9 out of 10 points and recommendedOutstanding optical and mechanical quality.Needs to be 12mm at the wide end.
Have replaced it with the Olympus 12-100 Pro but miss 2 features: 1) the longer reach, 2) the use of teleconverters. As crazy as it sounds, it works very well with both the EC-14 and EC-20. With the EC-20 AF was accurate on the EM1 in good light. No hunting.reviewed May 21st, 2019 (purchased for $750)
For anyone considering an Olympus or Panasonic 14-140/150, this lens is vastly superior. Though still a bit pricey on the used market.