A Group of M42 Mount Lenses, including two Carl Zeiss Jena Electric MC 135mm f/3.5 lens, three Carl Zeiss Jena MC 135mm f3.5 lenses, a Tair-11A 135mm f/2.8 lens, a Pentacon 135mm f/3.5 lens, Meyer 50mm f/2.8 lens, Pentacon Electric 135mm f/2.8 lens and other examples, barrels G, elements G