His developments received universal recognition and serve as a basis for considerable part of the optical designs used today.

Its basis was the optical scheme of the Ultrastigmat cinema lens, a modified Cooke triplet, which had been developed by Charles C. Minor in 1916 and produced by Gundlach Company.

The main purpose of Bertele's developmental work was to increase the light-gathering power of a lens as well as diminishing optical aberration.

The Ermanox with Ernostar f/2 was the first camera with sufficient speed and image quality for successful candid photography in natural or otherwise unaltered light conditions.

[citation needed] In 1932, a Sonnar variant with a faster maximum aperture of f/1.5 was developed, which was fitted to Zeiss Ikon's 35 mm Contax cameras.

[citation needed] As Zeiss in Dresden and Jena had become part of the Soviet Zone of Occupation in 1945, they were required to transfer their designs, as well as their machinery and staff, for training in Russia and Ukraine, where Sonnars were produced in vast numbers under the "Jupiter" designation, as some of the most desirable optical products made in Soviet Russia.

[citation needed] In 1946, Bertele moved to Switzerland, where he founded an optical bureau and began working at Wild Heerbrugg Company (now Leica Geosystems) in the field of photogrammetry and geodesic devices.

This lens, as well as 120° Super Aviogon, which appeared in 1956, won a great number of prizes and merited general recognition.

[3]: 151 In the same year, Bertele computed new optical designs for Carl Zeiss in Oberkochen, resulting in a Biogon lens with a 90° viewing-angle in 1954.