Close Menu

    Patent: 400mm f/2.8 DO and 300 f/2.8 DO

    By Updated:33 Comments1 Min Read Canon Patents
    patent40028do 728x462 - Patent: 400mm f/2.8 DO and 300 f/2.8 DO

    The diffractive optics related patents continue to appear from Canon. This time we get a patent that covers both a 300mm f/2.8 DO and a 400mm f/2.8 DO.

    We think a slew of diffractive optics super telephotos are on the way for the RF mount and these two optical formulas may find their way to the RF mount in 2020. Perhaps alongside an EOS R version of the EOS-1D X Mark II.

    As Canon News points out, the back focus on a super telephoto lens is quite large, so these could easily be RF mount lenses.

    Japan Patent Application 2018-189878

    Focal distance: 392.58
    F number:2.91
    A half field angle: 3.15
    Image height: 21.64
    Length of the lens: 363.53
    BF: 59.15

    Focal distance: 293.40
    F number: 2.91
    a half field angle: 4.22
    Image height: 21.64
    length of the lens: 274.00
    BF: 59.35

    Some of our articles may include affiliate links. If you purchase through these links, we may earn an affiliate commission at no extra cost to you.

    Go to discussion...

    Share.

    Related Posts

    33 comments

    1. Both lenses will be welcome in my photoequipment locker. I hope the optical quality will be on par with the existing 2.8 400/300mm lenses. Ad maybe 2 pounds lighter. (y)
    5. These lenses do not appear to be any shorter than the current 300/2.8 or 400/2.8. The 400/4 DO is more than a hundred mm shorter than the 363 length of the patent. So where is the benefit of DO in these patents?
    6. It would be unfortunate if they were restricted to the R range. If Canon continue with DSLRs, then it would seem sensible to make large telephotos compatible with both D and R bodies.
    7. It would be unfortunate if they were restricted to the R range. If Canon continue with DSLRs, then it would seem sensible to make large telephotos compatible with both D and R bodies.

      By and large the EF mount has all the big whites. Also it would be likely camera development will be in the R mount. Yes they will sell EF mount cameras for a bit more but I see the RF mount is where the new sensors and developments will be revealed.
    11. Very odd. The 400mm lens in the patent is 2 centimeters *longer* than the current and excellent 400mm f/2.8.

      Why this would be put out is a bit of a mystery.
      because the back focus of the 400 2.8 in EF form is longer, guess they can not get that any shorter for the R. so has to be added on to the lens
    12. Both lenses will be welcome in my photoequipment locker. I hope the optical quality will be on par with the existing 2.8 400/300mm lenses. Ad maybe 2 pounds lighter. (y)
      version 3 of the 400 2.8 is 2 pound lighter than version 2. knock anther 2 pound off you have nothing left
    13. Remember patents don't equal products!

      I don't think a 400mm f/2.8DO is a realistic release considering the new version 3 400 2.8 has just been launched. A 300 2.8? Maybe.

      If Canon come out with a new pro mirrorless camera for sports/wildlife you can almost guarantee there won't be any more big white EF lenses. Canon want to push people to switch, and releasing new lenses on the old format isn't going to help that.
    14. Very odd. The 400mm lens in the patent is 2 centimeters *longer* than the current and excellent 400mm f/2.8.

      Why this would be put out is a bit of a mystery.
      Same mistake as often:

      The "Length of the lens: 363.53 mm" in the patent is the length of the optical formula up to the image plane on the sensor.
      So you'll have to subtract the flange distance of the camera system (44 mm @ EF, 20 mm @ RF, if I remember correctly).

      This would lead to a mechanical length of the lens (barrel) of about 320 mm if its EF mount.
      And then it is just about 2 cm SHORTER than the existing EF 400mm f/2.8L IS III USM (343 mm).
      If it was RF mount then the mechanical size would be about the same as the existing EF lens.

      A little bit disappointing IMO as I thought DO would help to reduce length more than that.
    15. "...the back focus on a super telephoto lens is quite large, so these could easily be RF mount lenses"

      After looking at the back of my lenses, particularly the position of the rear elements relative to the mount, I'm convinced that the same is true of most/all lenses over 85mm.
    16. The tragic would be to make 500 and 600 DO lenses and make them available only in R. The 300 2.8 cannot be significantly smaller and/or lighter. I mean they may make it but its weight and size are well within the tolerance levels of most if not all photographers. The 400 saw a huge weight decrease (making it only 700grams heavier than the 400DOII f/4) so this would mostly benefit from a length decrease.

      Now where are our EF 500 and EF 600 DO lenses? :)
    17. Now where are our EF 500 and EF 600 DO lenses? :)
      They've just made the new 400 and 600, they might update the rest as well, but are not going to make yet more versions any time soon, these might even be the last versions as the product cycle can be very long.

      After the optical formula has been decided they can move over to figure out how to reduce the weight even more I think this DO stuff is probably more expensive if we compare lenses at the exact same focal length and aperture, so that means even higher pricetag over the version III EF lenses. But it will take a fair few years as Nikon Z-mount super telephotos aren't even mentioned in their 3-year roadmap (but it is a possiblity that they come out earlier than Canon because they will skip updating their F-mount super teles altogether), the newest EF lenses will probably do more than fine for the time being.
    18. It would be unfortunate if they were restricted to the R range. If Canon continue with DSLRs, then it would seem sensible to make large telephotos compatible with both D and R bodies.

      Cant you see D = Dead?
    19. lens look very interesting but I wonder when/if Canon will be R series body that be able to track a subject (bird in flight, football player and shot at 12 FPS. I understand that this is not easy do on a mirrorless camera.

    Leave a comment

    Please log in to your forum account to comment