Canon Patent Application: Underwater RF Super-35 CINI Lenses

In this patent application, Canon describes some very complex zoom lenses in the embodiments.  The actual patent application is for underwater photography.  It's an optical convertor that is attached to the front of the lens to compensate for the difference in refraction between saltwater and air.  The lenses of course are designed for use in air and when used underwater, the difference of refraction can cause aberrations. 

Looking at the above image, the optical converter is section ld and lf of the diagram.  The actual lens is the section (lm).  While the convertor is interesting and has a wide range of applications for underwater photography, I'm more curious about the lenses. 

The lenses are definitely cinema and super-35, as they have a 15.55mm image height which is larger than APS-C and less than full frame.  Another clue that it's for cinema purposes is the massive amount of optical elements in the lens design.  These aren't your garden variety APS-C cropped lenses here.

Keep in mind that this patent application would work regardless of the lens design but the inclusion of these complex cinema optical designs is curious.

Canon RF Cinema 13-90mm F2.8-4

focal length        13.15   38.61   93.99
F number              2.8    2.9     4.12
Half angle of view  49.79   21.94    9.39
Image height        15.55   15.55   15.55
Lens total length  423.63  423.63  423.63
BF                  20.64   20.64   20.64

Canon RF Cinema 14-100mm F2.8-3.6

focus Distance      14.06   41.36   99.33
F number             2.80    2.80    3.61
Half angle          47.87   20.61    8.90
Image height        15.55   15.55   15.55
Lens total length  390.30  390.32  390.41
BF                  39.99   40.00   40.09

Canon RF Cinema 15-105mm F2.8-4.0

focal length        14.98   44.10  105.46
F number             2.80    2.83    3.92
Half angle of view  46.07   19.42    8.39
Image High          15.55   15.55   15.55
Lens total length  402.64  402.62  402.27
BF                  17.81   17.94   17.60

Canon RF Cinema 12-90mm F2.8-4.0

focal distance      12.56   36.94   88.56
F number             2.80    2.84    3.95
Half angle          51.08   22.83    9.96
Image height        15.55   15.55   15.55
Lens total length  420.28  420.29  420.16
BF                  18.78   18.89   18.76

Japan Patent Application 2022-024363

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