From: Colorado

Not guaranteed to be 100% dust and moisture resist

June 04, 2021
Optical it is excellent. That covers boka, sharpness, distortion on a A7R4. It is light and uses just 67mm filter size. One lens went into the water for one second on a rafting tour. It fogged up in few minutes and went back for repair. Conclusion Sony's foot note above is very correct and serious. Perhaps such a short event shows that this lens isn't dust resistant. Long term use requires to keep lens and camera totally away from the elements. For this GM top of the line lens that is very restrictive to its professional use. For home use it is outstanding in optical quality and recommended. For professional use it has insufficient dust and water resistance. That explains my rating.