The Leica 90mm f/2.5 Summarit-M Lens is a fast telephoto lens that is part of the Summarit-M class of affordable rangefinder lenses. This lens is ideal for portraiture and photojournalism, or for quick snapshots when you want to take pictures inconspicuously from a distance. Summarit-M lenses are designed to offer traditional Leica optical and mechanical excellence, while positioned at a price level below the current M ASPH lenses. With a maximum aperture of f/2.5, and by applying classical and proven spherical lens designs, these lenses provide excellent quality. These features also result in a very compact design. This lens has been updated with the "6-bit" coding, which allows the digital M camera to read this information optically and to identify which lens is being used. The camera can then (optionally) apply a "final stage" software based vignetting correction