The silly state of dual memory card.

[mickledore]

If you're that disgruntled with the problem then swap to a camera system without these faults

IIRC OP sold his Canon gear and went to Fuji. Then he had a rant about Fuji and sold up. Back to Canon. If I'm right there seems to be a pattern here.

 

[Canon Bob]

What's the alternative?

Sell 20k of Canon gear and switch over to Nikon? and loses out on the 85/1.2, the EXRT flashes, the TSE lenses that I have?

What is the alternative? really?

Not being flippant but get a Canon body that will do what you need....a 1DxMKII which has a more than adequate buffer (around 170 raw) and isn't slugged by an SD card.

 

[niko]

IIRC OP sold his Canon gear and went to Fuji. Then he had a rant about Fuji and sold up. Back to Canon. If I'm right there seems to be a pattern here.

i think the fuji was used as travel kit and the canons were to be kept for his wedding work rather than sold. Raymond upgrades his canon 5 series bodies each time the new version comes out. the pattern is- p***ed that the slots on them don't change (seen the same rant in the past on a different forum). btw Raymond produces some lovely work on his "gimped " 5ds

 

[Raymond Lin]

If you're that disgruntled with the problem then swap to a camera system without these faults

So your solution is to switch to Nikon?

And it’s not a fault, it’s a stupidly in design decision that continues to happen when it shouldn’t. I’m disgruntled at the decision making by the people, not the camera.

 

[Raymond Lin]

IIRC OP sold his Canon gear and went to Fuji. Then he had a rant about Fuji and sold up. Back to Canon. If I'm right there seems to be a pattern here.

You got it wrong, I never sold any canon gear, the Fuji are my “toy” camera. And I still have them both.

 

[Raymond Lin]

Not being flippant but get a Canon body that will do what you need....a 1DxMKII which has a more than adequate buffer (around 170 raw) and isn't slugged by an SD card.

That is almost as expensive solution as switching to Nikon.

What frustrates me and baffles me is this.

5D2 - single card
5D3 - dual card
5D4 - same dual card 5 years later, UHS-II has been out a while at this point.

Where is the progress?

And Sony’s new A7R3 is the same, as is the brand new A7III.

Who makes these decisions?

 

[GordonM]

To be honest I’d suggest comparing confetti shots and sports is is actually unfair to sports photographers. The arguement that a single piece of confetti will be in the way unless you take 200 photos seems strange. I’ve shot weddings and most people expect that confetti will appear in front of faces surely? On the other hand the only goal in a football match is an unpredictable event without the knowledge it’s coming, unlike a photographer telling the crowd when to throw

 

[redhed17]

I'm a little confused by your response.

In the first paragraph you say you can do 70 shots at 10 fps while writing to the SD card, and that you tend to do 1-4s bursts, and that you've never hit the limit.
This means (as far as I can tell) that the only impact on you of using a slower (=cheaper) second slot is that your camera has cost less.
While none of us know how much extra the camera would be with the faster second slot, there would almost certainly be some extra cost - which would be of no practical benefit to you.

So why is their selling a camera without an unnecessary (to you, and probably to many of it's purchasers) extra function inexcusable?

Sorry for any confusion. The D500 does not have a much slower second SD card slot, it being UHS-II compatible. The 70 files to the SD card I mentioned was writing to only the SD slot with a non UHS-II (95Mb/s) card. I don't know if that would reduce the buffer overall if used with the faster XQD card. It is normally the slower slot, and then the slower card, which limits the depth of the Buffer at whatever frame rate.

So just did some testing with the D500 and Lexar 32GB 2933x XQD 2.0 Card and the fastest Lexar Professional 32 GB Class 10 UHS-II 2000x Speed (300 MB/s) SDHC.

RAW files to each card in 'Backup' varied between 56, 67 and 71 files on three attempts at 10fps. Not sure what changed, but the subject and lighting didn't.

RAW to the XQD did 199 @ 10fps
RAW to the SD did 198 @ 10fps

RAW to the XQD and JPEG to the SD did 77 @ 10fps. Seems there is not as huge benefit to RAW + JPEG over RAW + RAW as I would have expected. All that does me. It is nice to have a larger Buffer than I may usually need, and not frequently hit the limit, for the times when something special may happen in front of me.

