Its been a quest of mine to find a decent wide-angle for my Leica M9. After trying various options I found a mint S/H Zeiss 21mm f2.8 biogon lens over the weekend and decided to give that a try.
I've had mixed fortunes with Zeiss lenses. Some have been good like the 28mm f2.8 Biogon and some have been very disappointing such as the Nikon Mount 18mm that I bought.
No such problems with the 21mm. This is an excellent lens. Extremely sharp, and once stopped down sharp across the whole frame also. The edges are a bit soft at f2.8 but from f5.6 onwards the edges improve significantly.
There is a problem with regard to the Leica M9 and wide-angle lenses involving a magenta cast that appears down one side of the image. This has been addressed by Leica in a recent firmware update. There is still a slight cast on the raw files, but I put together a preset in Photoshops raw converter to remove both that and the vignetting that wide angle lenses have. Consequently the files from the lens are fine.
21mm is not super wide, and is obviously a good deal less than I was getting from the 15mm Voigtlander I was using before. However the problems that lens was causing with the magenta cast tended to render it less useful as I was having to crop out the problem areas. It was often impossible to remove the cast without removing all sorts of other things, so the actual usefulness of the lens was compromised.
I am extremely pleased with the Zeiss, finally I seem to have found a wide-angle that performs as well as less extreme lenses. Zeiss 21mm lenses generally have a good reputation and this one is certainly everything I could have hoped for.
Images - D & A