
It was a small, lightweight camera using 24 mm × 36 mm film rolls of 36 shots, establishing dynamic live photography. The Leica, a 35 mm camera developed by Leitz's collaborator Oskar Barnack with the interchangeable lenses of Max Berek was distributed worldwide from 1925.

The large Leitz Ortholux research microscope with built-in illumination (1935) also became a great success. Leitz initially devoted himself to the development of new microscopes, in particular the world's first binocular microscope that could also be used for high magnifications, which was launched in 1913. After an apprenticeship as a mechanic in his father's business and training as a merchant, Leitz joined the company as a partner in 1906 and became sole shareholder after his father's death in 1920.

Ernst Leitz was the second son of the entrepreneur Ernst Leitz I.
