Does anyone know of a reference work which can offer reliable evaluations of pre-World War II German scopes? I have had enough experience with pre-World War II American hunting scopes to be able to make a quality judgement about the few options then available, such as Lyman, Noske, Belding & Mull and Unertl, but even in the World War I era there were a bewildering number of German hunting scopes on the market and being used with sniper rifles. I have been unable to find a discussion of the optical qualities, field of view and preciseness of adjustment for any of them.

I own a number of Zeiss and Hensoldt scopes and can form my own opinion about them, but other fairly common makes like Oigee, Goerz, Gerard and Voigtlander are a complete mystery. Any suggestions would be very welcome.