I am using the a7R. Tried the 28 yesterday and LCD looked fine. Have not yet hauled out the 21, but will probably tomorrow. All my adapters are Metabones.I would love to see your comments and pictures concerning the Contax G lenses, especially the 21mm (it is not reported to do very well alas, but I would still like to see the results). Are you using a A7r or a A7 ? The A7 would probably be more forgiving.
Today
M 21/1.4
M-WATE
M-MATE
R 80/1.4 maybe
R 180/3.4 maybe
APO50 maybe
Cannot find the way to turn off as many in camera functions as possible. I am now shooting RAW+JPEG so at least I can see the jpegs.