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    Patent: Canon RF 17-35mm f/4-5.6

    By Updated:70 Comments1 Min Read Canon Patents
    canonrf1735 728x462 - Patent: Canon RF 17-35mm f/4-5.6

    A new optical formula patent for a wide angle RF mount zoom has appeared. This one shows the formula for a couple of Canon RF 17-35mm f/4-5.6 designs.

    The lenses in the two embodiments aren't all that much smaller than an EF counterpart, and it looks like zooming is slightly external.

    Canon RF 17-35mm f/4-5.6

    • Focal length: 17.50mm 27.00mm 33.95mm
    • F-number: 4.00 5.03 5.80
    • Half field angle: 51.03° 38.71° 32.51°
    • Image height: 21.64mm 21.64mm 21.64mm
    • Lens total length: 121.00mm 118.39mm 121.18mm
    • BF: 20.00mm 30.99mm 38.92mm

    Canon RF 17-35mm f/4-5.6

    • Focal length: 17.50mm 27.00mm 33.95mm
    • F-number: 3.94 4.92 5.69
    • Half angle of view: 51.03° 38.71° 32.51°
    • Image height: 21.64mm 21.64mm 21.64mm
    • Total lens length: 122.00mm 119.11mm 121.87mm
    • BF: 20.00mm 31.62mm 40.07mm

    Once all of the fast zooms ship this year, I think it's safe to assume we're going to see f/4 variants soon after.

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    70 comments

    2. Almost, but not quite, a standard lens for an APS-C RF body.

      I think what Canon will do with APS-C on RF (if they even bother) is to produce lenses that are nominally full-frame lenses (so will work on all R bodies) but optimized for APS-C usage (ie not the best in the corners at FF - but with in-camera corrections this won't necessarily be such a problem.)
    3. Almost, but not quite, a standard lens for an APS-C RF body.

      I think what Canon will do with APS-C on RF (if they even bother) is to produce lenses that are nominally full-frame lenses (so will work on all R bodies) but optimized for APS-C usage (ie not the best in the corners at FF - but with in-camera corrections this won't necessarily be such a problem.)

      I really doubt they'd do this.

      Canon could take then 18-55 EF-M design and port it over to the RF mount in literally a new york minute, if they ever decided to make a consumer APS-C lens for the RF mount.

      The way the market is dying off at the low end I really doubt you'll see Canon go into the APS-C market at all with the RF mount.
    4. I really doubt they'd do this.
      ...
      Me, too.

      If I was Canon going into R APS-C I'd make a real APS-C kit lens. That'll be smaller than this patent as you wouldn't need that image circle.

      I've just posted a thread about Canon Germany's summer cashback. When you take a look at the last 3 or 4 cashback promotions here in Ger they focus on FF and high perf lenses.
      This looks to me as they quit thinking about the APS-C (DSLR) consumer market or those products are so much striped down in profit margin that there is no more place for promotions. And I don't think the later but the former.
    5. Arrgh, please no variable aperture. I would like to switch to an RF wide zoom but I'm probably going to stick with my EF on the adapter if I can't get 1. IS 2. constant aperture (f/2.8 would be super but f/4 acceptable) 3. 77mm filter thread (the forthcoming holy trinity lenses don't appear to be, according to the images published). Right now everything in my bag is 77mm so I have no step-up rings or duplicate filters and I'm loving it.
    6. Arrgh, please no variable aperture. I would like to switch to an RF wide zoom but I'm probably going to stick with my EF on the adapter if I can't get 1. IS 2. constant aperture (f/2.8 would be super but f/4 acceptable) 3. 77mm filter thread (the forthcoming holy trinity lenses don't appear to be, according to the images published). Right now everything in my bag is 77mm so I have no step-up rings or duplicate filters and I'm loving it.

