Vigtlander Nokton 50mm f/1.5 Aspherical is a standard focal length manual focus prime lens for M-mount rangefinder cameras. For all other camera mounts, a specific adapter is needed. It is a compact (1.8") lens with an all-metal lens barrel and a particularly fast aperture--effective in low light situations and able to create shallow depth of field. Distance and depth of field scales are clearly marked on the lens barrel.