One of the niche, yet loved lenses from the EF mount era is going to get the RF treatment with an all new design in 2024. That lens will be the Canon RF 400mm f/4 DO IS USM.

Canon has made three “DO” branded lenses, all for the EF mount. The first was the original EF 400mm f/4 DO IS USM in 2001, and in 2004 they launched the more affordable zoom offering, the EF 70-300mm f/4.5-5.6 DO IS USM. In 2014, Canon released the EF 400mm f/4 DO IS USM II, which improved the contrast issues found in the first version. All of Canon's past EF DO branded lenses have been discontinued.

We have been told that Canon will once again bring a DO branded lens to the RF mount, in the form of an RF 400mm f/4 DO IS USM. The lens is coming some time in 2024, and will continue to improve on Canon's DO lens designs.

Many years ago, Canon did show off an EF 600mm f/4 DO IS USM prototype that never came to market, but we have received some hints that Canon does have a 600mm DO lens in the pipeline, but not before the RF 400mm f/4 DO IS USM is announced.

Go to discussion...

53 comments

  1. Interesting. I wonder if the direct replacement White primes will all be DO lenses going forwards. It makes sense if this lens is built as a RF 400mm f2.8 DO and then releasing a 100-400mm f2.8 L. It literally could be a smallest adn lightest 400mm f2.8 ever constructed.
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  2. I am exited to see what has happened in 10 years development of DO/Fresnel lenses.
    Nikon showed some things that made some of us on the Canon site jealous, indeed.
    New materials and new production methods should become visible in IQ.
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  3. I am exited to see what has happened in 10 years development of DO/Fresnel lenses.
    Nikon showed some things that made some of us on the Canon site jealous, indeed.
    New materials and new production methods should become visible in IQ.
    I have had two copies of the Canon 400mm f/4 DO II, and my Nikon 500mm f/5.6 did not have better IQ. But, the Nikon was much lighter and about half the price here. The DO/PF lenses all suffer performance against bright backgrounds because of the zero-order spectrum of the diffraction grating. But, you need the light behind you anyway. My RF100-500mm at 500mm outperformed the DO at 400mm, and a 400/4 has only 1 stop more photons/duck than a 400/5.6 or 500/7.1. With a 2x TC at 800/8 it will be only 1/3rd stop faster than the 200-800 at 800mm f/9. Let's see how good it is and the price and the price and weight.
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  4. Interesting. I wonder if the direct replacement White primes will all be DO lenses going forwards. It makes sense if this lens is built as a RF 400mm f2.8 DO and then releasing a 100-400mm f2.8 L. It literally could be a smallest adn lightest 400mm f2.8 ever constructed.
    If all big whites became DO, why would they bother putting it in the name? (The RF f/11 supertele primes have DO but it's not in their designation).

    The rumour is for an f/4, not f/2.8.
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  5. If all big whites became DO, why would they bother putting it in the name? (The RF f/11 supertele primes have DO but it's not in their designation).

    The rumour is for an f/4, not f/2.8.
    There is a patent for a 400mm f2.8 DO and a 600mm f4 DO. The 600 f4 DO was seen as a singular prototype at a show a few years back.
    Just because Canon have alrfeady made two EF 400mm f4 DO's....there is nothing to stop them developing a RF 400mm f2.8 DO.
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  6. There is a patent for a 400mm f2.8 DO and a 600mm f4 DO. The 600 f4 DO was seen as a singular prototype at a show a few years back.
    Just because Canon have alrfeady made two EF 400mm f4 DO's....there is nothing to stop them developing a RF 400mm f2.8 DO.
    Of course, and it could be a good way to differentiate a mark II RF 400 2.8. But I guess that's a fair way off.
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  7. I have had two copies of the Canon 400mm f/4 DO II, and my Nikon 500mm f/5.6 did not have better IQ. But, the Nikon was much lighter and about half the price here. The DO/PF lenses all suffer performance against bright backgrounds because of the zero-order spectrum of the diffraction grating. But, you need the light behind you anyway. My RF100-500mm at 500mm outperformed the DO at 400mm, and a 400/4 has only 1 stop more photons/duck than a 400/5.6 or 500/7.1. With a 2x TC at 800/8 it will be only 1/3rd stop faster than the 200-800 at 800mm f/9. Let's see how good it is and the price and the price and weight.

    These are the comparisons I was thinking about. The 200-800 at $1900 is going to be tough to beat for those of us who imagine using a 400+tc. I think the value proposition might only make sense for those who want to shoot at 400mm. This gets you there at a light weight sacrificing one stop of light vs the 400 f/2.8 (a $12k lens) at a lower cost. But the EF 400 DO is still $6,900! I just don't see how the RF version can support even that level. When the EF version came out, effective 600mm at f/8 was the sweet spot achievable with pretty good glass in the $2k range. The 400 f/4 with extenders would get you 560 at f/5.6 or 800 at f/8., thus giving it a reason to exist beyond 400 prime shooting. The new RF 800 at f/9 for under $2k kills that.

    All of that is to say, EF price suggest $8k would reasonable, but I don't see why anyone would buy it at that price. You are down to 400 prime shooters who are pros, I don't think they are going to give up the subject separation to save $4k. But I'm not a pro, so I'll leave it there.
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  8. These are the comparisons I was thinking about.
    A stop of light always costs a lot of money. The 70-200/2.8L is almost twice the cost of the 70-200/4L. The 24-105/2.8L is almost three times the cost of the 24-105/4L.

    If Canon brings an RF 400/4 DO to market, it will be because they believe it will be profitable, and it will be priced accordingly.
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  9. These are the comparisons I was thinking about. The 200-800 at $1900 is going to be tough to beat for those of us who imagine using a 400+tc. I think the value proposition might only make sense for those who want to shoot at 400mm. This gets you there at a light weight sacrificing one stop of light vs the 400 f/2.8 (a $12k lens) at a lower cost. But the EF 400 DO is still $6,900! I just don't see how the RF version can support even that level. When the EF version came out, effective 600mm at f/8 was the sweet spot achievable with pretty good glass in the $2k range. The 400 f/4 with extenders would get you 560 at f/5.6 or 800 at f/8., thus giving it a reason to exist beyond 400 prime shooting. The new RF 800 at f/9 for under $2k kills that.

    All of that is to say, EF price suggest $8k would reasonable, but I don't see why anyone would buy it at that price. You are down to 400 prime shooters who are pros, I don't think they are going to give up the subject separation to save $4k. But I'm not a pro, so I'll leave it there.
    More about my 2 EF 400mm DO IIs. The first I used very happily for several years as great for BIF at 400/560mm and for perched at 800mm. I sold it when I went over to the 500/5.6 PF, but then bought a second used copy cheap when I went to the R5. But, I never used it when I got the 100-500 and sold it at a profit. No way I'd buy another if it is up in the high thousands. (Do you mean there will be only 400 shooters;)?)
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  10. I would like to see Canon take DO, BR, and whatever other tech acronym they've got and use it to make a 400 f2.8 that weighs in at 2kg or less. That would be a big win.

    As for Rf 400 f4 DO it should weigh less than Sony's new 300 f2.8, preferably 1.2kg or less.
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