Lens shift value?

The documentation states:
Lens shift - allows the simulation of shift lenses for 2-point perspective. Changing this parameter is similar to applying a Camera correction modifier.
which is just taken from the 3ds Max documentation.
Does anyone know what the real world unit for the value in the lens shift is?

Thanks

It is a coefficient, so it’s just a number - it does not have a physical real-world unit.

Best regards,
Vlado

Thanks, luckily it ended up not being needed. Is there a way to input a cameras tilt value (not shift) and have it correlate to a real world unit?

Thanks