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    Canon has patented an optical formula for an RF 200mm f/2L IS USM

    By 25 Comments Canon Patents 1 Min Read

    The Canon EF 200 f/1.8L USM and EF 200mm f/2L IS USM are classic lenses, and it looks like Canon has plans for an RF version. While this focal length and speed are a niche combination, anyone that has used one knows they're pretty great.

    This lens does not appear on our roadmap, but it's very likely that it's part of Canon's plans in the future.

    Canon RF 200mm f/2L IS USM

    • Focal Length: 195.00mm
    • F Value: 2.05
    • Half Angle of View: 6.33°
    • Image Height: 21.64mm
    • Lens Length: 184.49mm
    • Backfocus: 22.35mm

    You can check out JPO patent P2023099385 here.

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    25 comments

    2. How many actual RF lenses were traceable back to a patent?

      I haven't read this patent, but the patents I have read (I read Japanese) are never for the lens formulae in the patent. Instead the patent is basically for a "recipe" to make a lens, and the lenses shown are simply examples of what you could do with that recipe. The patent might be say for a lens "recipe" whereby group 1 is net concave, group 2 is convex, group 3 accomplishes internal focus, group 4 is for image stabilization, group 5 is convex, group 6 is concave, with additional specifics on the lens group designs. Then they show how you can use this recipe to make a nice lens, but the patent isn't "for" that lens.
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    3. How many actual RF lenses were traceable back to a patent?

      I haven't read this patent, but the patents I have read (I read Japanese) are never for the lens formulae in the patent. Instead the patent is basically for a "recipe" to make a lens, and the lenses shown are simply examples of what you could do with that recipe. The patent might be say for a lens "recipe" whereby group 1 is net concave, group 2 is convex, group 3 accomplishes internal focus, group 4 is for image stabilization, group 5 is convex, group 6 is concave, with additional specifics on the lens group designs. Then they show how you can use this recipe to make a nice lens, but the patent isn't "for" that lens.
      Canon has a lot of patents.
      Not all of them are surfaced by these outlets.
      Although asobinet is doing a pretty good job.
      I can assure you that Canon would never make a lens without a patent.
      It would immediately be copied and sold for less by other companies.
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    4. How many actual RF lenses were traceable back to a patent?

      I haven't read this patent, but the patents I have read (I read Japanese) are never for the lens formulae in the patent. Instead the patent is basically for a "recipe" to make a lens, and the lenses shown are simply examples of what you could do with that recipe. The patent might be say for a lens "recipe" whereby group 1 is net concave, group 2 is convex, group 3 accomplishes internal focus, group 4 is for image stabilization, group 5 is convex, group 6 is concave, with additional specifics on the lens group designs. Then they show how you can use this recipe to make a nice lens, but the patent isn't "for" that lens.
      Yes, the heart and enforceable portion of a patent is in the claims, not just a particular example or illustration utilizing one or more of the claims.
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    5. I can assure you that Canon would never make a lens without a patent.
      I never suggested that Canon would make a lens without a patent.

      Instead I'm saying that of the patents I've read, and I say this as a life-long engineer who's been fluent in Japanese 30 years, are NOT FOR LENSES. They are for RECIPES FOR LENSES.

      If the recipe is patented, no-one else can make a lens of that recipe without licensing from Canon.

      I mean, thank you for agreeing with me.

      But the way you put it makes it sound like you are correcting me.
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    6. How many actual RF lenses were traceable back to a patent?
      All of them.

      Here's a recent example, the patent including the RF 24/1.8 (though that was yet another post where CRguy and/or his source mistook the patent for RF-S). You can see the matching patent diagram and actual lens block diagrams here.

      I haven't read this patent, but the patents I have read (I read Japanese) are never for the lens formulae in the patent. Instead the patent is basically for a "recipe" to make a lens, and the lenses shown are simply examples of what you could do with that recipe.
      Yes, patents are for optical formulae. Nothing new here, that's always been the case. It leads to confusion for some, e.g. when people read a 'lens length' value and assume it means the length of the physical lens since they don't know it actually means the optical formula length (front surface to image plane).
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    7. I don't understand the point of a new RF version of this lens when it's already well covered with the EF version. Sure, it'll have the latest Image Stabiliser and control ring. But It's still an F2 like the current EF version. Size and RF integration aren't really top priority for users of a 200mm f2.0 lens. So I'm not seeing much benefit for quite and expensive side grade.
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    8. I don't understand the point of a new RF version of this lens when it's already well covered with the EF version. Sure, it'll have the latest Image Stabiliser and control ring. But It's still an F2 like the current EF version. Size and RF integration aren't really top priority for users of a 200mm f2.0 lens. So I'm not seeing much benefit for quite and expensive side grade.
      It's a 15-year-old lens that was already discontinued 2 years ago... So I guess one advantage of an RF lens is that you might be able to order one...

      There has been numerous optical advancements since then, support for new teleconverters, quicker aperture supporting higher framerates etc etc.
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    9. I don't understand the point of a new RF version of this lens when it's already well covered with the EF version. Sure, it'll have the latest Image Stabiliser and control ring. But It's still an F2 like the current EF version. Size and RF integration aren't really top priority for users of a 200mm f2.0 lens. So I'm not seeing much benefit for quite and expensive side grade.
      It will be a better lens in every aspect that can be used without an adapter. And there is no dearth of rich people. :-)
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    12. With the new 135 f/1.8, I think there is less of a chance this'll actually make it to manufacturing. I suspect the brunt of the market would prefer the shorter lens. That 135 is definitely remarkable, both for image quality and quickness of focus. In most portrait shooting situations, it's an easier focal length to manage.

      I'm all for Canon coming out with more options, but with them producing lenses from a small fraction of their patents, I'm not holding my breath.
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    13. It's a 15-year-old lens that was already discontinued 2 years ago... So I guess one advantage of an RF lens is that you might be able to order one...

      There has been numerous optical advancements since then, support for new teleconverters, quicker aperture supporting higher framerates etc etc.
      However...it'll be a tough sell for a new RF one, I can pickup a mint S/H EF one for only £3K
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    15. Oh my:D it will be too expensive for me, but I will never not want to have one again. I still haven’t tried anything else that gets me those shots. It’s magic..
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