Canon Patent Application: Canon RF super ultra wides

These lenses stretch the boundaries of what is possible for Canon.  It wasn't that long ago that Canon could make a ultra wide lens that was good, and now it seems they turn them out regularly.

This would be a halo lens, in a similar vein to the Canon EF 11-24mm F4L.  Will and would Canon develop the widest ultra-wide zoom? The possibility is certainly there and Canon loves to show off what they can do with optics.

With that in mind, let's take a look at some of the exotic super ultra wides that Canon has dreamt up in this patent application. Of course, with any patent application, there is never any guarantee that Canon will develop it, however, a patent application indicates that they were actively researching it.  Also, all these designs are full frame lenses, however some would most likely not fit on the RF mount given the amount of ingress into the mount these designs are asking for.  Even the following three designs sit back pretty far into the mount, and I'm not sure that's entirely possible, as it's nearly 8.5mm ingress.

Canon RF 9-17mm F4.0

focal length        9.27   15.01   17.46  
F-number            4.12    4.12    4.12  
half view angle    66.80   55.25   51.10  
image height       21.64   21.64   21.64  
total lens length 137.08  131.94  133.25  
BF                 13.49   13.49   13.49 

Canon RF 10-17mm F4.0

focal length       10.00   15.00   17.46  
F-number            4.12    4.12    4.12  
half view angle    65.19   55.27   51.10  
image height       21.64   21.64   21.64  
total lens length 135.49  124.63  123.10  
BF                 14.19   21.45   25.02 

Canon RF 9-17mm F4.0

Focus distance      9.27   15.01   17.46  
F number            4.12    4.12    4.12  
Half field angle   66.80   55.24   51.10  
Image height       21.64   21.64   21.64  
total lens length 137.95  129.32  129.39  
BF                 13.49   13.49   13.49

The following two designs are not suitable for the Canon RF mount, which has a back focus distance of 22mm.  

9-24mm F4.0

focal length        9.01   18.07   24.00  
F-number            4.12    4.12    4.12  
half view angle    67.40   50.13   42.04  
image height       21.64   21.64   21.64  
total lens length 146.16  138.36  143.68  
BF                 11.45   11.45   11.45  

8-16mm F4.0

focal length        8.00   14.67   16.00  
F-number            4.12    4.12    4.12  
half view angle    69.70   55.87   53.52  
image height       21.64   21.64   21.64  
total lens length 132.89  126.29  127.00  
BF                 10.00   10.00   10.00  

Japan Patent Application 2021-056320