Canon Patent Application: Mirrorless APS-C kit telephoto zoom

In this patent application, Canon is attempting to patent a mirrorless APS-C telephoto zoom.  With any telephoto, it's nearly impossible to tell what mount this could be made for, as either the EOS-M or the EOS-RF mount are very similar in back focus distances.  All these embodiments are for a 55-250mm F4-5.6 lens.  With Canon seemingly limiting the EOS-M to lenses that are 61mm in diameter, this seems very unlikely to be an EOS-M design.  Also, two of the embodiments are very close to the back focus distance of the RF mount (20mm). 

As with any patent applications, it's never a guarantee that this will end up in an actual product, but it's more insight into what Canon is researching.

Canon APS-C 55-250mm F4-5.6

focal length        56.50 135.00 245.00
F number             4.12   5.17   5.85
Half angle (°)      13.59   5.78   3.19
Image height        13.66  13.66  13.66
Lens total length  138.50 174.37 193.50
BF                  21.90  53.63  70.32

Focal length        55.03 135.00 245.00
F number             4.12   5.17   5.85
Half angle (°)      13.94   5.78   3.19
Image height        13.66  13.66  13.66
Lens total length  140.00 175.51 194.32
BF                  20.65  42.09  46.74

focal length        56.50 135.00 244.99
F Number             4.12   5.17   5.85
Half angle (°)      13.59   5.78   3.19
Image height        13.66  13.66  13.66
Total lens length  134.97 171.67 189.98
BF                  14.02  32.29  45.60

Japan Patent Application 2021-081660

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