I used a tripod and custom white balance.
Shots are in JPG. No post processing of any kind.
Contrast, Sharpness, Saturation are set to "0" on my K10D.
Image Tone is set to Natural.

SMC Pentax-A 50mm f1.7 @f1.7


Zeiss Jena Tessar 50mm f2.8 @f.2.8 (borrowed from a friend)


Industar-50-2 @f3.5


Volna 50mm f2.8 @2.8


Helios-77M @1.8


Mamiya Sekor 50mm f2 @f2


MC Pentacon 50mm f1.8 @f1.8


Helios-44-2 @f2


Mamiya Sekor 55mm f1.8 @1.8


Vivitar 55mm f2.8 Macro @f2.8



I personally prefer the Volna-9. The OOF highlight rings are not that harsh.

Also noticed that the Industar-50-2 and the Carl Zeiss Jenna Tessar bokeh looks very similar. AFAIK these lenses share the same Tessar optical formula.

The Volna-9 does look nice here. For a tiny pancake, the I-50-2 is pleasing to my eye, probably being less sharp wide open than CZJ Tessar helps for bokeh. Thanks for posting.

Here are some informal test shots I did along the same lines...

http://www.markhahnphotography.com/russian/f28_lens_tests/normal_lens_tests28.htm

I like the Volna, as well. I'm seen similar comparisons where the Volna has distinguished itself from the group in the same way.

Here are some more..
The Pentacon and the CZJ Tessar allow close focus up to 0.33m and 0.35m respectively.
So in this comparsion all the lenses are at around 35cm distance from the test object.

MC Pentacon 50mm f1.8 @f1.8


Vivitar 55mm f2.8 Macro @f2.8


Volna 50mm f2.8 @2.8


Zeiss Jena Tessar 50mm f2.8 @f.2.8


Again I prefer the look of the Volna-9. It's bokeh is smoother than the rest and the highlight circles are not that harsh.

For those who are interested in f/2.8 shots, I already took them but did not post them earlier, so here they are now:

MC Pentacon 50mm f1.8 @f2.8


Pentax 50mm f1.7 @f2.8


MC Pentacon 50mm f1.8 @f2.8


Mamiya Sekor 55mm f1.8 @2.8



Mamiya Sekor 50mm f2 @f2.8



Helios-77M @2.8



Helios-44-2 @f2.8



I notice that at f/2.8 the Helios-44-2 has the roundest bokeh among the rest of the faster (f/2 and faster) lenses and that's because of the 8 blades aperture.


One of the reason I did this comparison is that we usually see bokeh from individual lenses but it is not very often that we get a comparison of multiple 50s.