It looks like Sigma is continuing to work on wide angle lenses for full frame cameras. A recent patent application shows an optical formula for a 12mm f/2.8 Art series lens for full frame cameras.
Sigma 12mm f/2.8 Art Specifications:
- Focal length: 12.42mm
- F number: 2.93
- Angle of view: 120.49
- Image height: 21.63mm
- Lens length: 169.4mm
Sigma doesn’t have any fear of making lenses with similar focal lengths and speeds, so it wouldn’t surprise me to see this patent actually become a product in the near future.