by pooka » Wed Aug 08, 2007 1:57 pm
The serial number might be helpful, but look for the QBM 4 notch anyway, or try the lens on a QBM 4 body. Martin Arndt of Marflex converted a number of my QBM 3 lenses a few years ago (using Zeiss parts). Since these are excellent professional lenses, I suspect a fair number of other users might have had their lenses converted from QBM 3 to 4 in the same manner by Marflex, Rollei-Werke, or others.