Nikon patent Large aperture super-wide angle lenses made for Full Frame camera (FX format), read more details below
Self-interpretation and summary, Patent Document (translated by google)
- 2012-27450, Patent Publication No. 27451
- 2012.2.9 Release Date
- 2010.6.23 filing date
- Example 1
- 18.4mm focal length
- Fno 1.84
- 100.3deg angle.
- 14 pieces in 11 groups, the configuration
- Three three aspherical surface
- ED glass three
- Example 2
- 20.4mm focal length
- Fno 1.84
- 94.7deg angle.
- 12 pieces in 9 groups configuration
- Three three aspherical surface
- 4 ED glass sheet
- Retrofocus
- Focusing
- (18mm F1.8) is an example of inner focus
- (20mm F1.8) is a second embodiment of Inner Focus
- (18mm F1.8) is a third embodiment of rear focus
- (20mm F1.8) is a fourth embodiment of Inner Focus
- (20mm F1.8) is feeding the entire fifth embodiment
- Glass mold having an aspherical surface
- (Neither compensation nor a lack of compensation in excess) to adequately compensate for the sagittal coma flare and curvature of field
- Part of the second lens group can be used as camera shake correction
src – egami
