Leica I

The Leica I is an early compact 35mm still camera manufactured in Germany by Ernst Leitz GmbH. It was commercially introduced at the spring fair in Leipzig in 1925, having been developed from earlier prototypes including the Ur-Leica, created by Barnack in 1913, and the Prototyp 1 from 1923. The camera proved instrumental in establishing 35mm film as a viable and serious format for still photography.

Marketing of the camera commenced in the mid-1920s following years of prototype development dating back to the first years of the twentieth century. A defining technical innovation of the design was orienting the image frame sideways along the 35mm film strip, departing from the conventional cine-camera format of running frames across the film. The camera was followed by the Leica Luxur and Leica Compur variants, with a combined total of 60,586 units produced across the Leica I, Luxur, and Compur models. While early production examples were fitted with a fixed lens, interchangeable lenses were introduced for these cameras in 1930. Further iterations of the Model I were later produced, though they achieved limited sales compared to subsequent lines.

Designed to be compact and portable for activities such as hiking and cycling, the Leica I utilised a focal plane shutter and collapsible optics. As a pure viewfinder camera, it is distinguished from succeeding Leitz designs by the complete absence of a built-in rangefinder, an addition that first appeared on the Leica II in 1932. It also predates the slow-speed shutter controls introduced on the Leica III in 1933. Before the Second World War, Leitz models of this lineage were regarded alongside Zeiss Ikon Contax cameras as leading 35mm instruments.

The lens is either fixed or, on examples made from 1930 onwards, interchangeable.