# More Canon RF 400mm f/2.8L IS USM information



## Canon Rumors Guy (Apr 13, 2021)

> Canon will be officially announcing an RF 400mm f/2.8L IS USM super-telephoto lens. This lens is optically identical to the EF 400mm f/2.8L IS USM III. I do wonder if this and the RF 600mm f/4L IS USM will be stopgaps while Canon designs new super-telephoto lenses to take full advantage of the RF mount.
> The Canon RF 400mm f/2.8L IS USM will launch at $11,999 USD.
> Below is official Canon information about the RF 400mm f/2.8L IS USM.
> High-performance, Wide-aperture 400mm f/2.8 Super-telephoto Lens, Exclusively for EOS R-series cameras
> Inheriting the optics of the EF 400mm f/2.8L IS III USM, the same high image quality is maintained in the RF400mm F2.8 L IS USM with outstanding sharpness and contrast, center to corner, even at maximum aperture. A combination of Fluorite and Super UD (Ultra-low Dispersion) glass is at the heart of this lens’s outstanding optical performance. At the widest aperture of f/2.8, chromatic aberration is significantly reduced, to achieve tack-sharp images...



Continue reading...


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## DJL329 (Apr 13, 2021)

Wow.  

I was so _sure_ those photos were fakes! I can't believe Canon just retro-fitted the existing EF lenses to RF.

Now I'm wondering if it'll be the same for the RF 300mm and 500mm versions.


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## Canon Rumors Guy (Apr 13, 2021)

DJL329 said:


> Wow.
> 
> I was so _sure_ those photos were fakes! I can't believe Canon just retro-fitted the existing EF lenses to RF.
> 
> Now I'm wondering if it'll be the same for the RF 300mm and 500mm versions.



I really don't think these will be around for very long. The 300 and 500 will definitely be new optical designs.


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## Joules (Apr 13, 2021)

I'm surprised that there's a market for these things. How many people are interested in these, but have not bought the EF version yet and also hate dislike adapters enough to justify a permanently attached one?


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## HenryL (Apr 13, 2021)

Joules said:


> I'm surprised that there's a market for these things. How many people are interested in these, but have not bought the EF version yet and also hate dislike adapters enough to justify a permanently attached one?


I know at least one...


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## john1970 (Apr 14, 2021)

As much as I wished Canon had a new optical design I do understand that these two lenses were only redeveloped two years ago so it makes sense that they would do a retrofit. This is along the lines of what Canon did with the 1200 mm f5.6 years ago, where it was originally a FD mount, but they later retrofitted to a EF mount. I am also looking forward to seeing what Canon does with the RF 500 mm f4, which has not been redesigned since 2011.


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## richperson (Apr 14, 2021)

Joules said:


> I'm surprised that there's a market for these things. How many people are interested in these, but have not bought the EF version yet and also hate dislike adapters enough to justify a permanently attached one?



I'm somewhat glad as it keeps me from feeling like I'm missing something by keeping my older glass. I will be very curious to see what they do with the 200-500mm f/4. It would be great if they could find a way to lighten that one up.


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## padam (Apr 14, 2021)

Joules said:


> I'm surprised that there's a market for these things. How many people are interested in these, but have not bought the EF version yet and also hate dislike adapters enough to justify a permanently attached one?


People buying these prime lenses will also likely to use teleconverters, and the RF teleconverters should perform much better, it was designed like this from the start, both providing an upgrade for EF users as well as starting the new RF super telephoto line-up.


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## Deleted member 381342 (Apr 14, 2021)

Still looks a bit odd. And of course there is no focus window. And why aren't the TC's silver? Canon lenses where always rather nice looking and stood out, this looks like it was rushed out.


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## privatebydesign (Apr 14, 2021)

john1970 said:


> As much as I wished Canon had a new optical design I do understand that these two lenses were only redeveloped two years ago so it makes sense that they would do a retrofit. This is along the lines of what Canon did with the 1200 mm f5.6 years ago, where it was originally a FD mount, but they later retrofitted to a EF mount. I am also looking forward to seeing what Canon does with the RF 500 mm f4, which has not been redesigned since 2011.


Not really, regarding the FD1200 they took them all back to the factory (Canon never sold an FD 1200 but lent them out) and rebodied them completely, they also took out the built in 1.4 TC and made them auto focus. I think you’d have to agree that is a bit more than just changing mount.

What would be more interesting is if they felt the pressure to reverse mount any new RF design to EF like they did with the EF 200 f1.8 when they made a very limited number of FD 200 f1.8’s after pushback from some pros.


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## Jethro (Apr 14, 2021)

Is the IS the same as on the EF version - or have they upgraded it?


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## Traveler (Apr 14, 2021)

No surprise at all. I said it multiple times that those big telephoto ones are the least in a rush – they are already big and expensive so putting an adapter on each of them doesn't make them significantly more expensive or bigger. 
I understand that professionals don't want to bother with "another part that can break" (as they say) so this is just the answer from Canon. Another factor is the ability to use TC – I didn't think of it before.
I guess they'll make new designs in the future but probably nothing that couldn't have been done with the EF mount (talking big primes).


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## Ekpil (Apr 16, 2021)

Fake RF Lenses 
I own both the 400mm and 600mm EF lll when I start comparing the fotos against my lenses. The original Canon photos are showing the latest EF plus a silver adapter/converter that my be fixed ? 
Every new real RF Lense has a control ring. Where ist it ? The length has to be corrected to +25mm (converter EF RF) 
Minimum focus distance in the specs is the same. This is same same but different ;-)

We have to wait. 
Maybe the marketing is selling that as the first RF Lens that you can convert to EF.


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