      It's possible that, if APS-C is declining, Canon will fill out the variable-speed/STM line with an UWA, so the lines would be:

      1. 15-35/2.8 IS USM, 24-70/2.8 IS USM, 70-200/2.8 IS USM
      2. 15-35/4 IS USM, 24-70(-105)/4 IS USM, 70-200/4 IS USM
      3. 17-35/4-5.6 IS STM, 24-105/3.5-5.6 IS STM, 70-300/4.5-56 IS STM

      That STM variable UWA is one they haven't made yet to my knowledge, but they could make it to match the RP and have a full line of budget FF RF lenses for the folks stepping up from crop. That's just my speculation though.
    7. I would really really happy if they made this lens. The R-mount would be a great travel kit. 17-35 and the 24-240mm and maybe a prime lens too. It would be perfect for family trips. Good enough quality, that I could stop and take landscapes and Not be annoyed at the quality.
    8. it looks like zooming is slightly external.
      Not exactly. Movements of 2-3 mm are a common feature of pretty much all ultrawide zooms. If you look at them, you’ll see that it’s an inner barrel doing the moving, and it’s most deeply recessed in the middle of the focal range (which is exactly what you see in the lens length measurements from the patent). The outer barrel remains fixed, so all of the movement occurs behind the filter threads. That inner barrel is not weather sealed on otherwise sealed L-series UWA zooms, which is why those lenses have a statement in the instructions that a front filter is required to complete the weather/dust sealing.
    9. Not exactly. Movements of 2-3 mm are a common feature of pretty much all ultrawide zooms. If you look at them, you’ll see that it’s an inner barrel doing the moving, and it’s most deeply recessed in the middle of the focal range (which is exactly what you see in the lens length measurements from the patent). The outer barrel remains fixed, so all of the movement occurs behind the filter threads. That inner barrel is not weather sealed on otherwise sealed L-series UWA zooms, which is why those lenses have a statement in the instructions that a front filter is required to complete the weather/dust sealing.

      Tony Northrup told me I can skip the filter and fix it in Photoshop later.
    10. Tony Northrup told me I can skip the filter and fix it in Photoshop later.
      Sure sure. The healing brush tool is just the thing to clone out water drops on the sensor. But heck, those only show up if you stop down the lens…and TN says real photographers always shoot wide open.
    11. What would be the EF counterpart - the EF 17-40mm f/4L?

      I would expect the combination of shorter flange distance and f-stop slower on the wide side to allow for a smaller lens.
    12. What would be the EF counterpart - the EF 17-40mm f/4L?

      I would expect the combination of shorter flange distance and f-stop slower on the wide side to allow for a smaller lens.
      You might expect that, but in fact the 17-40L is actually smaller than these patented RF versions.

      Lots of people claim the RF mount allows substantially smaller lenses. So far, there’s no evidence to support that claim.
    13. You might expect that, but in fact the 17-40L is actually smaller than these patented RF versions.

      Lots of people claim the RF mount allows substantially smaller lenses. So far, there’s no evidence to support that claim.

      Which makes me wonder...

      1. Are the lenses larger because Canon had to put more glass (than shorter flange distance would save) in to improve IQ?

      2. If the shorter flange doesn't help to make smaller (or better) lenses, why did Canon change it in the first place?
    14. Which makes me wonder...

      1. Are the lenses larger because Canon had to put more glass (than shorter flange distance would save) in to improve IQ?

      2. If the shorter flange doesn't help to make smaller (or better) lenses, why did Canon change it in the first place?

      It does help to make better lenses. Just look at the RF 28-70 F2.0 or a new RF 85 F1.2. These are unique and/or amazing lenses.
    15. Which makes me wonder...

      1. Are the lenses larger because Canon had to put more glass (than shorter flange distance would save) in to improve IQ?

      2. If the shorter flange doesn't help to make smaller (or better) lenses, why did Canon change it in the first place?
      Maybe the RF lenses are designed to minimize vignetting by controlling the incidence angle of light on the sensor.
    18. Which makes me wonder...

      1. Are the lenses larger because Canon had to put more glass (than shorter flange distance would save) in to improve IQ?

      2. If the shorter flange doesn't help to make smaller (or better) lenses, why did Canon change it in the first place?
      I could see (1) for an L-series lens, but with a variable aperture it’s unlikely this would be an L.

      For (2), the lack of a mirror allows the body to be shallower (although it’s not a requirement, obviously). A shallower body requires either a new mount design to accommodate the shorter distance between sensor and mount, or a “snout mount“ like Sigma used.

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