I'm going to hazard a guess that I am not alone among collectors to have become fascinated, at some point, with Tessar formula lenses and its reputation for sharpness.
The interest in the lens goes beyond obtaining a piece of equipment with a high level of technical performance.
Indeed, if you are like me, you may have wanted to try real Tessars - that is, a lens made by Carl Zeiss in Germany as opposed to licensed versions made in Japan - not because it is sharp but because it is authentic.
One of the great attractions of camera collecting and photography is the constant search for authenticity - regardless of whether it is an uncropped, full-framed masterpiece of street shooting or gear that has the seal of approval/use of a well-admired photographer. I am certain I will never be able to find for an affordable price a Konica Omega 6x9 because it was featured in a documentary film about William Eggleston by Gus Van Zant.
Similarly, it's hard to find cheap Tessars. Instead, as a bottom-feeder collector who gathers the underappreciated or insanely obscure, I have kept my eyes out of Soviet copies of the Tessar design. And I found one, the Industar 50-2 50mm f3.5 (above) threaded to be used on Pentax M42 or Praktica mount SLR bodies. It should not be confused with the Industar 22-2 50mm f3.5 which is a Leica thread mount lens for Leica rangefinder-styled bodies. That lens has an Elmar formula.
Early this month, I finally had a chance to use the lens on a digital body, a Nikon D40, making do with the unorthodox use of a M42-Konica AR adapter (no infinity focus).
Wide open, which is my preferred way to shoot, the Industar showed a lot of glare and chroma. But once I started to stop down to f8, the lens looked great to my non-technical eyes.
At f16 to photograph the Voigtlander Vito B (below), the ersatz-Tessar did very well. The noise can be blamed on the ISO setting of 800.
All of this suggests that the little pancake Industar would be best used in sunny conditions. However, because of coatings, I suspect is is susceptible to flaring.
Note: the top image of the Industar was taken with a Vivitar 50mm 6 element enlarger lens at f2.8.
So you see, the experiments continue.