I can't see why the animosity when someone asks a question about the design path a manufacturer takes. Asking the question may elicit an answer from someone who may have the answer as to why that design choice was made. Asking the question may draw together others who may have the same problem with the design choice, and so enable people to see whether it is just a problem for them, some or many others. Asking the question may get a solution to said problem which the OP may not have thought of/considered. Is that so wrong?

The D500 costs half the price of the 5DIV, has you would think, a more expensive XQD slot (for various reasons) AND a UHS-II slot. I would expect the 5DIV to have two UHS-II card slots. Again, if the question isn't asked as to why that is not the case, no answer will ever be forthcoming.

And I know the D500 and the 5DIV are aimed at photographers of different types of subjects, but the 5DIV is almost twice the price, yet the 'cheaper' camera has two fast card slots. And what is the betting that a 7DII replacement, should it ever appear, will do something similar with regards to one fast and one slow card!

 

[Eloise]

I’m only guessing here... but is suspect there is a SD Card interface which offers 1x UHS-II and 1x UHS-I interface (probably also offers USB and maybe the Bluetooth and WiFi connections too) and for for various reasons that’s what Canon and Sony have chosen - probably its low powered and therefore not needing high heat dispersion either. It’s not like Canon or even Sony probably design these interfaces themselves, it’s what is available “off the shelf” as it were.

 

[Raymond Lin]

To be honest I’d suggest comparing confetti shots and sports is is actually unfair to sports photographers. The arguement that a single piece of confetti will be in the way unless you take 200 photos seems strange. I’ve shot weddings and most people expect that confetti will appear in front of faces surely? On the other hand the only goal in a football match is an unpredictable event without the knowledge it’s coming, unlike a photographer telling the crowd when to throw

I didn’t bring up sports photographers, in fact I have not mentioned them at all. Someone brought up motor sports first and I compare it to that.

If you open the door to that then I’ll go in it. So to speak.

If you want to talk about football then let’s....you can’t tell when the goal is coming...how about when someone kicks the ball? That’s often a big tell tell sign. Or when the ball is crossed into the penalty box or a penalty or free kick close to the goal.

That’s your que. you can always tell when there is a higher chance of a goal score, if it’s at the corner flag and you are waiting at the opposite end...is it coming? Hell no. A player is injured, whistle is gone, is the goal coming? Really?

You know there is a higher chance when the ball is closer to the goal and you can always tell when some is about to kick it, someone need to kick the ball for it to score and between the ball leaving the foot to into the goal is a split second, it’s not a 20seconds movement. You see a foot get pull back, you burst a 3 second shot, job done.

Then there’s the point that sports photographers shoots jpeg. For pure speed, that photo is never retouched more than exposure and it’ll be online within minutes. You are not shooting raw and the file size are smaller.

Look, I don’t want to compare any of this...only when people bring it up.

As for “expected” to have confetti on their face....I’m not sure about your experience and standard of what’s a good confetti shot but won’t it be nice if you can get a nice one where you can catch a good smile and your face is not covered in the stuff? But yet there are confeffi in the air?

My standards are higher?...it’s not strange, I’m just seeking for a better photo...if people don’t expect this and I deliver it, it looks good on me and the client will be happy and honestly, why wouldn’t you try and aim for a better photograph. Why are you just trying for an ordinary bad photo and be happy with it. Shouldn’t you aim for the sky? It baffles me why you would settle.

Seriously, you will get people ask “is there a way to clone this out?” “I love this photo buy my hair is over my shoulder and I can’t see the strap on the dress”.

 

[Raymond Lin]

Sorry for any confusion. The D500 does not have a much slower second SD card slot, it being UHS-II compatible. The 70 files to the SD card I mentioned was writing to only the SD slot with a non UHS-II (95Mb/s) card. I don't know if that would reduce the buffer overall if used with the faster XQD card. It is normally the slower slot, and then the slower card, which limits the depth of the Buffer at whatever frame rate.

So just did some testing with the D500 and Lexar 32GB 2933x XQD 2.0 Card and the fastest Lexar Professional 32 GB Class 10 UHS-II 2000x Speed (300 MB/s) SDHC.

