Summicron

The Summicron is a family of Leica M-mount fast prime lenses produced by Leica Camera AG (formerly Leitz). Introduced in the 1950s as the successor to the Summitar, the Summicron line covers a range of focal lengths and is known for high sharpness, contrast, and build quality. The name Summicron typically denotes light, compact lenses with maximum apertures around f/2.

The most famous member is the 50mm f/2 Summicron, widely regarded as a benchmark lens for the M rangefinder system. Over the years Leica released multiple variants for the M series (designated by Type I through modern iterations), refining coatings, geometry, and mechanicals. In the late 1990s and 2000s, Leica introduced ASPH versions—such as the 50mm f/2 ASPH—with aspherical elements to further improve sharpness and correction, particularly at close focus and wide apertures.

Additional focal lengths have been added to the line, including shorter and longer focal lengths to suit documentary and street photography, all sharing the general design philosophy: compact, robust construction, and strong optical performance with minimal distortion for their class.

The Summicron remains in production and is widely used on Leica M bodies today, both in film and digital formats. It is valued for its combination of speed, image quality, and the classic Leica look, and is frequently compared with contemporaries in the same focal length range.