More initial results. They aren't surprising but it is good to learn that all I've heard is true.
G1, Contax G Planar 45/2:
A Zeiss made in japan, very sharp, as it often is with Zeiss lenses. When running a series of images through IMA-test the lens performed as good as other classic very good lenses (comparable to OM90/2Macro (sharper than Leica Elmarit-R 100/2.8 Macro APO) and a tad better than the OM50/2Macro and ZD50/2 Macro also if not visible in small prints).
The borders are sharp at f/2 and f/2.8, then they are very sharp.
The corners are sharp at f/2.8 and very sharp at f/5.6.
As IMA-test targets are even more boring than USAF charts I post the later:
The lens also passed a simple flare test. Not only passed, it performed among the best I have seen. When mounting a filter it got worse but not worse than one can predict. Below is the f/2 result, no filter:
Very very good
In real life it means one doesn't need to worry. It's great with a late standard construction. Here is a simple sample from a short walk yesterday, shooting distance may have been around 8 meters or so:
Wide open, in a back yard of an office, overcast. I know, Barnack says "No statues" but...
And finally, a 100% crop taken from the image above:
It's like having a new reference lens.