Patent: Various RF mount zoom lenses, including an APS-C RF mount design

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    rfzooms - Patent: Various RF mount zoom lenses, including an APS-C RF mount design

    Canon continues to work on new zoom lens ideas for the RF mount according to this JPO patent, I can only see one lens below that makes sense for a consumer product, and that's the Canon RF 24-70mm f/4 optical design.

    Now hidden in here is an optical formula for what looks to be an APS-C RF mount optical design. The Canon RF 15-70mm f/4-7.1 has an image height that differs significantly from the other 4 optical designs, suggesting it's for a smaller sensor. Please correct me if I'm wrong on that assumption.

    Canon RF 24-70mm f/4

    • Focal Length: 24.72-67.90mm
    • F-Number: 4.12
    • Half angle of view: 41.50 – 17.30°
    • Image height: 19.69-21.64mm
    • Overall lens length: 101.50-141.15mm
    • Backfocus: 12.50-24.86mm

    Canon RF 24-120 f/4-7.1

    • Focal Length: 24.72-116.40mm
    • F-Number: 4.04-7.31
    • Half angle of view: 41.80-10.30°
    • Image height: 19.90-21.64mm
    • Overall lens length: 109.01-159.02mm
    • Backfocus: 14.15-31.01mm

    Canon RF 24-100mm f/4-7.1

    • Focal Length: 24.72-101.85mm
    • F-Number: 4.29-7.31
    • Half angle of view: 41.80-11.80°
    • Image height: 19.90-21.64mm
    • Overall lens length: 107.52-158.03mm
    • Backfocus: 13.48-35.52mm

    Canon RF 28-80mm f/3.5-5.6

    • Focal Length: 27.72-82.45mm
    • F-Number: 3.53-5.88
    • Half angle of view: 38.53-14.70°
    • Image height: 19.69-21.64mm
    • Overall lens length: 101.50-142.50mm
    • Backfocus: 14.16-32.52mm

    Canon RF 15-70mm f/4-7.1

    • Focal Length: 15.45-67.90mm
    • F-Number: 3.93-7.31
    • Half angle of view: 42.40-11.37°
    • Image height: 12.56-13.65mm
    • Overall lens length: 71.26-113.36mm
    • Backfocus: 12.40-24.51mm
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    3. A RF 24-70 f4 lens might be a big seller, but there is already a good RF 24-105 f4L.
      The 15-70 f4-7.1 would be a very big seller if it was FF, but it's not so I assume it's for the super-35 format video cameras.

      My preference would be a RF 15(or 17)-70 L IS (FF) lens (of whatever f#) to use as a single very wide to slight telephoto lens with high IQ and DOF (but much less background blur) which would be ideal for walk-around landscape use.
    4. A standard zoom with IS for the C70 (APS-C) would be amazing! However this 15-70 seems to lack IS and too dark. The current 24-70 2.8 IS is not wide enough on APS-C and 15-35 2.8 IS does not have enough tele for run and gun.
    5. With the 15-70 they must be joking or just patenting nonsense that they never plan to produce just to confuse competitors and general public.
      Or... they clearly show to all of us that for APS-C they will nevermore make a real lens, only crippled ones.

      For EF-S they produced the very good 15-85 f/3.5-5.6 IS USM. It was one of the few "higher quality APS-C" lenses. Something like "EF-S L" lens.
      With several RF L lenses Canon wanted to show that the new mount allows to overtrump the EF version (like 15-35 instead of 16-35, 100-500 instead of 100-400).

      So if Canon was wanting to show commitment to RF APS-C then the hypothetical RF mount APS-C camera would have IBIS and then then IS could be dropped in favor of compactness for a not so long zoom. So then it would be logical to see a patent for an RF-S 15-85 f/4-4.5 USM or an RF-S 15-90 f/4-6.1 USM or something alike.
    6. Interesting that all of those seem to require distortion/vignetting correction at the wide end. I guess that’s the new normal for cheaper zooms, like f/7.1 aperture :confused:
    7. Note that none of these are true FF lenses on the wide end. They all appear to be of the slight crop variety as the 24-240 mm 4.0-6.3 and 24-105 mm 4.0-7.1. Doesn't look like L lenses to me.
      Edit: Wasn't quick enough :ROFLMAO:
    8. If that 15-70 lens is full frame, I want it, it could be an incredible travel lens. Alternatively, I will keep hoping the 24-70 F/4 comes out soon.


      I'm still hoping they never make an APS-C RF Mount camera. It just makes more sense to me to have two separate lines of cameras, one designed specifically to maximize image quality in a full frame camera, and another designed specifically to capitalize on the size advantage of APS-C cameras and lenses. I don't know why a crop sensor camera needs a mount as large as RF, and from a consumer perspective it makes more sense if all you need to ask about is "does this lens fit on my camera?" (I can't speak for you guys, but when I was a beginning photographer, I definitely didn't know the difference between APS-C and full frame, nor that different lenses were designed specifically for one or the other)
    9. A RF 24-70 f4 lens might be a big seller, but there is already a good RF 24-105 f4L.
      The 15-70 f4-7.1 would be a very big seller if it was FF, but it's not so I assume it's for the super-35 format video cameras.

