If you do landscape type of photography (focused at or near infinity), and do no wish to spend 2700 € on a Fujinon GF 110/2 lens (for GFX cameras)... The Contax Zeiss Sonnar T* 100/3.5 at aperture ƒ8 is nearly identical in sharpness like the Fuji native counterpart.
It is truly a sleeper lens !
There is almost no difference in sharpness really. The little that you might spot, you can compensate with the sharpness slider. I do notice that the plane of sharpness seem to lean a tiny notch backward at the very borders. Sharpness-wise, the difference is extremely small (if there is any).
I made identical images with both lenses - and it was really fascinating to see... how similar both images where. Given how cheap the Contax Zeiss Sonnar 100/3.5 lens is (200 Euro), and how small in size and light in weight... it poses a serious alternative to GFX photography in the (fullframe equivalent) 85 mm focal range.
It is one of the rather few lenses that truly cover the GFX sensor ENTIRELY all the way into the corners. And sharp, especially when stopped down. That is a really feat for a 40+ year old lens made for 35mm Contax cameras. At ƒ8 there was no corner shading what so ever, just saying. It acts literally like a mediumformat lens covering a 33x44 mm sensor.
Aperture ƒ 8.0
Both images below were taken at ƒ8.
Now I don't know how the Carl Zeiss lens would perform on a GFX 100 type of camera with 102 MP sensor. My GFX 50sII has an older 51 MP sensor - and the resolution between both lenses are really very good !
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