Canon 5D MKIV dual memory card question

JRPhotos

5D4, 24-105LII, 70-300L, 35 1.4II, 85L 1.2II, 100L
Jan 19, 2014
118
1
Maine
www.jrogdenphotography.com
I use the SanDisk 32GB Extreme Pro CompactFlash Memory Card (160MB/s) but am thinking about getting the SanDisk 64GB Extreme PRO SDXC UHS-I Memory Card and have the camera write to both cards at the same time for a backup.

Will I see any performance loss?
 

pwp

EOS 5D MK IV
Oct 25, 2010
2,530
22
JRPhotos said:
I use the SanDisk 32GB Extreme Pro CompactFlash Memory Card (160MB/s) but am thinking about getting the SanDisk 64GB Extreme PRO SDXC UHS-I Memory Card and have the camera write to both cards at the same time for a backup.

Will I see any performance loss?
The buffer may take a touch longer to flush. If there is a performance loss, you'll only see it when you're doing deep continuous bursts. It's a very simple matter to test using different card configurations. Just shoot RAW, high speed continuous and time when the buffer starts to stutter.

When I'm shooting sports, I'll write to two cards on the 1DX (twin CF) but with the 7DII I take out the SD and shoot CF only.

-pw
 

SecureGSM

2 x 5D IV
Feb 26, 2017
1,626
584
In 3 words: yes, you will.

As CF interface is faster than SD on the Mark IV.
Take a look the following page:

https://www.cameramemoryspeed.com/canon-5d-mark-iv/sd-cf-card-speed-test/

CF 98 vs SD 74 images taken in 30 seconds - continuos shooting

It may will or won't make a difference for your style of shooting. But numbers are there for you to consider.
I personally shoot writing to both cards simultaneously. Redundancy is more important for me.
 

Mikehit

EOS 5D MK IV
Jul 28, 2015
3,277
474
I have tried both SD card and CF card in my 7D2 and both give up to 50-shot burst before slowing down which suggests there is little time difference in buffer clearance. Seeing as I can't think of a time I did a burst in excess of 6 seconds I am happy to use either.
 

SecureGSM

2 x 5D IV
Feb 26, 2017
1,626
584
HI Mike,

the OP's question was about 5D IV though. SD and CF card slot throughput is different for your cam.
5D IV numbers are a bit better as they should for the newer cameras anyway.


Mikehit said:
I have tried both SD card and CF card in my 7D2 and both give up to 50-shot burst before slowing down which suggests there is little time difference in buffer clearance. Seeing as I can't think of a time I did a burst in excess of 6 seconds I am happy to use either.
 

Mikehit

EOS 5D MK IV
Jul 28, 2015
3,277
474
Hi securegsm - I realise that, I should have been more clear in saying if I do not note a performance hit on the 7D2 I very much doubt it will be an issue with the 5DIV if you are using the fastest cards of either type.
 

Mt Spokane Photography

I post too Much on Here!!
Mar 25, 2011
15,642
830
A SD Card is SLOW! The figures they give are for suckers! The write speeds are what you get only under special circumstances when the card is new, otherwise, you will get about 10-20 Mb/sec.

The simple reason is that once a card has been used, a block erase cycle must be done before the old data on the card can be overwritten. That is a slow process, so it doesn't matter much how fast the card can write if the camera must first wait for a erase cycle.

You can get around this by doing a low level format before using a card, but, of course, 500 of those and the card is toast.
 

BasXcanon

EOS T7i
Oct 6, 2016
83
5
I know this is not for every one..... but have you considered setting your DOF preview button to One touch image quality??? I can write Raw + JPEG to my cards in a burst, when I notice the raw buffer is filled , I hold the One touch IQ and it continues on unlimited jpeg only.
 

Mt Spokane Photography

I post too Much on Here!!
Mar 25, 2011
15,642
830
SecureGSM said:
oh.. not 500. please :)
I exaggerated, Its probably more like 150,000 write cycles before 10% of them fail, but I'd avoid low level formats until they are needed, such as before a long video.
 

Frodo

EOS RP
Nov 3, 2012
307
21
Hi MSP, is that even an issue? A daily format gives 1000 in three years. At which point, you'd probably upgrade the card, which would have paid for itself.
I do a non-low-level format each time I upload images. But then this is for a 6D.
 

RGF

How you relate to the issue, is the issue.
Jul 13, 2012
2,816
35
as other have said it is slower to write to a SD than a CF card.

Implications:

If you never fill the buffer and wait for sufficient time for the buffer to be written, you will not see a performance difference.

If on the other hand, you fill the buffer then the FPS will drop w/ dual writing. And it will take the longer to write the buffer to the cards (i.e., empty the buffer)
 

privatebydesign

Would you take advice from a cartoons stuffed toy?
Jan 29, 2011
8,167
1,517
119
On my 1DS MkIII's, which also had an SD and CF card slots, I only ever used the SD slot when I was shooting remotely so I could put medium jpegs on it to view remotely. Any other time I found it slowed the camera down too much, which has always been my biggest issue with the notion of a second card slot as a 'backup'. What use is it if it restricts speed and response?

