Leica 21mm F2.8 Elmarit & Asph. Leica 21mm Elmarit F2.8 Asph. The Leica 21mm F2.8 Summilux was developed as the succesor to the Schneider designed 21mm Super Angulon.  The lens has been produced in three versions since its inception in 1980.  The first two versions were identical except for a cosmetic change to the front ring altering filter size and hood type.  The current Asph. model is a stunning performer and is clearly the best of the 21mm lenses offered for the M system. The current Asph. model employs a 9 element design, of which 1 is Glass Moulded Aspherical, three incorporate High Refractive Index glass and two have glass with partially abnormal dispersion.  This high tech approach has yielded a design of stunning clarity that is free of abberations that are so typical with super wide angle lenses.  Vignetting and distortion are not problems with this lens.  The Perfect hood (rectangular to the dimensions of the 35mm frame) and excellent multicoatings make the problem of flare almost non existant.  The 21mm in the right hands can produce exciting compositions with proper foreground subjects.  Landscapes, Architectural and Photojournalism are all noteworthy applications for this focal length lens.  The 21mm is truly a Super Wide, where the 24mm is on the border of wide and super wide.  The lenses although seemingly close in range, are very different in practice.  A few rolls might be spent before you get the hang of it, but once you do you will capture images that others will only be left wondering on how you did it.   21mm F2.8 Elmarit 1980-1997 Type 1 & 2  non-Asph. SN#2,995,000-N/A Finish Black, Chrome Mount Rigid Lens Elements 8 in 6 Groups Filter Size 49mm First Version & 60mm Second Version Apertures F2.8-F16 Angle of View 92 Degrees Minimum Focus Distance 70cm Units Produced N/A Weight 290 Grams 1990-1994 Type 1 Asph.  SN# N/A Finish Black Mount Rigid Lens Elements 9 in 5 Groups - 2 Asph. Filter Size 46mm Apertures F1.4-F16 Angle of View 64 Degrees Minimum Focus Distance 70cm Units Produced 2000-4000 Weight 300 Grams 21mm F2.8 Elmarit Asph. 1997-Present Type 3 SN# 3,780,533-Present Finish Black, Chrome Mount Rigid Lens Elements 9 in 7 Groups, 1 Asph. Filter Size 55mm Apertures F2.8-F16 Angle of View 92 Degrees Minimum Focus Distance 70cm Units Produced N/A Weight 300 Grams