This is an interesting patent application (2024-090416) with some curious lens designs. What struck me mostly was that there seemed to be odd consistencies that you don't usually see in Canon patent application embodiments such as most of the lenses all the exact same size (95.51mm in this case). That struck me as odd, as I am wondering if that was a design decision that required the lenses to be around 75mm in lens length (if mounted on an RF camera).

Also what was curious is the amount of stretching on the wide end was also very consistent with most of the lenses having the same 17.95 radius of the image circle (that's really what half image height means, just in case you were wondering).

Now the lenses appear to be too big for super-35, so for cinema S35 size, this doesn't seem to be the case – and about the only sensor size that would be relevant, would be .. APS-H, but I don't think we are going to see any RF-H lenses in this universe. So I assume these are all fairly small, compact lenses made for full-frame sensors that rely on significant digital correction.

Eagle-eyed readers may note that some of the lenses I left off “RF” – the primary reason for that is that any lens under 10mm in back focus distance, I naturally assume is too tight for an RF camera body. It could be that those lenses are made for RF cinema where there wouldn't be a mechanical shutter. Hence, there's a little more freedom to inset the rear of the lens closer to the sensor, but that would make the lenses incompatible with RF stills cameras, which sounds like an awkward situation to me. But it wouldn't be the first time Canon has done such a thing.

Canon RF 20-40mm F4 IS

WideMiddleTelephoto
Focal Length20.6028.4039.00  
F-Number4.104.104.10
Half Angle of View41.0634.6428.01
Image Height17.9519.6220.74
Lens Length95.5195.5195.51
Back Focus Distance12.6712.6712.67  

Canon RF 24-40mm F4 IS

WideMiddleTelephoto
Focal Length23.0029.2337.45
F-Number4.104.104.10
Half Angle of View37.9733.8728.98
Image Height17.9519.6220.75
Lens Length95.5195.5195.51
Back Focus Distance13.4121.8327.43

Canon RF 22-40mm F4 IS

WideMiddleTelephoto
Focal Length23.0029.2337.45
F-Number4.104.104.10
Half Angle of View37.9733.8728.98
Image Height17.9519.6220.75
Lens Length95.5195.5195.51
Back Focus Distance13.4121.8327.43

Canon RF 26-40mm F4.5-6.3

WideMiddleTelephoto
Focal Length26.0029.6140.00  
F-Number4.635.666.48  
Half Angle of View38.47 33.59 27.09  
Image Height18.6419.36  20.46  
Lens Length99.7199.7199.71
Back Focus Distance20.0023.4833.39  

Canon 22-40mm F4 IS

WideMiddleTelephoto
Focal Length22.59 29.55 38.60  
F-Number4.104.104.10
Half Angle of View38.47 33.59 28.25
Image Height17.95 19.62 20.75
Lens Length95.51 95.51 95.51 
Back Focus Distance8.00 8.00 8.00 

Canon 22-35mm F4 IS

WideMiddleTelephoto
Focal Length21.7528.28 36.54
F-Number4.104.104.10
Half Angle of View39.54 34.76 29.58
Image Height17.95 19.62 20.74
Lens Length95.51 95.51 95.51 
Back Focus Distance8.00 8.00 8.00 

Source: Japan Patent Application 2024-090416

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2 comments

  1. Seeing that all those lens formulae have (almost) the same size of about 95 to 99 mm the only one that seems interesting is the one with the widest zoom range.
    So the 20-40mm F4 IS. I am not sure if I would like or buy such a lens.
    But I am sure, Canon will decide for the one that sells the most, or -as we know - that patent will never become a product.
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  2. Budget f/4 zoom lenses would be interesting but they would also cause a lot of confusion.
    Even though dedicated cinema cameras lack any mechanical shutter, they do have an ND filter wheel which takes up about the same space.
    • 0

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