The way Canon almost always implement dual slots (all but the 1DX) is not conducive to using them as a 'backup' strategy so I never do, even the 1DX MkII moved yet again to different capability slots!
 

AlanF

Canon 5DSR II
Aug 16, 2012
6,248
4,146
Mt Spokane Photography said:
SecureGSM said:
oh.. not 500. please :)
I exaggerated, Its probably more like 150,000 write cycles before 10% of them fail, but I'd avoid low level formats until they are needed, such as before a long video.
Is that the same for CF cards?
 

littleB

EOS T7i
Jun 29, 2017
66
15
Russia
I made exactly the same experiment some time ago:
5D mk4, CF 128 GB Sandisk extreme pro (rated 160), and SD expreme pro 64 GB UHS-I.

I do not remember exact results, but approximately sustained frame rates are: like 3.2 fps for single CF, 2.8 single SD, and 2.3-2.4 fps if writing RAW to CF+SD
 
Sep 24, 2012
60
1
www.rudoffphoto.com
Colleagues -- I also use CF + SD in my %d3 & 4 for redundancy. I rarely shoot in bursts of > 8-10. But I was, I admit, alarmed at the statement that low-level formatting of SD will damage it or shorten life. I have long assumed that formatting a card prior to use is better for it, not worse, and hence I always format both CF and SD after I download (and back up) my day's take. But should I avoid low level formatting? Sorry for such a simple question but I'm a pretty simple guy.
 

SecureGSM

2 x 5D IV
Feb 26, 2017
1,626
584
Private with all due respect:

SD tech moved on quite a bit since the 1DS days. in fact 5d III to 5d IV = huge difference in SD card slot throughput. massive difference.

With 5D IV: SD slot is no longer being a serious limitation with 78 shots - 30 seconds of continuous shooting - vs 98 on CF.
therefore, writing to both card simultaneously is a reasonable compromise, trade off in order to protect images. please read on..

with regard to what Mt. Spokane Photography just said and he is very close to the mark. Thank you. I would like to bring this into perspective if I may as I feel that this being an important subject:


I exaggerated, Its probably more like 150,000 write cycles before 10% of them fail, but I'd avoid low level formats until they are needed, such as before a long video
With modern NAND memory - Wear Leveling protection aside as low level format is full rewrite of every single byte of information - expectancy of the life is:

5000 to 10000 cycles (!!!!) ONLY !!!

it used to be up to 100,000 but with modern high density chip architecture and diminished quality due to cost saving race to the bottom, it is now roughly 5000.

Here is the message to naysayers: the chances for the card to fail is dangerously high at 1:5000 for the brand new card. anyone who understand probabilities would not ever risk writing to a single card if what you shoot is valuable or worth a dime at least.




privatebydesign said:
On my 1DS MkIII's, which also had an SD and CF card slots, I only ever used the SD slot when I was shooting remotely so I could put medium jpegs on it to view remotely. Any other time I found it slowed the camera down too much, which has always been my biggest issue with the notion of a second card slot as a 'backup'. What use is it if it restricts speed and response?

The way Canon almost always implement dual slots (all but the 1DX) is not conducive to using them as a 'backup' strategy so I never do, even the 1DX MkII moved yet again to different capability slots!
 

SecureGSM

2 x 5D IV
Feb 26, 2017
1,626
584
you are right on the money, Thank you very much:

that gives you : 96 vs 84 images per 30 seconds continuous shooting . which is almost identical to the 98 vs 78 numbers I evangelised above.

let's look at the lowest numbers: 98 vs 78

CF card slot throughput is only 25% faster than SD card slot throughput on 5D IV.

therefore writing to both cards simultaneously may be considered as a reasonable compromise unless peak performance was required - heavy continuous shooting, high bitrate video, etc.



littleB said:
I made exactly the same experiment some time ago:
5D mk4, CF 128 GB Sandisk extreme pro (rated 160), and SD expreme pro 64 GB UHS-I.

I do not remember exact results, but approximately sustained frame rates are: like 3.2 fps for single CF, 2.8 single SD, and 2.3-2.4 fps if writing RAW to CF+SD
 

privatebydesign

Would you take advice from a cartoons stuffed toy?
Jan 29, 2011
8,167
1,517
119
SecureGSM said:
Private with all due respect:

SD tech moved on quite a bit since the 1DS days. in fact 5d III to 5d IV = huge difference in SD card slot throughput. massive difference.

With 5D IV: SD slot is no longer being a serious limitation with 78 shots - 30 seconds of continuous shooting - vs 98 on CF.
therefore, writing to both card simultaneously is a reasonable compromise, trade off in order to protect images. please read on..
'Reasonable 'is entirely subjective so my actual point stands. Dual slots in all Canon cameras (except the 1DX/1DC) is a compromise, which is what I said and is why I, personally, don't use them unless the situation dictates a different compromise, like tethered shooting where sending RAW files is too slow.

The newer SD card and slot tech is, with respect, irrelevant, it might change the compromise curve for some however knowing how cheap so many people are (the endless wailing about $7.99 a month for Adobe irrespective of the misunderstood 'renting' aspect being a prime example) I would wager most people are using older generation left over SD cards from previous cameras as their 'backup', thereby compromising themselves in speed and reliability.