The Canon EOS R5 will have an SD & CFExpress slot [CR2]


Wildlife Shooter
Aug 8, 2018
You didn't need a failure to desire a system with a backup for redundancy to have peace of mind. I could use a single slot body, I don't NEED two slots but I have them and use them creatively, not for work/insurance/security. But I would not begrudge anyone who desires such a plan. It's silly to try and find holes in anyone's workflow. Do we all have to be the same? Please god no.
I am not a professional photographer, but I definitely appreciate 2 cards. I wouldn't drag around 30lbs of camera gear unless I had a desire to capture the best image possible. The last thing I want is to visit a unique location (Africa) and not go home with the great images I captured simply because a card failed. I carry the weight of two camera bodies to have a backup even if I only put a handful of shots on the 2nd body. I think anyone who spends the money for a R5, 5dIV, etc. doesn't want to loose a shot simply because a card failed.
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Jun 27, 2013
I don't know camera architecture, but you could potentially use a dual bus and dedicated memory to deal with the slower speed of the SD card. I doubt Canon is going to release a high end camera that degrades the performance to the lower value. I have used this approach with my 1dx II (granted with a CFast card) when I wasn't carrying a laptop on the trip. I didn't use the approach that often since I didn't want to buy a lot of CFast cards for backup:
  • Buy 2 128GB Cfexpress cards
  • Slot 1 (Cfexpress) 128GB Write RAW
  • Slot 2.(SD UHS II). 128GB Write high quality Jpeg for loading on my iPad for review
  • At the end of the day insert fresh SD "backup" card and use Image Copy to create a backup of the 128GB Cfexpress card. You couldn't envy ue one of the slower UHS I cards if you had time and didn't want to buy the more expensive cards.
There might be an option for HEIF format on this camera given Canon's recent push for this format. So users will have better file option other than JPEG.

This news makes me fear that the 5DV will also omit CF support. :(
CF format should be a relic of bygone era- IDE/PATA interface. With CFexpress supporting NVME over PCI-E 3.0 for current(technically still last gen with advent of PCI-E 4.0 interface) generation of industry standard interface. There are UHS-II Cards that are faster and even have higher capacity than even the fastest CF cards you can buy.
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EOS 5D Mark IV
Nov 1, 2012
Yes....But you have to understand that when you buy a camera or a type of camera, you don´t buy "only" the camera! You have to think about the hole ecossistem! If you buy a camera that pushes the limits of writing and ask for better cards you need to accept that you will need better cards. It´s like choosing fullframe or aps-c...If you choose fullframe you know you will need to invest more in lenses. Other wise whats the point of buying a FF?

So..if you are going to buy a camera like the 1dx mkIII or the EOS R5 yes..of course you will need to think about buying new cards And if you are not ready to buy those might want to think twice about buying those cameras!
Of course if you have already good SD cards and the R5 has a SD slot, you dont need those Cfexpress cards. But tell me, Will you buy the R5 without buying at least one cfexpress card?
Yes, but I just don't like when people say "if you can afford camera for $$$, then you have enough money for the $$$ memory cards too."

I still have to work for that money, it doesn't magically appear on my account. Especially after I already paying big bucks for the camera.

Naturally I understand the technical aspect, certain video (or still) modes require faster memory than what SD can provide, so of course Canon will add that type card slot.

I haven't ordered the 1DX3 yet, although I bought cards already as I got good deal through my friend. Those cards are expensive...


EOS M6 Mark II
Feb 1, 2012
I've long thought that Canon have a different purpose in mind when they provide cameras with two slots that write at the speed of the slower slot. On a long trip, you can use these cameras with only the faster card fitted. In the evening, you can copy your photos from the fast card onto the slower card, using the second slot in the camera and the firmware function provided. You don't need to carry a laptop, but can be backed up. Then, instead of fiddling with your photos on a laptop, you file then in a pouch and go off to dinner with your non-photographic travelling companions.

If you don't worry about backups, you can fill the expensive fast card multiple times by copying the files onto the slower format. You can buy and carry multiple slower cards totalling more storage than you have on your fast card. If your slow format is SD, there's a good chance you can buy more of them on your trip.

Meanwhile, it's mainly wedding photographers who need to be able to both slots simultaneously, and for them, speed isn't thatl important. So Canon provide a mode for that too, at the slow speed.

And that, I think, is Canon's reasoning. While I might personally prefer dual CFExpress because I keep cameras for a long time and don't have a large collection of SD cards, I think their reasoning is correct for the majority of buyers.


Nov 22, 2017
Because it is a bottleneck, and it prevents those with the good sense to use two CF cards. Why buy a high end camera then skimp on necessary parts? If you want cheap, just use one card.


EOS RP + 5D Classic
Aug 31, 2018
Why Canon, why? CF Express on both would bring speed to life as we know it ???
Wait for the R1, then.

No offense to Mr. Toes, or any other poster, but this thread is bananas. I can't imagine a less controversial Canon decision than this; every 5D since the mark II has had mismatched slots. It's a feature of the line by now. Deal with it, or buy something else.


Sep 13, 2011
Awesome news as you can get CFexpress cards larger than 128gb. UHS-ii's seem limited to 128 (for the last three years).
Sep 4, 2018
I shoot weddings, events and music concerts with a 5D3. I shoot raw to 2 32gd SD cards and swap them out often and in pairs. Only time I hit the buffer is if I get over excited at a concert and overshoot.

I could get bigger cards but I don't need them.

I'd be interested to see if there's a CFExpress to SD adapter I can use.

For my needs CFExpress is still too expensive but I like having the option should I need it in future.
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Dec 31, 2012
well actually, the fast SD-cards are more expensive than slow CFexpress cards (which are much faster still): I found
CFExpress: DeLOCK Flash R1550/W900: 256GB, write speed 900 MB/sec for 150 €
SD: UHS-II: Toshiba Exceria Pro N502 R270/W260: 256GB, write speed 260 MB/sec for 300 €

So, its a design decision by Canon which I cannot understand. It may only be that it is space constraints.

By the way, for my 5D3 I have 128GB CF + SD cards and I record dual RAW to both cards. I find the SD more convenient to remove in order to put into a card reader on the computer. With the R5 I probably would transfer the RAW files by WiFi.


EOS M6 Mark II
Aug 24, 2016
People are going to buy a hideously expensive Canon R5 camera and suddenly can't afford the CF express cards for it? The high speed SD UHS-II cards are not dramatically less expensive.
Thanks for your opinion. Care to share your insider knowledge about pricing with us? Apparently you know a lot about it.
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Dec 18, 2011
While I like symmetric systems the different cards might be a good move for me: I have some notebooks which have built in SD card readers and it's great to have direct compatibility for all the standard stuff (stills, p1080 and p2160 video) - and if I really need the "fast stuff" I have the option of CF express.

Maybe it is a bottleneck in the controllers to: Writing insanely high data rates to two devices simultanously isnt't twice the computing power but maybe 20% more!