Quote Originally Posted by Jonathan Huyer View Post
It looks really good but I haven't been able to find any reports of how much coma it will have in the corners. That can really wreck star images.
I doubt you will see such reports until the lens is actually released at the end of the month. The MTF charts suggest that astigmatism is low, which is a good sign. Overall, the 20mm seems like a close sibling of the 24mm and the latter lens controls coma very well.