I just picked up a Dagor to use on my 9x12 camera and have read that it has a large coverage, even up to 8x10, stopped down. Is this correct? Also it doesn't have a series number, just Goerz, Berlin Anastigmat-Dagor. I think from the serial it is early 20's. So, this is a nice lens yes, as in famous Dagor? These 20's lenses are becoming my favourite, Tessar and Heliar also, wonderful.