RAW files to each card in 'Backup' varied between 56, 67 and 71 files on three attempts at 10fps. Not sure what changed, but the subject and lighting didn't.

RAW to the XQD did 199 @ 10fps
RAW to the SD did 198 @ 10fps

RAW to the XQD and JPEG to the SD did 77 @ 10fps. Seems there is not as huge benefit to RAW + JPEG over RAW + RAW as I would have expected. All that does me. It is nice to have a larger Buffer than I may usually need, and not frequently hit the limit, for the times when something special may happen in front of me.

I can't see why the animosity when someone asks a question about the design path a manufacturer takes. Asking the question may elicit an answer from someone who may have the answer as to why that design choice was made. Asking the question may draw together others who may have the same problem with the design choice, and so enable people to see whether it is just a problem for them, some or many others. Asking the question may get a solution to said problem which the OP may not have thought of/considered. Is that so wrong?

The D500 costs half the price of the 5DIV, has you would think, a more expensive XQD slot (for various reasons) AND a UHS-II slot. I would expect the 5DIV to have two UHS-II card slots. Again, if the question isn't asked as to why that is not the case, no answer will ever be forthcoming.

And I know the D500 and the 5DIV are aimed at photographers of different types of subjects, but the 5DIV is almost twice the price, yet the 'cheaper' camera has two fast card slots. And what is the betting that a 7DII replacement, should it ever appear, will do something similar with regards to one fast and one slow card!

Someone get it and Yes, shooting Raw + Raw is faster than Raw + JPEG. May be because the camera need to convert one which uses up processing power but shooting jpeg as a “backup” is not faster...besides the point that JPEG is not true back up. I digress, costs can’t be a reason they can’t do it, can’t be lack of technical know how. I honestly can’t think why besides trolling us...

And yes, If I don’t ask these questions, and rant, they won’t fix it. This issue needs to be sorted, people shouldn’t be fighting me, if they fix this, it benefits everyone, I mean who will lose out having 2 x UHS-II slots?

 

[Raymond Lin]

I’m only guessing here... but is suspect there is a SD Card interface which offers 1x UHS-II and 1x UHS-I interface (probably also offers USB and maybe the Bluetooth and WiFi connections too) and for for various reasons that’s what Canon and Sony have chosen - probably its low powered and therefore not needing high heat dispersion either. It’s not like Canon or even Sony probably design these interfaces themselves, it’s what is available “off the shelf” as it were.

The 5D4 has built in WiFi....

 

[MatBin]

The D5 does appear to have 2 high speeds slots, but it is 'only' 20MP at 12FPS max (240 MP/s)
The D850 only has one QXD, the second slot begin SD - 45Mp at 9FPS is (405 MP/S)

The A9 is 24MP at 20 FPS (480 MP/S)

5D4 is 30MP at 7FPS (210 MP/S)

So clearly the 5D4 'could' have dual slots (as the D5 does), but it may be that the increased bandwidth requirements in the D850 and A9 make this more expensive.

An interesting experiment (if it's not been done already) would be to test how the dual slots actually perform
Shoot a static scene, so AF between shots is not an issue
1) Shoot at max burst using just slot 1 until camera slows, note time to fill, number of shots, and time to clear
2) Repeat with just slot 2
3) Repeat with writing identical to both slots

This would show how much faster the higher speed slot actually performs over the slower slot (comparing 1 and 2), and also if shooting dual slots is actually slower than just shooting to the slower slot (IE is the dual write truly parallel).

Done a while back when the 5D3 came out, the SD card seriously slows the write speed, to the point of it being virtually useless and useful only as a post shoot backup plan. Haven't seen a comparable test on 5D4 of 1DX1 or 2.

 

[Riz_Guru]

If you was speed/performance get the Sony A9, yes it has one slower UHS-I and one faster UHS-II slot but the buffer is big.
20fps with a 241 RAW / 362 JPEG buffer.

 

[Eloise]

The 5D4 has built in WiFi....

I think you slightly misinterpreted what I wrote Raymond... I meant where offered by the camera, the WiFi and Bluetooth may all be interegrated into the same chip that provides SD Card interfaces. The point being it’s not just about what is technically possible, but about what is available and fits into the space on the circuit board and takes the allocated power, etc.

