Parfocalness can be emulated in firmware (by adjusting the focus as the zoom changes). What you probably should have pointed out is the opposite property: keep

Parfocalness can be emulated in firmware (by adjusting the focus as the zoom changes). What you probably should have pointed out is the opposite property: keeping the same focal length while changing the focus distance. This can't be emulated in software because camera lenses don't have a motor on the zoom (plus primes don't have a zoom). Some cine lenses do achieve this by moving a zoom-like group (I think all the ARRI master primes do) and not just by being telecentric on the exit side.