      My preference would be a RF 15(or 17)-70 L IS (FF) lens (of whatever f#) to use as a single very wide to slight telephoto lens with high IQ and DOF (but much less background blur) which would be ideal for walk-around landscape use.
      +100000000000000
      These were more or less my thoughts a few times already back when it wasn't mentioned as a crop sensor lens.

      It's a shame. A 17-70 FF would be the perfect excursion lens.
    12. I would stay far, far away from that f/7.1. The ISO speeds you need to cope with that aperture are maybe doable on FF, but on APS-C? Nope.

      Landascape, iso 100.....

      Depends the user case.
    13. I would stay far, far away from that f/7.1. The ISO speeds you need to cope with that aperture are maybe doable on FF, but on APS-C? Nope.
      It is certainly not ideal. But the difference between FF and APS-C is just 1.36 stops. If it looks like trash on APS-C, it wouldn't be pretty on FF either. Price and weight will be major factors in determining who this lens is a good fit for.
    14. Image height for FF sensor should be 21.63mm, and most lenses on the list have an image height of 19.7/9-21.64

      Seems to me Canon is going to repeat the trick it did with the RF 24-240mm - for some combinations of focal length & aperture, the lens isn't going to cover the whole sensor (it would lack almost 10% at the corners), and image correction will be applied to hide this. I'm a bit disappointed to see this in the RF 24-70mm f/4 patent.

      I was wondering whether I should buy f/2.8 lenses when upgrading to R5, or settle on f/4. I'll wait for the reviews, but this seems to indicate f/4 is going to be too much of a compromise.
    15. This could be just me, I think this is more of an issue because I am not used to f/7.1 and I am not a fan of any f/7.1 lenses so far including the 100-500. I wish Canon did not go slower than f/6.3 but the reality is different.
    16. Image height for FF sensor should be 21.63mm, and most lenses on the list have an image height of 19.7/9-21.64

      Seems to me Canon is going to repeat the trick it did with the RF 24-240mm - for some combinations of focal length & aperture, the lens isn't going to cover the whole sensor (it would lack almost 10% at the corners), and image correction will be applied to hide this. I'm a bit disappointed to see this in the RF 24-70mm f/4 patent.

      I was wondering whether I should buy f/2.8 lenses when upgrading to R5, or settle on f/4. I'll wait for the reviews, but this seems to indicate f/4 is going to be too much of a compromise.
      You're right! :oops: I hadn't thought of that, and if it is the case (which seems possible) it would be a major disappointment. In fact, such shrinking of the image circle to not illuminate at all the corners means that those lenses would turn the FF sensor into a "crop sensor" and they sure don't like to advertise that anywhere! That's the reason that I haven't considered buying the RF 24-240 lens and have been hoping for a new 24(or less)-200(or less)mm f4(or higher) L version (emphasis on the "L")!
    17. If that 15-70 lens is full frame, I want it, it could be an incredible travel lens. Alternatively, I will keep hoping the 24-70 F/4 comes out soon.


      I'm still hoping they never make an APS-C RF Mount camera. It just makes more sense to me to have two separate lines of cameras, one designed specifically to maximize image quality in a full frame camera, and another designed specifically to capitalize on the size advantage of APS-C cameras and lenses. I don't know why a crop sensor camera needs a mount as large as RF, and from a consumer perspective it makes more sense if all you need to ask about is "does this lens fit on my camera?" (I can't speak for you guys, but when I was a beginning photographer, I definitely didn't know the difference between APS-C and full frame, nor that different lenses were designed specifically for one or the other)

      APSC cameras make sense of selling products for those who have limited budget. In the DSLR world, a lot of people started buying a crop camera wishing to upgrade to FF eventually. I remember a lot of people bought an APSC camera with a kit lens, then their next move was to get the 17-40 f/4 as a standard lens for the APSC and then when they bought a 6D they had a nice wide lens. So Canon could get their customers trapped easier.
      I wish they'll never make an APS-C RF mount camera either. I wish they make somehow reasonably "crippled" FF body for $400 and cheap lower quality ~f/9 zooms. So people can buy cheap cameras and then easily upgrade.
    19. No one should have to live with f/7.1. No one.
      Are you serious, or joking? How can you say f7.1 is bad without any mention of what the lens focal length is? A 700mm f7.1 would have almost a 100mm aperture - Would you call that a bad lens?

      I love having fast lenses, and big background blur. But not every lens I use has to be that way. In fact, my previous system (Olympus EM1 II) had a 12-100mm f4 IS pro lens that was superb as a light weight walk around & landscape lens. Because of the 2x crop factor, it would take photos equivalent to a very high quality FF 24-200mm f8 lens & FF sensor (but yes, with only 1/4 the sensor well depth as it's a smaller sensor). That lens was superb for landscape and misc. travel photography since it was so sharp with great DOF. And their 300mm f4 IS pro lens took photos equivalent to an extremely high quality FF 600mm f8 lens & FF sensor and it was absolutely spectacular! (I've posted many photos from both of those lenses previously on CanonRumors for all to see).

      Not every application needs big background blur or big apertures for dark venues. Some applications, like daytime landscape use, are ideal for smaller & lighter f7.1 use. And if you ever get a RF 100-500mm f4.5-7.1 lens and take pictures at 500mm f7.1 I think you will be stunned at how beautiful they can be!

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