The name Summilux is used by Leica and Panasonic Lumix to designate camera lenses that have a maximum aperture of less than f/2, typically f/1.4, but greater 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.[1] The first Summilux was the 50 mm of 1959, followed by a new 50 mm Summilux design in 1961, whose optics remained unchanged until replaced by the 50 mm Summilux-M ASPH of 2004. [2]
The Summilux lenses have a maximum f-number of f/1.4, f/1.5 or occasionally f/1.7. This one to 1.5 stops lower than Leica's Noctilux lenses, but the Summilux lenses are smaller as a result.[1] Summilux lenses are designed for low-light photography.
The Summilux lenses are less expensive than the Noctilux lenses, which has a smaller f-number.[1] However they are bigger, heavier and more expensive than the Summicron.