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SD and CF memory cards: camera slot read/write speeds; card selection, marking, and management

ChrisPBacon
Enthusiast

In preparation for adding the Canon EOS 5D Mark IV to our camera stable, I'm reading what information Canon has released or published for its technical support personnel, in addition to data discussed in videos done by Canon, B&H Photo — as might be expected, there are some discrepancies (non-essential, of course) that I've been trying to research.

 

I'm likely going to have the camera write a photo simultaneously to both cards, the risk of losing one much too high. While I doubt that I'll ever be taking/writing photos that rapidly to approach card-write limits, it might pay off to be aware of those limits.

 

Perhaps you know the answers these questions...?

 

1. Has Canon installed the USH-II technology card reader/writer in its cameras since the advent of that technology?

 

2.  An instructor at a Canon Learning Center claims that using a USH-II card in a camera that is equipped with the old USH-I technology actually slows down the read-write process significantly, so much so that it doesn't make economic sense to purchase the very expensive high-rate read-write cards: this seems to be counter-intuitively wrong.

 

3. Watching Canon and B&H videos pertaining to the 5D Mark IV, one briefer said that it's very important that the SD and CF cards are matched as much as possible. Matched for speed?  Matched for capacity?  [Matched for Manufacturer?  Or is there a significant software issue between (old v new; USH-I vs -II) formats, if any?]

 

4. I've never had a SD or CF card fail, though I've found a sector (?) that was unusable.  Have you had any card failures?  If so, what brand was it? What capacity?  What speed?

 

5. Which brand of memory cards (SD and CF) are your favorite?  Any specific reason?  Do you select for card capacity as well as manufacturer?

 

6. Have you seen manufacturers bundle these cards in multiple (3 or more) for SD or CF? SD and CF?

 

7. Months ago, one of these manufacturers switched from having a SD card in a small, plastic, closeable case: the last bunch I purchased, the card was located in a sealed plastic wrapper (no case): ever see a vendor that made a container that would allow you to carry a number of cards (SD and CF, isolated by type)?  Keeping a number of loose memory cards in my camera bag leads to some organization problems, especially now that SanDisk no longer puts these cards in a sealable case.


8. Have you found any useful means of temporarily labeling these cards externallly in order to avoid confusion or mis-identifying?

Chris P. Bacon
F-1; AE-1; EOS 1V, EOS-1D X Mark III, 5D Mk IV, 6D, 6D Mk II, 7D, and 7D Mk II; scads of Canon, Zeiss, and Sigma lenses.
6 REPLIES 6

EOS R supports UHS-II standard.

 

Canon is practically giving the 5D4 away now.  I don't think it will go away any time soon.  There are just too many people with EF glass that aren't going to walk away from their investment.   

 

5D4 - Refurb and new even with C-Log is very affordable, but you will only get UHS-I support.  I'm considering buying one.  This is from the guy who said he'd never buy a new camera that didn't have an articulating screen.  The 5D4 remains king until Canon releases a second gen or 3rd if the RP counts as second gen mirrorless.  The low shot count per battery and RF mount is whats keeping me from going mirrorless. 

 

But thats not what we're here to discuss. 

 

Matched doesn't mean same manufacturer.  It means use cards with as many similar characteristics as possilbe.  This will yeild the most reliable, best overall performance. 

 

I use SanDisk.  I personally have never had a failure.  That said...  All hardware fails.  Even solid state memory (NOR Flash) can eventually develop bad cells. 

 

Bundles, no, just buy what you need.

 

Brand - I select SanDisk based on years of solid performance.  They just work. 

 

My recommendation.  Stick with UHS-I and CF for the your 5D4. 

 

I'm sure others will chime in as well.   

 

 

~Rick
Bay Area - CA


~R5 C (1.0.2.1) ~RF Trinity, ~RF 100~400, +Canon Control Ring

~6D2 (v1.1.1) Retiring ~EF Trinity, others ~DxO PhotoLab Elite ~Windows10/11 Pro ~EVGA RTX 3080Ti FTW3 Ultra ~ImageClass MF644Cdw ~Pixel6 ~CarePaks Are Worth It


@shadowsports wrote:

EOS R supports UHS-II standard.

 

Canon is practically giving the 5D4 away now.  I don't think it will go away any time soon.  There are just too many people with EF glass that aren't going to walk away from their investment.   

 

5D4 - Refurb and new even with C-Log is very affordable, but you will only get UHS-I support.  I'm considering buying one.  This is from the guy who said he'd never buy a new camera that didn't have an articulating screen.  The 5D4 remains king until Canon releases a second gen or 3rd if the RP counts as second gen mirrorless.  The low shot count per battery and RF mount is whats keeping me from going mirrorless. 

 

But thats not what we're here to discuss. 

 

Matched doesn't mean same manufacturer.  It means use cards with as many similar characteristics as possilbe.  This will yeild the most reliable, best overall performance. 

 

I use SanDisk.  I personally have never had a failure.  That said...  All hardware fails.  Even solid state memory (NOR Flash) can eventually develop bad cells. 

 

Bundles, no, just buy what you need.

 

Brand - I select SanDisk based on years of solid performance.  They just work. 

 

My recommendation.  Stick with UHS-I and CF for the your 5D4. 

 

I'm sure others will chime in as well.   

 


My experience with Lexar cards (specifically their Professional series) has been just as good as Rick's has been with SanDisk. You should be fine with either one - IF you buy from a reputable dealer. It is said that counterfeit cards are common.

Bob
Philadelphia, Pennsylvania USA

"Brand - I select SanDisk based on years of solid performance."

 

Over the years I have used all the top brands. "They just work."  I really don't favor one over the other.

EB
EOS 1DX and 1D Mk IV and several lenses!

"Matched:"  I've assumed  that matched pertained to performance, not necessarily manufacturer.

 

Thanks for your response.

Chris P. Bacon
F-1; AE-1; EOS 1V, EOS-1D X Mark III, 5D Mk IV, 6D, 6D Mk II, 7D, and 7D Mk II; scads of Canon, Zeiss, and Sigma lenses.

Peter
Authority
USH-II card in a camera that is equipped with the old USH-I technology slows down on older Canon models. Especially some SanDisk UHS-II cards. There are some benchmarks at the webpage Camera Memory Speed.

Maximum write speed for 5D IV should be: 130 + 90 MB/s (CF+SD). If you shoot raw and save the files to both cards the SD slot will slow down the CF slot. To maintain speed one way is to save raw on CF and jpg on SD. Another way is to only use CF.

Waddizzle
Legend

@ChrisPBacon wrote:

 

2.  An instructor at a Canon Learning Center claims that using a USH-II card in a camera that is equipped with the old USH-I technology actually slows down the read-write process significantly, so much so that it doesn't make economic sense to purchase the very expensive high-rate read-write cards: this seems to be counter-intuitively wrong.

 

3. Watching Canon and B&H videos pertaining to the 5D Mark IV, one briefer said that it's very important that the SD and CF cards are matched as much as possible. Matched for speed?  Matched for capacity?  [Matched for Manufacturer?  Or is there a significant software issue between (old v new; USH-I vs -II) formats, if any?]

 

 


Wikipedia does an excellent job of explaining the differences between the different UHS types.  They even have a chart showing the performance you should expect based upon the UHS rating of the host and card.

 

 

https://en.wikipedia.org/wiki/SD_card 

 

 

In other words, what you have [been] told, [have] watched, and read about is correct.   You will take a performance hit if you put a UHS-II card into a UHS-I slot.  You cannot add horsepower to a car engine by using premium gas, instead of following the manufacturer's recommendation to use regular gas.

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