I have been using it for some time now on the Sony a7r III with all my m42 lenses, especially with the beloved Helios 44-m4, and I have never encountered any problems.
25/01/2023
Purchased after rediscovering some used lenses from my father, it was a shame to leave them in a closet waiting for a better life. The M42 adapter to Sony E-Mount is perfect, if you follow the procedure of shooting without a lens, it will give new life to your lenses, especially if they are of excellent quality. I have not encountered any problems with crop or difficulty maintaining focus by the camera. Needless to say, you return to the sacred totally manual settings of focus, diaphragm and possibly zoom. The mounts are perfect and extremely solid but I do not think they are guaranteed on tropicalization due to non-original Sony mounts.
14/12/2022
10/11/2022
I wear it for months to fit the Helios 55mm lens onto a Sony A7. It works amazingly, it's metal and feels very sturdy.
16/10/2022
Sturdy connexion, strong build, no light leak. I now have four different models of those (MD, M42, M39 and PK) and am very happy with them. Some complain about the aperture marking from their lens not falling exactly on top of the barrel but slightly on the side... I don't think that it really matters when you know your lens well enough and it's not like they were underneath.
09/10/2022
Better looking adapter, and as easy to use for Sony E Mount. Clicks onto FD lenses with no hassle, feels sturdy and robust.
24/09/2022