Over time, I have aquired a good collection of enlarger lenses through my wheeling and dealing adventures. I have a bunch of El-Nikkor and Rodenstock lenses and was just wondering if there was a place to find out the dates and elements of the El-Nikkor's from the serial numbers on them. The Rodenstocks don't have a number that I can find.

Any one know of a place to look for some info on these. I have searched some on the internet but haven't found anything much about year or elements from the numbers.

Could use some knowledgeable help here.

I do know that from a little testing with each that I can't tell any thing different on prints up to 11x14 from 35mm negatives from any of them. My eyes are not the best anymore but I would like to keep the best ones and let the others go to others that can use them.

Any help on this would be appreciated.