 

[Brazo]

Isn't the Sony reason something to do with the slower slot still being compatible with Memory Sticks?

Yup wouldn’t want to lose the memory sticks! Nor the floppy drive at the back

 

[jonneymendoza]

Nikon can do it.

Everything else is an excuse.

Nikon d850 does have dual CF cards?

 

[jonneymendoza]

I believe the problem is actually down to the amount of heat the SD cards / Slots generate as they are having to shift so much data about. At present having two UHS-II Slots was/could cause too much internal heat for the body to handle.
I suspect the next generation Sony A9 body might go up in size and contain 2x UHS-II slots, however writing RAW to both the UHS-I and UHS-II Slots in the Sony A9 doesnt affected write speeds too much in real-world usage.

Didn't you say once that it faster to write dual raw Vs raw and jpg?

 

[Riz_Guru]

Didn't you say once that it faster to write dual raw Vs raw and jpg?

I believe so as the camera converts from RAW to JPEG before writing to the slot hence adding an additional processing overhead which slows down the write speeds.
However the positive outcome is if you setup playback from the JPEG slot the review process is snappier with a better zoom-in function on images.
Don’t quote me on the above as I’d have to double check but this is how I believe it works.
To be fair the Sony A9 buffer depth is big and for me writing RAW + RAW or RAW + JPEG doesn’t make a difference.

 

[markyboy.1967]

Nikon d850 does have dual CF cards?

D850 has an XQD and UHS 11 SD slot.

 

[jonneymendoza]

What's the alternative?

Sell 20k of Canon gear and switch over to Nikon? and loses out on the 85/1.2, the EXRT flashes, the TSE lenses that I have?

Or get Canon to fix this obvious flaw? No system is perfect but what i am asking is not a lot is it?

I mean is that that "insanity" to you?

or is the "sane" solution to do the switch then come back and moan about the lack of EX-RT flashes, how shooting they don't have dual pixel AF, etc etc?

What is the alternative? really?

1dx MK2? Or sell up shop as honestly your client's won't notice how there portraits wasn't taken on a canon glass.

Be honest Ray...

 

[jonneymendoza]

I’m only guessing here... but is suspect there is a SD Card interface which offers 1x UHS-II and 1x UHS-I interface (probably also offers USB and maybe the Bluetooth and WiFi connections too) and for for various reasons that’s what Canon and Sony have chosen - probably its low powered and therefore not needing high heat dispersion either. It’s not like Canon or even Sony probably design these interfaces themselves, it’s what is available “off the shelf” as it were.

I saw a tear down in the Sony and the UHS 2 slots have a beefy heatsink on them and there no way they can fit another UHS 2 slot without increasing the body size

 

[Phil V]

How did we manage in film days then?

No backup then. We just just relied on our equipment and we got on ok. At least I did.

But what we shot was different, and client expectations were different.

And whilst I don’t fall into Raymond’s rabbit holes, I do understand where he’s coming from.

 

[Raymond Lin]

1dx MK2? Or sell up shop as honestly your client's won't notice how there portraits wasn't taken on a canon glass.

Be honest Ray...

Be honest, I shouldn’t have to do that for what is essentially an industry standard part. What’s so special about a uhs-II slot anyway?

Why are you so against it? What benefit does it have for them to continue to do this for you or us?

 

[jonneymendoza]

Be honest, I shouldn’t have to do that for what is essentially an industry standard part. What’s so special about a uhs-II slot anyway?

Why are you so against it? What benefit does it have for them to continue to do this for you or us?

I'm not against it# I'm well behind you mate

 

[Icee]

It"s not the card speed that is the problem it's the buffer.

 

[cosmicma]

i think it will have more to do with marketing than a design flaw

by giving the 5d mk4 the same write / speed capabilities as the next camera in line it will lessen the potential market for that camera

both cameras are aimed at different markets i don't think canon or any of the other makes want to compromise sales of models within their line up maybe this is the reason why we see the obvious compromises within the different models

 

[Gaz J]

It"s not the card speed that is the problem it's the buffer.

