[netrex]

I don't know if they have got better, but I have an earlier copy of their 8mm fisheye for DSLRs and the focus scale on that wasn't even close. I wasn't alone on that. Other people realised you can disconnect the outer part of the focus ring by undoing some screws, and then align it correctly before fixing it once more. I did that to mine and it is close enough now. See it as like focus micro-adjust for manual lenses Again, I don't know if this might affect their more recent lenses, but certainly you can test it to see e.g. put a target exactly 1m from the focal plane, and see where you have to turn it for best focus.


Otherwise... I'd probably use magnified live view to nail focus on the primary subjects. If there isn't time for that, stop down and don't worry about it.

They had this problem on the 14mm f/2.8 as well, I was lucky however, and it was spot on