I've been using the TechArt Mk III Contax G to E-mount and other than some regular system lock-ups, have been pleased with it.
I did notice an odd halo effect in some images (usually against a bright blue sky or white background) but chalked it up to the lens/sensor performance.
Today I received a cheap Fotodiox MF adapter and the halo is completely absent. I also noticed that images with the Fotodiox were warmer.
So on my copy, the TechArt is doing some not so great things to all three of my lenses: 1. Internal reflections generating a Halo effect 2. Color temp change
Has anyone else with the TechArt noticed the Halo? See image below.