I just got the Techart III adapter in the mail today. I also just purchased the 45 f/2 and 90 f/2 lenses. The 90 mounts and tries to AF. I can manual focus it. The 45 mounts, but will not AF and when I turn the manual focus wheel, it spins loosely. It is not engaged. There is no AF.
I have put it on several times. I've had Contax G lenses before on a Contax II and on a NEX with an adapter (which I unfortunately no longer have), so I know how to mount and unmount a Contax G lens properly.
I am not sure if I am missing something in the gibberish Chinese translation instructions. I have my lens AF on the shutter button. The rest, I'm not clear on. I don't know if the problem is with the 45mm lens or with the adapter or with me. I'm pretty sure that the adapter needs a software update because it is hunting a lot, but I don't want to go there till I figure out if I should send it back or not.
I have tried it on A7rII and A7II.
Any help would really be appreciated.