The Hamburg City Council, however, imposed as its conditions that the planetarium's projector be fully modernised in the Zeiss factory at Oberkochen, and that Johannesburg would in due course have a new planetarium built for Hamburg.
The first Biogon (2.8 / 3.5 cm, unbalanced) was created in 1935 by Ludwig Bertele, then referenced by designer Zeiss Ikon Dresden, the Contax created as a modification of the then Sonnar. It was developed by Carl Zeiss in approximately 1949 and manufactured in Jena, then a redesign in Oberkochen. In 1951 a new Biogon with a 90 ° angle (Super Wide Angle) was also designed by Ludwig Bertele for Carl Zeiss, which opened the way to extreme wide angle lenses.