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    Canon RF 24-300mm f/2.8-5.6L IS USM optical formula patent published

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    patent24300 728x410 - Canon RF 24-300mm f/2.8-5.6L IS USM optical formula patent published

    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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    68 comments

    1. shocked its not a 7.1 aperture.... I really hope Canon lives up to the hype it's built around its ability to build new and unique lenses. We went into the RF mount expecting a lot of innovation, but to the same degree that we've been impressed, we've also been pretty disappointed. I still cant forgive that 100-500 L lens with that eye watering price point. lol
    2. I had the EF 28-300L for a while, the lens was good but not great, but also very convenient. IQ was on par with the EF 24-105L through the range but not as good as the EF 24-70/2.8L II + 70-300L, so I ended up selling the 28-300 (I had bought it used, kept it for two years, and sold it for more than I paid).

      If the IQ is similar to the RF 24-105/4 that is my primary lens, I’d consider buying an RF 24-300L.
    3. I still have the EF 28-300L which replaced my much-loved EF 35-350L. I tend to use the 100-400L rather more these days, but always miss the wide end. When the R1 arrives, I will move over to RF, with the 100-500L planned as my first RF lens, but I would be hugely drawn to a RF 24-300mm f/2.8-5.6L - loving the extra light at the wide end!
    5. I’m ALL in on this lens! For 10 days straight every year the 24-240 becomes my main lens for the biggest/longest race I shoot. There’s simply no replacement for a mega zoom during that event. As surprisingly good as the 24-240 has been, it’s still a major step backwards from L series performance - especially the handling of chromatic aberration and distortion.

      So if this comes out, I will be locked and loaded for it.
    7. I would also have interest in this one as an all rounder, but given the price tag for those "I Want" lenses, once again another cure for G.A.S. is coming.

      BTW, I do a massive amount of auto racing as well, but only sports cars, I.E. IMSA, Le Mans stuff. When I did Watkins Glen 6 hours this year, I shot about 3500 with my EF 400 f/2.8. The 2.8 allowed me to shoot through catch fencing and not see it in the photos. I probably did 200-300 with my 100-400L mark II, and maybe 4000 or 5000 with the 70-200L Mark II. I did not have an exact purpose for that lens until I got it and found it's sweet spot. I shot nearly 10,000 track & field meet photos with it too. I used the 24-70 maybe 20 times. So far the 70-200 wins for racing.

      One other observation I could not find where to add, so it goes here. I might have seen 2-5 people with the R3. I saw a huge number of regular Joes like me with 1DX models. Probably hundreds to maybe even 1000 with the R6's I have, but mostly the R5. (Plus a mountain of 90D, 80D, 5D etc. I saw one guy everywhere I went with an 80D, attached to a 500mm with an extender on it. I asked him, are you shooting their nose hairs? If not Sony or nikon, pro or consumer stuff, the R5 ruled, I asked a few pros with the R5 and the 300mm f/2,8 why and heard the exact same answer, "crop". I said, 24 megapixels is good if you have the glass to get it right on the first shot. I do NOT have the time to go through the 12500 shots over 4 days at a race, or 5000 at a track meet, to sit and edit/crop them.
    8. I wonder what the max. magnification is on the 24-300 f2.8-5.6L? I hope it's a relatively high value, but we will see.
      This would be a definite purchase for me as my best "single lens & camera" option.
      I do wonder what the size & weight of it will be, and I hope it's not too heavy.
    10. I wonder what the max. magnification is on the 24-300 f2.8-5.6? I hope it's a relatively high value, but we will see.
      This would be a definite purchase for me as my best "single lens & camera" option.
      I do wonder what the size & weight of it will be, and I hope it's not too heavy.
      technically it will be lighter overall as you wont need to be carrying multiple lenses!!!! :)
    11. technically it will be lighter overall as you wont need to be carrying multiple lenses!!!! :)
      I'm not sure if it'll be lighter or not than both 24-70L and 70-300L together, but using one of these at a time will be easier to use than whatever the 24-300 weighs.
    15. How do we know these will be "L"?
      Inference based on the apertures in the patent. The RF 24-240mm lens is f/4-6.3 so a non-L 24-300mm would almost certainly be f/7.1 or even f/8 at the long end. Your implication that a patent does not directly indicate L vs non-L is correct.
    16. I still cant forgive that 100-500 L lens with that eye watering price point. lol
      It's a zoom thats substantially sharper than at least one of the top three black EF lenses (the 135/2). And you can buy it used for what you can probably sell it for used, so it's price is in effect zero unless you tend to be brutal on equipment.
    17. it’s still a major step backwards from L series performance - especially the handling of chromatic aberration and distortion.
      L lenses aren't always very high performance. The original EF 14/2.8, 50/1.0 and 35-350 weren't sharp. Or even the first generation of trinity zooms (20-35/2.8, 28-80/2.8-4 if I remember correctly, and 80-200/2.8). The old book "Canon Lens Work" I believe defined "L" lenses as simply being one with a ground aspherical, fluorite, or UD element. That rule has since disappeared with 3-4 non-L lenses in the 2010 (and maybe earlier) having such elements but not being L.
    18. I had the EF 28-300L for a while, the lens was good but not great, but also very convenient. IQ was on par with the EF 24-105L through the range but not as good as the EF 24-70/2.8L II + 70-300L, so I ended up selling the 28-300 (I had bought it used, kept it for two years, and sold it for more than I paid).

      If the IQ is similar to the RF 24-105/4 that is my primary lens, I’d consider buying an RF 24-300L.
      Hmmm, I shot with the EF 24-105/4 MkI and never was quite satisfied with the IQ. I'd use it a while then switch back to the 24-70 or the various 50's. I had eye problems throughout the MkII era so never tried it.

      The RF 24-105/4 was a huge improvement and I was really happy with it for 2-3 years. I have to say it's actually substantially worse than the 50/1.8, 100/2.8, 100-500, and possibly just better than the 16/2.8. I'm actually shooting the 50/1.8 as my main lens again. But, I think I am being pickier than I need to be. The 24-105/4 photos were always good enough for my needs, just not quite as nice as the other RF's.

      I actually assume the 24-300L will be a substantial step down from the 24-105, as quality usually suffers when you make the spec crazier and crazier.

      It's a lens that's utterly irreplaceable for some types of shooting, and IQ isn't even the most important thing as so many lenses are more than acceptable.

      But I can't get excited about the level of sharpness I'm kind of expecting.

      In fact one of my big hopes is for an improved 24-105/4. I'd pre-order one the microsecond I first saw it.
    19. I wonder what the max. magnification is on the 24-300 f2.8-5.6L? I hope it's a relatively high value, but we will see.
      This would be a definite purchase for me as my best "single lens & camera" option.
      I do wonder what the size & weight of it will be, and I hope it's not too heavy.
      If you want higher mag, you can try a 250D or 500D or other closeup lens. It would make the lens EXTREMELY macro at 300mm...

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