On the 5D4 the write speed isn't that great when shooting full size raw to both cards and that's with a160mb/s CF and a 90mb/s SD.

Buffer gives around 17 frames before it slows down but it takes a while to clear the buffer back to max again. I can see how this would be a pain if you need that back up.

On my 1DX2 I gave up after a 100.

 

[redhed17]

i think it will have more to do with marketing than a design flaw

by giving the 5d mk4 the same write / speed capabilities as the next camera in line it will lessen the potential market for that camera

both cameras are aimed at different markets i don't think canon or any of the other makes want to compromise sales of models within their line up maybe this is the reason why we see the obvious compromises within the different models

What is the next camera in their range, the 1DXII? It is not as big a change in resolution as Nikon have with the D850 and D5, but Nikon put a XQD AND SD UHS-II socket in the D850. Yes, the D5 has either two CF slots or two XQD slots, so not exactly the same configuration, but they haven't hobbled the second card slot as Canon have done with a lower resolution camera.

 

[cosmicma]

What is the next camera in their range, the 1DXII? It is not as big a change in resolution as Nikon have with the D850 and D5, but Nikon put a XQD AND SD UHS-II socket in the D850. Yes, the D5 has either two CF slots or two XQD slots, so not exactly the same configuration, but they haven't hobbled the second card slot as Canon have done with a lower resolution camera.

on the canons the reason for the faster card slot is more to do with 4k video than stills
i know on the 1dx 2 unless you have the fastest cf cards on offer you cannot record 4k to the cf card it has to be written to the Cfast card because of the data rate
maybe it's the same scenario with the 5d mk4 but i have never owned a 5d mk4 so i don't really know

 

[redhed17]

on the canons the reason for the faster card slot is more to do with 4k video than stills
i know on the 1dx 2 unless you have the fastest cf cards on offer you cannot record 4k to the cf card it has to be written to the Cfast card because of the data rate
maybe it's the same scenario with the 5d mk4 but i have never owned a 5d mk4 so i don't really know

Regardless of why they have had to go CFast in the 1DXII, they have hobbled the second slot on the 5DIV, which also does 4k video, especially if only the fastest CF cards can do 4k in their cameras. Maybe they should have gone CFast and SD UHS-II in the 5DIV, if that is what they are going with the top level cameras. Nikon have taken the bold step of two XQD or two CF in the D5 rather than a mix. They have also brought the XQD slots into their next camera, the D850, and their top crop sensor camera in the D500. Maybe Canon should be doing that with CFast.

Once you start having different formats in dual slots during the transition between new/old formats, it is a delicate balancing act as to what a manufacturer chooses. They have to take into account what cards current users have, and maybe the availability and cost of new formats. There may also be technical things to take into account too. Not using the fastest option of whatever format slots chosen still seems stupid in such expensive/high performance cameras. And if you don't put the new formats in multiple cameras the availability will not increase for users if there is not a bigger demand, and so prices may not come down.

As it is, no one knows for definite why they have chosen why they have done what they have with the SD slot. Maybe it will marketed as new feature of a 5DV as large camera/performance developments are harder to achieve. Maybe the OP will eventually get what he needs with a 5DV, as it looks like he won't be changing brands any time soon.

 

[Faldrax]

Sorry for any confusion. The D500 does not have a much slower second SD card slot, it being UHS-II compatible. The 70 files to the SD card I mentioned was writing to only the SD slot with a non UHS-II (95Mb/s) card. I don't know if that would reduce the buffer overall if used with the faster XQD card. It is normally the slower slot, and then the slower card, which limits the depth of the Buffer at whatever frame rate.

So just did some testing with the D500 and Lexar 32GB 2933x XQD 2.0 Card and the fastest Lexar Professional 32 GB Class 10 UHS-II 2000x Speed (300 MB/s) SDHC.

RAW files to each card in 'Backup' varied between 56, 67 and 71 files on three attempts at 10fps. Not sure what changed, but the subject and lighting didn't.

RAW to the XQD did 199 @ 10fps
RAW to the SD did 198 @ 10fps

RAW to the XQD and JPEG to the SD did 77 @ 10fps. Seems there is not as huge benefit to RAW + JPEG over RAW + RAW as I would have expected. All that does me. It is nice to have a larger Buffer than I may usually need, and not frequently hit the limit, for the times when something special may happen in front of me.

