Page "Leica Camera" Paragraph 4

The Leica went through several iterations, and in 1923 Barnack convinced his boss, Ernst Leitz II, to make a pre-production series of 31 cameras for the factory and outside photographers to test.

Though the prototypes received a mixed reception, Ernst Leitz decided in 1924 to produce the camera.

It was an immediate success when introduced at the 1925 Leipzig Spring Fair as the Leica I ( for Leitz camera ).

The focal plane shutter had a range from 1 / 20 to 1 / 500 second, in addition to a Z for Zeit ( time ) position.