Inverse of fovToFocalLength — the horizontal FOV in degrees
a given 35mm-equivalent focal length corresponds to. Currently used
by the FOV-preset table shape only; exposed here so the table-build
round-trips cleanly in tests.
Parameters
focalLengthMm: number
35mm-equivalent focal length in mm. Must be
strictly positive; values ≤ 0 produce a non-finite or 0 FOV.
Inverse of fovToFocalLength — the horizontal FOV in degrees a given 35mm-equivalent focal length corresponds to. Currently used by the FOV-preset table shape only; exposed here so the table-build round-trips cleanly in tests.