Leica has announced the Elmarit-S 30mm f/2.8 ASPH wide-angle lens for its S-system medium format DSLR. The lens, which offers a 24mm equivalent field of view, can focus down to 0.5m.
The lens will be available beginning December 2011. Prior to this announcement, Leica’s widest S lens was the 35mm f2.5 ASPH.
More info : http://us.leica-camera.com/home/
And from Carl Zeiss comes the just announced Distagon T* 25mm f2.0 wide-angle lens in ZE (Canon) and ZF.2 (Nikon) versions. The manual focus lens includes a CPU to provide aperture information to the camera, allowing the use of automatic exposure modes and the recording of EXIF data.
More info : http://lenses.zeiss.com/photo/en_DE/home.html