Canon Patent Application: Some Bizarre Full Frame Compact Camera Lenses

This patent application illustrates some pretty crazy lenses, with almost impossible back focus distances.  On a Canon EF lens the back focus (BF) is usually around 44mm, on the EOS R system, the back focus distance is usually around 18mm.  However, these are between 2 and 0mm.  Yes, that is ZERO.  That means the actual back element is directly mounted or connected to the sensor.  Pretty wild.

I suspect such designs would work great on compact cameras where the lens may be very very close to the sensor.   These are also all full frame lenses, so perhaps a compact full frame camera?

Canon Full Frame 50mm F1.2

focal length         51.50  
F number              1.24  
Half angle of view   22.79  
Image height         21.64  
Total lens length    78.83  
BF                    0.50  

Canon Full Frame 50mm F1.6

Focal length         49.17  
F-number              1.65  
Half angle of view   23.75  
Image height         21.64  
Total lens length    72.35  
BF                    2.35

Canon Full Frame 50mm F1.2

focal length         51.50  
F number              1.24  
Half angle of view   22.79  
Image height         21.64  
Lens total length    78.00  
BF                    1.00 

Canon Full Frame 35mm F1.4

focal length         36.00  
F number              1.45  
Half angle of view   31.00  
Image height         21.64  
Total lens length   106.48  
BF                    0.00 

Japan Patent Application 2020-118846

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