I can't see why the animosity when someone asks a question about the design path a manufacturer takes. Asking the question may elicit an answer from someone who may have the answer as to why that design choice was made. Asking the question may draw together others who may have the same problem with the design choice, and so enable people to see whether it is just a problem for them, some or many others. Asking the question may get a solution to said problem which the OP may not have thought of/considered. Is that so wrong?

The D500 costs half the price of the 5DIV, has you would think, a more expensive XQD slot (for various reasons) AND a UHS-II slot. I would expect the 5DIV to have two UHS-II card slots. Again, if the question isn't asked as to why that is not the case, no answer will ever be forthcoming.

And I know the D500 and the 5DIV are aimed at photographers of different types of subjects, but the 5DIV is almost twice the price, yet the 'cheaper' camera has two fast card slots. And what is the betting that a 7DII replacement, should it ever appear, will do something similar with regards to one fast and one slow card!

I wasn't trying to be antagonistic at all - it was your statement that the 'issue' was unlikely to have any relevance for you, yet you thought it inexcusable that it existed that confused me.

The test results you give are interesting.
If I am interpreting them correctly, writing to both cards at once more than halved the buffer capability, compared to writing to just one card!

If this is the case, then the reason for 1 fast, 1 slow in other models becomes clearer - there is no benefit to having 2 fast slots for backup mode, because the overhead of writing the data twice halves the ability to clear the buffer, so the transfer from buffer to card is the limiting factor, rather than the simple write speed of the card.

Obviously, having 2 fast slots does have other advantages - and as cameras gain ever increasing levels of processing power, internal bandwidth, etc, the bottleneck will change to the slower card slot at some point in time, but based on the above values a faster second slot is much less of an advantage than it might at first appear.

 

[MatBin]

The trouble is if you have write enabled to both slots with the 5D3 the SD write speed is the one which dictates the overall write speed so you end up with having to choose between live backup at slow write speed overall or decent write speed albeit with a small burst rate/buffer in raw mode and no live backup. I can't see why Canon didn't improve it for the Mk4, after all it came at a much bigger price than the Mk3 and a 1Dx2 is at another level again.
Matt

 

[rob-nikon]

This is an interesting thread. Having previously had a D750 that used SD cards in both slots then moving to a D810 that uses both SD and CF cards I know how much of a pain it can be seen as. Partly I think there is probably a design reason and historic user reason why canon have stayed with SD and CF cards whilst Nikon have started moving towards XQD and SD UHS-II cards in their latest cameras (D850 & D500) and xQDs in the D5. Only time will tell if it was worth the gamble so early on when new card types are still in their infancy, especially with XQD where there are limited manufacturers now Lexar have gone. I personally would say canon havent hobbled the 5d4 or 7d2 on purpose just that they haven't seen enough reason yet to make a potential risky jump. You only have to look at what Nikon did to the D7500 to see an obvious hobbling of a camera model for marketing purposes (single SD card slot and no battery grip option). It will be interesting to see what happens to the D750 replacement, I can potential see the 2 slots disappearing or the slower SD card slots staying to make a marketing differential between models.

 

[Raymond Lin]

I think you slightly misinterpreted what I wrote Raymond... I meant where offered by the camera, the WiFi and Bluetooth may all be interegrated into the same chip that provides SD Card interfaces. The point being it’s not just about what is technically possible, but about what is available and fits into the space on the circuit board and takes the allocated power, etc.

The 5D3 came out about 7 years ago, probably started its R&D 10 years ago.

That's how long they've had, and Sony too, have had to the recent release of the A7iii, if this is the limitation as you say….that is plenty of time to get around this problem.

The 5D3 is 22.3mp, 5D4 is 30.4mp, the A7iii is 24.2mp. Moore's law says that computing power doubles every 2 years….honestly, enough time have gone by for the CPU to cope with the 7mp increase in the 5D4 or the 2mp increase in the A7III.

