Canon produced an EF 28-300mm f/3.5-5.6L IS USM during the DSLR days that was a favourite of a smaller niche of photographers. We have had questions thrown our way asking if Canon would bring a modern RF version of this lens to the line-up, which we couldn’t and still can’t answer with any level of confidence.
If you remember, the EF 28-300mm f/3.5-5.6L IS USM utilized the “push/pull” design of its much more popular EF 100-400mm f/4.5-5.6L IS USM sibling. This design and focal range was either loved or hated by Canon shooters.
Now we have Japan Patent JP 2023 – 104137A that gives us an optical formula for such an RF mount lens in the form of an RF 24-300mm f/2.8-5.6L IS USM. This would be a lens that would garner a fair bit of attention if it comes to be.
This patent shows optical formulas that begin at f/2.8 and at f/4. The length of the lens design is quite close in the two designs, but we’d imagine weight and diameter would differ more so than the length. Both lenses drop to f/4.5 around 85mm if we’re reading the patent correctly, but that extra stop of light at the wide end would probably be welcomed in such a lens.
We don’t know if this type of lens is coming, but we would definitely be interested if it ever did.
Japan Patent JP 2023 – 104137A Overview
To provide a zoom lens which is small in size as a whole and has high optical performance over the entire zoom range while having a high zoom ratio.
https://www.j-platpat.inpit.go.jp/c1800/PU/JP-2023-104137/ED581F0EEC73D77E4B752044356B9C2B1AB66AFCC785C4A49E5CDCE9FD3A31CB/11/en
Canon RF 24-300mm f/2.8-5.6L IS USM
- Zoom ratio: 11.77x
- Focal Distance: 24.72mm 84.99mm 291.00mm
- F-number: 2.91 4.53 5.91
- Half field angle (degree): 36.98° 14.28° 4.25°
- Image Height: 18.62mm 21.64mm 21.64mm
- Lens Length: 166.17mm 211.37mm 256.52mm
- Backfocus: 12.42mm 45.03mm 65.56mm
Canon RF 24-300mm f/4-5.6L IS USM
- Zoom ratio: 11.78x
- Focal distance: 24.71mm 83.56mm 291.00mm
- F-number: 4.12 4.53 5.91
- Half Field Angle (Degree): 37.35° 14.52° 4.25°
- Image Height: 18.86mm 21.64mm 21.63mm
- Lens Length: 169.01mm 210.96mm 253.37mm
- Backfocus: 12.30mm 44.71mm 64.54mm
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