I did not abstain and ordered the lens 16KP 50 / 1.2 also known as 16KP RO 109 from e-bay from Ukraine. It seemed in the ad that everything should work with my current M42 -> Nex adapter. However, when the lens came, I realized that with a large adapter, I wouldn’t have the ability to focus to infinity. After a little searching online, I found that there are “slim” type adapters. I also found how this lens has been adapted by other Sony users. In my case, a slim M42 -> Nex adapter and an 18mm macro ring were enough. After assembly of all of the components the lens seems to deliver good results. Though the lens is very sensitive to the sun, so I will try to put on a lens hood.
I got a box like this, there was dust inside and the lens itself.
In the picture we see what was in the box. The focusing mechanism made by the Ukrainian and the lens itself.
The lower part was also cut down near the glass.
On the left a M42 18mm macro ring, on the right "slim" M42 -> Nex adapter.
The ring is screwed into the adapter.
The lens is also screwed on.
Well, here’s how everything looks on the camera itself.
Finally a test photo, a perfectly "twisted" background.