Summilux

The name Summilux is used by Leica and Panasonic Lumix to designate camera lenses that have a maximum aperture brighter than f/2, typically at f/1.4, but dimmer than f/1.0.

The lens has been in production since 1959 and carries on to the present day.

The name Summilux is a combination of Summum, which is the Latin word for highest, while Lux is for light.

[2] The Summilux lenses have a maximum f-number of f/1.4, f/1.5 or occasionally f/1.7.

[1] Summilux lenses are designed for low-light photography.

Leica Summilux-M 50 mm f /1.4 Version 2 (1961 – 1968)
Leica Summilux 35 mm f /1.4 Version 1
Optical Diagram of Leica Summilux-R 50mm f/1.4 II lens.