A few recent patents that have been resurfaced by the folks at Canon Rumors provide a very interesting insight, not only into just how Canon goes about designing its lenses but also asks the question of why it picks the ones it chooses to release.
The patents concern three optical formulas for cheap and cheerful RF full-frame f/2.8 prime lenses – namely a 15mm, 18mm and 19mm. The patents for these lenses show optical formulas that would be made up of fewer elements, which would be at the sacrifice of some image quality, but this would enable the lenses to be very light and compact.
