The 5D Mark III & SD Memory Cards

[Canon Rumors]

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From Jeff Cable
Photographer Jeff Cable has posted an article on his blog about some of the speed limititations associated with using SD cards in the new Canon EOS 5D Mark III.

From Jeff

Well…after some testing I have determined that, if you care at all about high speed shooting or clearing you buffer quickly, YOU DO NOT want to put a card in the SD slot. Why? Because, for some reason unbeknownst to me, Canon decided to build the 5D Mark III with one very fast CF slot which supports the newer UDMA7 protocol and a standard SD card slot which does NOT support the high speed standard (called UHS – for Ultra High Speed).

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cr 

[neuroanatomist]

One more thing. Most of the time, this is a hardware limitation and can not be solved with a firmware upgrade. Even more of a disappointment!

From my testing, firmware updates for both the 7D and 5DII dramatically improved the data throughput for 90 MB/s CF cards, so perhaps there's some hope?

Makes me glad the 1D X has dual CF, though...

[ewg963]

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<strong>From Jeff Cable<br />


</strong>Photographer Jeff Cable has posted an article on his blog about some of the speed limititations associated with using SD cards in the new Canon EOS 5D Mark III.</p>
<p><strong>From Jeff</strong></p>
<blockquote><p>Well…after some testing I have determined that, if you care at all about high speed shooting or clearing you buffer quickly, YOU DO NOT want to put a card in the SD slot. Why? Because, for some reason unbeknownst to me, Canon decided to build the 5D Mark III with one very fast CF slot which supports the newer UDMA7 protocol and a standard SD card slot which does NOT support the high speed standard (called UHS – for Ultra High Speed).</p></blockquote>
<p><a href="http://jeffcable.blogspot.co.uk/2012/06/why-you-should-not-put-sd-card-in-your.html" target="_blank"><strong>Read More</strong></a></p>
<p><strong><span style="color: #ff0000;">c</span>r </strong></p>

Another Canon disappointment period!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

[spinworkxroy]

Yea, the SD slot in the mk3 is dissapointing…sometimes i think it's even slower than my 60D!
However, at least there's a workaround…
I rarely use burst mode and i usually shoot mRaw in my CF card and mJpg in my SD card only and in the event i really need ALOT of burst photos, i just remove the SD card and use only the CF…but that's rare…
For MJpg, the burst mode works well enough for me even with the SD…i almost never shoot full size anyways so…it's ok for me.

[bornshooter]

well this doesn't matter for wedding photographers unless you are a machine gunner who likes to spray and pray lol

[TrumpetPower!]

There's no need to actually remove the card. Just set the camera to auto-switch. You get full performance while it's using compact flash. If you're not paying attention and let the CF card fill up, rather than the camera simply stop shooting altogether, you get the degraded performance of the SD card which is a whole hell of a lot better than nothing. Pop in another CF card and you're good to go.

While the performance of the SD slot is likely hardware-limited, there are software-related performance enhancements that Canon could readily enough implement. You're screwed when writing the same format to each, but there's no non-software reason why RAW on the CF and a smaller format on the SD shouldn't work fine. Canon has taken the understandable, easy approach of making the two pathways working identically, but they should be able to re-jigger things so that it writes RAW to CF at its full speed and JPEG to SD at its full speed, which would probably mean the SD would clear out even faster than the RAW.

I'm not suggesting that kind of code is easy to write, but it *is* what their engineers get paid to do, and it's the sort of challenge that's likely to get one or more of them excited to come to work in the morning.

Cheers,

b&

[sanj]

If this is true, its disgusting...!

[mememe]

Guys i can tell u why canon did this... Cause SD-Cars SUCK.

[billiam]

Recently a friend ask me why buy CF card while SDs are so much cheaper and the "spend" is faster. Then I did some research on this topic. I'm a CF card believer so I found a test was done by Rob Galbraith on memory card writing tests(link is for 5D Mk3). He has done few testing for many difference camera with lots of difference brand and speed cards.

http://www.robgalbraith.com/bins/camera_wb_multi_page.asp?cid=6007-12452

[ablearcher]

USB 2.0 and SD without UHS in a pro body in 2012 with a ridiculous price tag...  WTF Canon?

[neuroanatomist]

There's no need to actually remove the card. Just set the camera to auto-switch. You get full performance while it's using compact flash.

I know that's the theory, but have you tested this personally?  Thanks!

[Drizzt321]

USB 2.0 and SD without UHS in a pro body in 2012 with a ridiculous price tag...  WTF Canon?

The USB 2.0 is disappointing, but it's probably something baked into the Digic V+ which development, taping out, etc was probably started 2-4 years ago before USB 3.0 really started to become popular.

SD w/out UHS, well, that just pisses me off. If they can put it on the t4i (specs taken from here), they should have damn well put it on the 5d3.

[TrumpetPower!]

There's no need to actually remove the card. Just set the camera to auto-switch. You get full performance while it's using compact flash.

I know that's the theory, but have you tested this personally?  Thanks!

One of the first things I did when I got the camera was play around with those settings. I *really* like the idea of recording RAW to two cards, even though I've yet to lose even a single frame to a bad card. Nice idea, except that the buffer gets reeeeeeeeally shallow and painfully slow when it fills up. The original Digital Rebel might actually outperform the 5DIII with dual RAW recording. At least, it feels that way.

I eventually settled on the auto-switch setting. If there's a difference in performance between that and no SD card in the camera at all, I certainly haven't noticed it. Of course, once the CF card does fill up, then you're back to shallow, slow, painful buffer...but only until you pop back in a fresh CF card. And, as I originally wrote, shallow and slow is way better than a brick....

I did use dual RAW when I shot the annular eclipse over the Grand Canyon. I knew I wasn't going to fill up the buffer, even with several-step brackets. Other than that sort of thing, the only practical use I can think of for dual recording would be with an EyeFi card...and, nifty as that thing seems, I personally can't think of any situation where I'd actually use one.

b&

[Dylan]

Does this have any effect with shooting video? I bought sandisk 16gb class 10 45mbs cards and haven't tested the 30 min record time.  Anyone have any failures? And am I safer with CF?

[tt]

There's no need to actually remove the card. Just set the camera to auto-switch. You get full performance while it's using compact flash.

I know that's the theory, but have you tested this personally?  Thanks!

With both cards in, set to autoswitch, set to record to the CF card, I got >24 RAW pictures in a burst till it went to the slower frames per second speed. With just a CF card in the camera, there wasn't a difference.
Am I missing something?

Sounds like Jeff's talking about recording to both cards at the same time - which on p117 or so in the manual clearly states will "decrease greatly" the maximum burst.

The camera defaults to the slowest card - but only if you have that card select to record onto, or you're recording to both cards.

To be more accurate with the headline:

Why you can leave an SD card in your Canon 5D Mark III, but if you care about speed, don't record to it if you can, and be aware that recording to both cards simultaneously decreases greatly your maximum burst available