specify focus distance option and correct it you should get the focal length which you are after (make sure to disable Specify FOV).
Also, you can control focal length manually.