svg+xml;base64,PHN2ZyB2aWV3Qm94PScwIDAgNzI4IDEwMjQnIHhtbG5zPSdodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2Zyc+PC9zdmc+ - Patent: Canon RF APS-C pancake prime lens optical formulas

    Patent: Canon RF APS-C pancake prime lens optical formulas

    By Updated:60 Comments1 Min Read Canon Patents

    It looks like Canon will be bringing one or more RF-S prime lenses for the Canon EOS R7 and Canon EOS R10. One of the most requested RF-S lenses is unsurprisingly a pancake lens. Keith at Northlight Images uncovered a patent at the USPTO with what looks to be RF-S pancake optical formulas.

    None of these

    Canon RF-S 14mm f/2.8

    • Focal Length: 14.28mm
    • F-Number: 2.90
    • Half Angle of View: 51.88°
    • Image Height: 18.20mm
    • Total Lens Length: 57.50mm (image sensor to front element)
    • Backfocus: 10.97mm

    Canon RF-S 16mm f/2.8

    • Focal Length: 16.48mm
    • F-Number: 2.90
    • Half Angle of View: 47.84°
    • Image Height: 18.20mm
    • Total Lens Length: 63.19mm (image sensor to front element)
    • Backfocus: 12.54mm

    Canon RF-S 10mm f/2.8

    • Focal Length: 18.20mm
    • F-Number: 2.90
    • Half Angle of View: 45.00°
    • Image Height: 18.20mm
    • Total Lens Length: 63.45mm (image sensor to front element)
    • Backfocus: 12.94mm

    Canon RF-S 20mm f/2.8

    • Focal Length: 20.10mm
    • F-Number: 2.90
    • Half Angle of View: 48.31°
    • Image Height: 18.20mm
    • Total Lens Length: 63.99mm (image sensor to front element)
    • Backfocus: 11.16mm

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    2. A RF-S 10mm f/2.8 prime would be a super nice budget option for a lot of vloggers/etc. Equivalent to the RF 16mm F/2.8 but an even smaller and more compact option for APS-C. The RF 16mm is already really nice and small for full frame cameras, so I can imagine it would make sense for Canon to fill that role for their crop camera consumers.
    4. Well, the full frame 16/2.8 is already pretty small, and I don't think it would be hard to pull the 22 over from the M series, with minimal alteration. But the 14 would make sense. Along with a 20 or 22 mm pancake.
    6. That's not APS-C. Closest would be Super35 or (gasp) APS-H.
      The specs state "RF-S" so they must be for APS-C models.

      Maybe a misprint, but perhaps Canon has deliberately elected to have a larger than normal image circle with these wide-angle optics, in order to minimise vignetting and softness in the corners?

      Or am I being daft?
    8. Maybe bigger image circle for ibis movement?
      That would be my guess as well: make the lens cheap, use IBIS or EIS to make it better. This is why I preordered the R7 instead of the R10 :)
    9. "Unsurprisingly" a pancake lens? I find that, generally, the smaller the lens the hard the camera is to handle. Pancake primes are the worst as there's literally nothing to hold onto with your left hand. Why do people want these things? I thought it was only about price, not desirability.
    10. The specs state "RF-S" so they must be for APS-C models.

      Maybe a misprint, but perhaps Canon has deliberately elected to have a larger than normal image circle with these wide-angle optics, in order to minimise vignetting and softness in the corners?

      Or am I being daft?
      What 'specs'? If it's not in the patent, it's not a spec, it's a guess by Keith, CRguy or someone else.

      But a larger image circle for IBIS makes sense.
    11. What 'specs'? If it's not in the patent, it's not a spec, it's a guess by Keith, CRguy or someone else.

      But a larger image circle for IBIS makes sense.
      As you point out, the patent application makes no mention of "APS-C" or "RF-S".

      The "specs" are, as you say, an informed guess - by a highly experienced commentator, Keith Cooper of Northlight.

      I'd be extremely surprised if his guess was wrong.

      If the larger image circle was purely to accommodate IBIS, I would have expected Canon to design *all* of its RF-S lenses to have this image circle, not just the pancakes under examination here.

      I think it's more likely that the larger image circle has been chosen to minimise corner softness and vignetting, both of which are a bigger problem with wide-angle pancakes than with longer focal lengths.

      But like Keith, I'm only guessing ;)
    12. That's not APS-C. Closest would be Super35 or (gasp) APS-H.
      Makes me wonder if the lenses couldn't be dual-purpose - APS-C and Super-35. Not a huge size difference there. I doubt they'll go for the 1.3X again. The purpose of that format no longer really exists.
    13. Why do people want these things? I thought it was only about price, not desirability.
      Presumably to reduce size and weight when travelling, hiking or mountaineering.

      A pancake takes up next to no room, and can even be carried in a pocket, to be available at all times.
    14. A RF-S 10mm f/2.8 prime would be a super nice budget option for a lot of vloggers/etc.
      The headline on that lens/patent is wrong. It is an 18mm as it says in text below:
      • Focal Length: 18.20mm
      Sorry :-/
    15. Presumably to reduce size and weight when travelling, hiking or mountaineering.

      A pancake takes up next to no room, and can even be carried in a pocket, to be available at all times.
      Exactly. The M6 with M22mm fits in my coat or cargo pants pocket.

      When going to an event where my primary lens was the 70-200/2.8, it was great to be able to drop the EF 40/2.8 into my pocket and swap on a normal focal length lens as needed (I typically carry with a BR strap attached to the lens foot, so the 70-200 could simply dangle from that as I shot with the 40 mm pancake) – it was a great, portable solution.

      That’s not really an option with my R3, because having to carry both the adapter and the pancake lens defeats the purpose. I would definitely like a normal or wide (not ultrawide) pancake prime for RF full frame.
    16. "Unsurprisingly" a pancake lens? I find that, generally, the smaller the lens the hard the camera is to handle. Pancake primes are the worst as there's literally nothing to hold onto with your left hand. Why do people want these things? I thought it was only about price, not desirability.
      For very short ( pancake) lenses, you craddle the camera with your left hand
    17. Exactly. The M6 with M22mm fits in my coat or cargo pants pocket.

      When going to an event where my primary lens was the 70-200/2.8, it was great to be able to drop the EF 40/2.8 into my pocket and swap on a normal focal length lens as needed (I typically carry with a BR strap attached to the lens foot, so the 70-200 could simply dangle from that as I shot with the 40 mm pancake) – it was a great, portable solution.

      That’s not really an option with my R3, because having to carry both the adapter and the pancake lens defeats the purpose. I would definitely like a normal or wide (not ultrawide) pancake prime for RF full frame.
      Okay, but how do you hold the camera? I usually hold the weight of the camera in my left hand by putting my left hand under the CG of the camera-lens combination, which is always somewhere along the length of the lens. With a small prime, the CG is in the body and there's no place for me to put my left hand. That leads to trying to hold the body with my left hand on the left edge of the body where there's no grip.
    19. "Unsurprisingly" a pancake lens? I find that, generally, the smaller the lens the hard the camera is to handle. Pancake primes are the worst as there's literally nothing to hold onto with your left hand. Why do people want these things? I thought it was only about price, not desirability.
      You know, you don’t have to use a pancake lens..?

      Slap that massive 50mm 1.2 on it if you want.

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