Nikon filed a patent 2012-27450 in Japan for a 18mm f/1.8 and 20mm f/1.8 full frame lenses:
- Focal length: 18.4mm
 - Aperture: 1.84
 - Angle of view: 100.3deg
 - Lens design: 14 elements in 11 groups
 - 3 aspherical elements
 - 3 ED elements
 
- Focal length: 20.4mm
 - Aperture: 1.84
 - Angle of view: 94.7deg
 - Lens design: 12 elements in 9 groups
 - 3 aspherical elements
 - 4 ED elements
 
It is typical for Nikon to patent several slightly different versions of each lens.








