Petri Kuribayashi cc 50/2 & Lens turbo

The lens was in Petri bayonet, then modified to M42.
I use it on my Sony Nex 5 and Zong Yi lens turbo 1rst gen.
No degradation in term of sharpnes at center with this combo.

Petri Kuribayashi CC 50/2

Petri Kuribayashi 50/2 in M42 mount is sought after these days. People want the out of focus area looks like Meyer. So they called it Domiron copy. refers to the similar bokeh. Actually Kuribayashi 50/2 was made before Domiron. 1958-1960. So no way they copied Domiron (made 1966-1968)
This lens was made along with the camera, after M42 series. It use bayonet mount. You can judge these samples, is it same or close to M42 predecessor? or not.

First sample right after I opened the box,  without proper adaptation, handheld in my Sony NEX5

Now, it's attached on my helicoid adapter to NEX

Petri 50/1.7 MC

The lens comes in Pentak K mount, appearance looks like Cosina Lenses. maybe Cosina made (?)
I read somewhere that some Petri lenses were made by other maker.
The results also looks similar to Cosinon 50/1,7
Nice lens by the way. sharp at wide open and good at stoped down at edges.
show some purple fringing but acceptable.

Petri Orikkor Kuribayashi AC 4,5cm/1,9

This one is from Petri range finder camera

I like this lens. sharpness, bokeh, 3D, colour, contrast...what else..?

cropped to see more detail