All 35mm lenses, here we have the least expensive contender Color Skopar 35mm Pancake PII
In the beginning I can say the Biogon C is sharper and has better rendition of blurred backgrounds, while the Skopar is very close. The only one that is different in rendition of color and blurred areas is the Summaron. I can’t decide what lens will be the keeper yet.
For current prices of these lenses, check amazon: