4 ms·

Also from the article, his actual PD is 69mm...

• Spare_account 9y ago
  OK, I'll admit I didn't get that far. But that means the method was accurate ±8mm? Still not ±4mm... (Unless I don't understand the ± notation)
  • maxerickson 9y ago
    1 face probably isn't enough to characterize the accuracy of the method.
    • Spare_account 9y ago
      Well that kind of invalidates the entire article then! ;-)