Carl Zeiss Jena Protarlinse
I bought today a fascinating lens at a flea market . It is called Carl Zeiss Jena Protarlinse. I've been googling for any information concerning it for the most of the day, but I still have some question about it that you might be able to answer.
From what I've found it seems to be a Large Format lens from the very beginning of the XX century, made from four elements in two groups.
The specimen I have is made of two halves, do you understand correctly that a shutter is to be placed between them?
Can I somehow deduct its age from its serial number?
The most saddening part about it is that the lens' condition is awful, it loooks as if one was digging trenches with it. The diaphragm leaves are all rusted and torn, 100% FUBAR. I'm thinking of removing them altogether and try to shoot with the lens fully opened. Opinions, ideas?