In summer 1931, another focal length was added to the Leica I with the introduction of the Elmar 90 mm f/4. Owners of a Leica I C were now able to chose from five universal thread mount lenses, offering the focal lengths of 35 mm, 50 mm, 73 mm, 90 mm and 135 mm.
Like its predecessor, the Elmar 90 mm f/4 consisted of four elements in three groups. The initial 'fat' version was replaced in 1933 by the 'thin' lens model – which was compatible with the integrated viewfinder of the new Leica II (introduced in 1932).
In total, six main versions of the Elmar 90 mm f/4 were produced until its discontinuation in 1964.