the first prototypes of the new 7-lens Summicron were marked as Summitar*. I have an uncoated Summitar example from 1939. In the centre it is very sharp, towards the corners the sharpness gets less, it has a softer contrast compared to modern lenses and is rather prone to flare if shooting against the sun but other than with more modern coated lenses I have the impression that you even get more details in the shadows. Sometimes the extensible barrel can be worn and the lens is not parallel to the film plane and you can get a slightly shifted position resulting in a sliding sharpness from left to right or up to down. The front lens is made of a very soft glas type and therefore most lenses have scratches from over-cleaning.