I don't accept that the processing power or any kind of technical limitation is a factor, a LOT of time has passed between the release of the models, they would have a lot of feedback from people. But I still can't imagine an engineer would sit there and design something with 1 slot being slower when one of the feature is for back up. That should scream at you what would happen when you do that.

 

[redhed17]

I wasn't trying to be antagonistic at all - it was your statement that the 'issue' was unlikely to have any relevance for you, yet you thought it inexcusable that it existed that confused me.

I didn't think you were being antagonistic, just that I had not been clear in what I was trying to say. Obviously on the internet, when communication is in a written dorm, things can easily be misinterpreted.

The test results you give are interesting.
If I am interpreting them correctly, writing to both cards at once more than halved the buffer capability, compared to writing to just one card!

It seems that dual files more than halves the buffer capacity on the D500, and that is with the fastest SD card available in the UHS-II slot. And it looks like with the JPEG processing, it is not just files sizes which slows that camera.

If this is the case, then the reason for 1 fast, 1 slow in other models becomes clearer - there is no benefit to having 2 fast slots for backup mode, because the overhead of writing the data twice halves the ability to clear the buffer, so the transfer from buffer to card is the limiting factor, rather than the simple write speed of the card.

That is where the speed of the card slot could have an effect. Say if the camera is able to transfer data close to the speed of the card, then the speed the buffer clears is card related. I know that is an hypothesis. With only XQD card the D500 will do close to 200 shots, lift your finger off the shutter and it will start another 200 from what I have seen in reviews. The XQD card is that fast at clearing the buffer.

Obviously, having 2 fast slots does have other advantages - and as cameras gain ever increasing levels of processing power, internal bandwidth, etc, the bottleneck will change to the slower card slot at some point in time, but based on the above values a faster second slot is much less of an advantage than it might at first appear.

The camera is sending data to both cards if used, the faster the card slots (and cards) the faster any buffer will clear. The D500 does about 70 images @ 10fps a slower card, (95Mb/s) so card speed is already a limitation in that camera. I can't see a higher level/more expensive camera like the 5DIV buffer clearance not being affected by slower slots and or/slower cards being used. It was mentioned earlier that 4k video is being affected by the card speed used, so cards are affecting video already, and have been from the move to 1080p, nevermind 4k. Use a slot that is not capable of taking advantage of the faster cards, and the choice continues to look stupid. Imho.

 

[gramps]

Two expressions come to mind, "Always leave them wanting more" & "Designers don't make things, accountants do".

 

[Raymond Lin]

We can say buffer or cards used being a limitation, but one problem at a time, make both card slots the same, then the only other thing that slows it down is only down to the CPU or buffer.

 

[Raymond Lin]

Fuji X-H1 supports dual UHS-II slots.

So there goes the question whether heat is a problem, its the practically same mp count as the Sony A7iii, both have 5 axis IBIS. Both coming out in the same time.

 

[Raymond Lin]

This is an interesting thread. Having previously had a D750 that used SD cards in both slots then moving to a D810 that uses both SD and CF cards I know how much of a pain it can be seen as. Partly I think there is probably a design reason and historic user reason why canon have stayed with SD and CF cards whilst Nikon have started moving towards XQD and SD UHS-II cards in their latest cameras (D850 & D500) and xQDs in the D5. Only time will tell if it was worth the gamble so early on when new card types are still in their infancy, especially with XQD where there are limited manufacturers now Lexar have gone. I personally would say canon havent hobbled the 5d4 or 7d2 on purpose just that they haven't seen enough reason yet to make a potential risky jump. You only have to look at what Nikon did to the D7500 to see an obvious hobbling of a camera model for marketing purposes (single SD card slot and no battery grip option). It will be interesting to see what happens to the D750 replacement, I can potential see the 2 slots disappearing or the slower SD card slots staying to make a marketing differential between models.

When you are shooting dual cards, you are limited to the slower card so a fast CF card becomes almost redundant. I can imagine that if the next Canon just do dual SD cards and how it can be seen money wasted on all the CF cards that I have but the reality is that SD cards are much cheaper, not to mention I don't use the older cards that i bought years ago because they are like 30mb/s, 45mb/s.

Replacing all the CF cards with UHS-II cards isn't really that big a deal in the grand scheme of things.