Sonnar 135mm f/3.5 (1600F/1000F)

The short telephoto of the 1000F outfit, and a simplified Sonnar: five elements in three groups, where Bertele’s original for the Contax used six or seven. Zeiss’s factory sheet gives the true focal length as 134.34mm at f/3.48 and the back focal distance as 89.09mm; the lens covers 34°, focuses to 1m, and weighs 520g in a barrel 80.5mm long and 74mm across.

The design is credited to Lange, Eismann and Jahn, with a German patent filed on 5 April 1954, and it uses a barium flint for the rear element. Cavina counts about 2,100 made in six batches from 1953 or 1954 onward — a substantial number by the standards of this system, where a lens selling two thousand copies was a success.

It sits on the M60×6 three-start thread of the 1600F and 1000F. Nothing from the later V system fits, and this lens fits nothing later; the 1957 changeover was complete.

What the record does not settle is how it performs. Zeiss published the geometry and the coverage but the sheet carries no MTF, and no review of this lens on this camera has surfaced in any language consulted. The lenses that followed it in the V system are extensively tested; the pre-1957 Zeiss glass is known mostly through the cameras it came attached to.