Description
The 21mm f/1.4 Leica Summilux-M Aspherical functions as a super-wide lens engineered for fast performance. The brilliant f/1.4 aperture produces an exceptionally shallow depth of field, and at a middle f/stop, it's focal reach is so terrific that complete intact scenes can be sharply reproduced. As a consequence of the floating element design, exceptionally high resolution is possible even in close-up spaces.
The lens allows for highly dramatic impressions, such as monumental foregrounds, strongly diminishing backgrounds with a wide horizon. Using this lens, the focusing plus metering are executed by looking into the camera's viewfinder, although the real framing is confirmed with an attached accessory viewfinder mounted on the camera hot-shoe.
An f/1.4 lens is not usually as efficient as the same manufacture's f/1.8 or f/2
lenses, even when both are stopped down to f/5.6. the lens with the wider
aperture is heaver and more expensive, so don't choose it as your standard
unless you are planning a great deal of photography poor light conditions.
There' plenty of reasons for using a wide aperture, but avoid buying a lens with
an aperture wider than you need.
Leica lens new updated "6-bit" coding
This Leica lens features the new updated "6-bit" coding, that allows the M digital camera to optically read this information and then identify the lens being mounted. Optionally the M camera can then apply a software based "last stage" vignetting adjustment (for images captured in RAW, the lens mounted is simply recorded, with no changes made). Apr 20, 2011
Read more.
May 10, 2011

Features
• Compact wide-angle lens with 2 aspherical elements provide excellent optical performance
• Includes "6-bit code" which allows digital M-series cameras to identify which lens is being used, and also to store this information in image metadata
Item Includes
• Leica 21mm f/1.4 Summilux-M Aspherical Manual Focus Lens
• Lens Caps
• Leather Lens Case
• Lens Hood
• 3 Year USA Passport Warranty
Reviews
Leica 21mm 1.4 summilux aspherical, February 5, 2010
By P. Halperin (NY, USA)
I have been working with this lens for only 1 week on an M9. It is without doubt one of the finest I have ever used. At f1.4, central image is extremely well detailed even at the minimum focusing distance of 0.7 meters, thanks to the floating elements. The corners are very slightly softer at 1.4 but more than able to render sufficient detail, and of course there is noticeable vignetting wide open. Stopping down yields fantastically crisp, 3 dimensional quality with beautiful tonality, corners to corners. It has a "just right" degree of contrast, not too much to clip highlights or shadows. Form f4 down, this lens is probably the finest quality 21mm lens made for the 35mm camera. At 1.4-2, it's the only 21mm of it's kind. the ability to achieve selective separation of subject and foreground and background yields a totally unique image at 21mm. Ridiculously expensive, and that good a lens. Lastly, for an external finder, I highly recommend the Zeiss 21mm finder which is gorgeous to look through.
M Mount Adapters
The Leica M mount was introduced in 1954 at the same time as the Leica M3. It's been the mount of choice on every Leica M series thru the present day Leica M7 film camera and Leica M9 digital camera
and Lenses.
The M Mount was also the mount used for Minolta's CLE rangefinder, on the Konica Hexar RF, on the later versions of the Voigtlander Bessa family
and Lenses, the mount for the Rollei 35RF, also quite recently on the newest Zeiss Ikon
Rangefinder and Lenses..
Benefits of Lens adapters is versatility, and saving money with the continued use of the preferred lenses you already own.
Drawbacks of lens adapters is the inconvenience, no electronic connection between the adapted lens and your camera body
A couple of factors are necessary for a lens adapter to work properly. First, the camera body "lens registration" space or the expanse between the mount of the lens to the sensor or film surface. Two, the "throat size" of the mount or the mount diameter. An adapter flanked by the body of the camera and a lens from different brands, this registration distance of the adapted lens must be larger than the registration distance on the body; plus the lenses throat-size must be less than the throat size on the body mount.
M lenses can be adapted to Canon EOS, Nikon, Micro Four
Thirds, and Sony Nex Cameras.