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

If the R5 is rumored to be 45 MP at 20fps, is anyone concerned this will lead to a buffer issue for an SD card? That’s more lifting than the 1DX3.

unlike the 1DX Mark III that can shoot at 20 fps with a mechanicall shutter - the R5 cannot.

people seem to be keying on the 20 fps when in all practicality, the 12 fps is most likely going to be used most often because of the mechanical shutter.

I don't notice any real problems on the M6 II and that's with 16 fps and 32.5MP. around the same as 12fps and 45mp.

IMO, this issue is overblown.

Granted you have two dissimilar cards and the nonsense dealing with that - but Canon is going to leave some stuff off for the R1. You can't expect everything you dream of on the R5 when Canon has to turn around and try to convince you to get an R1 in a year's time.
 
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AaronT

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yup, the max speed of the Sandisk Extreme Pro 64GB read speed is up to 300mb/s and write speed of 260mb/s which is the important one as that is what determines how fast the buffer fills up. Thats why I was asking what card you have as 400mb/s is incredibly fast for a UHSII card
I was replying to someone else who said "A UHS II card can easily record 450mb/sec on my R." I never said that I had a UHS II card that could record that fast.
 
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why is a UHS-II SD slot suddenly useless?

It's not... I am a 5DMk IV shooter who also has the new 90D which has the single UHS-II slot which is fully backward compatible. I use both UHS-I and UHS-II cards in it ... no issues at all. The UHS-II is clearly faster especially at the speed the 90D can shoot 10 FPS. Given the high pixel density 32 MP of the 90D, a 64GB UHS-II does fill fast at that 10 FPS speed.
 
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Joules

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Are people even sure that the 20fps isnt a cropped burst mode like the M6 II? A lot of these calculations may be irrelevant as they're based on assumptions of full sensor and 14 bit.
We are not sure of that. But Canon's wording will cause them a lot of complaints if it is a crop mode. As the throughput of 40/45 MP 20 FPS is so high (nothing else comes close) I'm sure it won't have AF though.
 
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Card speeds , doesn't the new Canon system allow immediate download on to this new Canon transfer site they are creating ?
The blurb coming out says the R5 will be the 1st camera to be able to use the new cloud based storage, so great idea in principle but I would think it will still relay on the images being stored on the SD or CFE cards 1st before transfer and also rely on the speeds of internet connection either by wifi being available or via your own phone hotspot. Canon don't have a great track record with this kind of thing as the Canon Connect app demonstrates but you never know, they seem to be bringing out some excellent new tech with great software so this could be the 1st one to work. If so great news.
 
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We are not sure of that. But Canon's wording will cause them a lot of complaints if it is a crop mode. As the throughput of 40/45 MP 20 FPS is so high (nothing else comes close) I'm sure it won't have AF though.
Although the R is a fantastic stills camera, thats one thing I miss from my old 7D MKii as the R has a lot slower frame rate and even slower if AF is activated. Im sure Canon could do it with AF at 20FPS if they wanted to but not sure they will as it could detract from the 1DX MKiii and a future mirrorless version. The price would probably increase massively as well lol
 
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So you'll probably give up a bit of speed when using the SD UHS-II compared to the CFExpress, but that's still a pretty doggone fast card.

I would suspect that it would be backwards compatible with UHS-I SD cards as well, albeit at a more reduced buffer clearing speed.
I wonder if they will apply a similar option that the 1DX MKIII has of being able to assign each card to a different medium, i.e. one does stills and the other does video? That could be interesting and mean the UHS II SD could be used for stills and probably be able to cope with the frame rate and clear the buffer unless using 20fps for sustained periods. The CFE could easily cope with the video side even at 8k I would imagine with write speeds of up to 1200mb/s
 
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brad-man

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I don’t know why people are crazy about CFExpress cards price, they’re actually good deals, much faster cards with almost same price with ush-ii sd cards. Sandisk uhs ii 128gb is ~$200, CFExpress 128gb $200-$250.
While it is true that the price difference between UHS-ll and CFExpress is not that extreme, a camera that utilizes UHS-ll is backwards compatible and can use UHS-l when speed is not an issue. With CFExpress that is not the case. Since most folks (myself included) feel that multiple cards are required for piece of mind, it adds up to mucho dinero. In the future when more devices use both formats more frequently, economy of scale will kick in and prices will lower. But for now, ouch!
 
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Why not to use an internal super-fast solid drive (with a few capacity variants) instead of an SD card slot?
A CFE card would nicely work like a backup then...
I wondered about this myself with Flash storage getting cheaper and smaller. However I think Canon and the other manufacturers are worried about being as flexible as possible with removable storage being so much easier to keep safe and connect to other gadgets etc. However Mobile phones are now showing how large storage can be built into small items whilst retaining amazing ability to back up to cloud based storage and also be available on all you other connected devices. The Apple model is brilliant at this. The only downside is how it would cope with the massive file sizes of RAW images and the 20/25FPS burst rates. At present, Im not sure the technology is able to do this.
 
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Joules

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Im sure Canon could do it with AF at 20FPS if they wanted to but not sure they will as it could detract from the 1DX MKiii and a future mirrorless version.
In its fastest video mode the 1DX III does 5.5K 60 Hz but is unable to do AF. That amount of data coming from the sensor pretty much matches what the R5 will do at 20 FPS 45 MP. I think even if they wanted to offer AF in that mode, they can't. No crippling here, 45 MP at 20 FPS is simply a ridiculous throughput.

It's 150 % of what the A7 R IV does, 225 % of what the 1DX III does, 430 % of what the R does! There has to be a compromise.
 
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I wondered about this myself with Flash storage getting cheaper and smaller. However I think Canon and the other manufacturers are worried about being as flexible as possible with removable storage being so much easier to keep safe and connect to other gadgets etc. However Mobile phones are now showing how large storage can be built into small items whilst retaining amazing ability to back up to cloud based storage and also be available on all you other connected devices. The Apple model is brilliant at this. The only downside is how it would cope with the massive file sizes of RAW images and the 20/25FPS burst rates. At present, Im not sure the technology is able to do this.
Bear in mind too that SSD memory is "great", but it can (and does occasionally) fail (albeit it is much more reliable than spinning discs).

So, what do you do with the camera if the built in memory fails? It will be repairable of course, but not great for a working pro. You could make it easily replaceable.... if it is easily replaceable, why not just have a removable disk....and hey presto you're back to a card :D
 
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We are not sure of that. But Canon's wording will cause them a lot of complaints if it is a crop mode. As the throughput of 40/45 MP 20 FPS is so high (nothing else comes close) I'm sure it won't have AF though.

Thats another possibility. Without the whole picture, many of the assessments being made in this thread seem premature.
 
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