Quote Originally Posted by Ian Grant
Actually the major problem with the Summar is that the type of glass used was comparatively soft and very prone to scratching/cleaning marks which reduced its contrast & sharpness. The Summar lens on my IIIa when I bought it 30+ years ago was awfull, I quickly bought an Elmar to replace it. Since then I've found an excellent Summar, but in reality films were nowhere near as good when the cameras & lenses were manufactured and the photographers of the time did not have our current expectations of quality from 35mm.

My 12" Dagor of similar vintage was factory coated after the war, I wonder how much better the Summar would be if it had been similarly coated.

Used as it would have been you'll get excellent results, but unlike modern multicoated lenses you can't shoot into bright lighting, unless you want the flare!
I have a Summar which is clean and excellent, also one which has been coated but untested. I have been told that Summars varied in quality a lot.
A friend a I did a little lens test some while ago and yes the later Summicrom performed best but the real surprise was some old Takumars with the radioactive yellow elements-almost too sharp