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In this patent application (2023-130885), Canon lists quite a few primes with a significant ingress, but also more notably a smaller image circle than what would normally be used for APS-C. For Canon APS-C, that’s 13.66mm, whereas all these lenses have 12.50mm. Super-35 just in case anyone is thinking that is around 14.2mm so they are not for that application either. This means that to fill the entire APS-C frame, the image would have been stretched to fill the frame, thus leading to a loss of resolution. However, the usual benefits are a smaller lens and also cheaper costs to manufacture the lens.
Usually, I would ignore this patent application out of principle, but here we are. To be fair, these are nice, fairly small ultra-wide APS-C lenses, so I’d buy them in a heartbeat and ignore everything that I just wrote. Economics and practicality do win out occasionally.
When reading these particulars, take into account that the lens length is to the sensor plane, so that includes the 20mm flange distance of the RF mount (as an example), so the physical lens length is 20mm shorter.
These lenses do have a short back focus distance, but it’s still in the realm of possibility.
I’m of the mindset that with focal lengths from 9mm to 30mm, Canon should simply make them all.
Canon APS-C 13mm F2.0
Focal length 13.40
F number 2.06
Half angle of view (°) 43.01
Image height 12.50
Lens Total length 77.83
Back focus 12.43
Canon APS-C 11mm F2.0
Focal length 11.30
F number 2.06
Half angle of view (°) 47.89
Image height 12.50
Lens total length 77.85
Back focus 12.44
Canon APS-C 22mm F2.0
Focal length 22.00
F number 2.06
Half angle of view (°) 29.60
Image height 12.50
Lens total length 72.85
Back focus 12.44
Canon APS-C 30mm F2.0
Focal length 30.52
F number 2.06
Half angle of view (°) 22.27
Image height 12.50
Lens total length 75.88
Back focus 14.49
Canon APS-C 9mm F2.0
Focal length 9.00
F number 2.06
Half angle of view (°) 54.25
Image height 12.50
Lens total length 79.30
Back focus 12.43
As with all patent applications, this application may not lead to an actual patent or actual products – but it does allow us to see what Canon was researching and thought relevant enough to attempt to patent it.
Source: Japan Patent Application 2023-130885
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