Design fault in the 5D3?

[yakim_peled1]

<p><a href="http://jeffcable.blogspot.co.uk/2012/06/why-you-should-not-put-sd-card-in-your.html">SD card issue</a>. </p>

<p>Happy shooting,<br>

Yakim.</p>

[johnw63]

<p>I don't think is a design fault. When you are writing to BOTH cards at the same time, the slower speed card dictates the speed. It sort of makes sense. If you did lots of burst shooting you wouldn't want the CF card getting so far ahead of the SD card that the camera was ALWAYS writing to the SD card. That would slow everything down. It doesn't happen if you shoot only to the CF card.</p>

[alan_bryant1]

<p>John, if you're shooting RAW to the CF and JPEG to the SD, and you wanted neither card to get ahead of the other, the CF card would need to transfer information about five times faster than the SD, since the RAWs are about five times larger. But according to this article, using the SD card will throttle back the CF card. Which means this is a problem.</p>

<p>However, if I'm reading the article correctly, having an SD card in the camera throttles back the CF card *even if the SD card is not being used at all*. I have some old, very slow SD cards, so I can give this a test later. If that is accurate, I would count it as a design flaw, or at least as something that ought to be made clear in the documentation.</p>

[yakim_peled1]

<blockquote>

<p>However, if I'm reading the article correctly, having an SD card in the camera throttles back the CF card *even if the SD card is not being used at all*.</p>

</blockquote>

<p>You are reading it correctly. What's more even if you use a fast UHS card (much faster than 133X) it wouldn't matter. The camera will still default to 133X speed for <em><strong>both</strong></em> cards. </p>

<p>Happy shooting,<br>

Yakim. </p>

[eric merrill]

<p>Have there been any other experiments on this? All I can find is the one photographer reporting this, and I couldn't find where he published data to back up his conclusions. Just because it's on the internet doesn't make it true, even if everybody quotes the same original source. :)</p>

<p>I'd be interested in seeing stats on how many shots can be taken and time to clear the buffer for having the SD slot empty vs occupied but unused. I wouldn't make the immediate conclusion that both slots are slowed down if the SD slot is occupied.</p>

<p>I'm wondering what the real world effect on buffer clearing speed is if you store RAW to the CF and jpeg to the SD. I use a much slower SD card in a 1D4, and it barely affects the buffer clearing speed. After all, the jpeg files are many times smaller. </p>

<p>Eric</p>

[Marcus Ian]

<p>Gawd... that is a design flaw. I noticed in another review awhile ago, someone complaining about the write speed for SD card in the 5D3... I had initially thought that it was just an 'SD card' problem.</p>

<p>Another aspect is that, with very few exceptions, the SD cards don't list an actual (or even a 'x') speed. A new card that is rated 'class 10' could have a write speed from 10mb/s to 100mb/s.</p>

<p>Considering this is one of the 'failings' of the 5D2 (no redundant storage), you would have thought they could have thought it out a bit more. Additionally, the hardware may be incompatible w/ correcting this (subject to the limitations of the memory controller chip) via firmware. That may really suck.</p>

[alan_bryant1]

<p>In a quick test I found no evidence that this is a problem. Gear is a 5D mk III with CF card a SanDisk Extreme 32 Gb UDMA 60 Mb/s. I shot two 12 frame bursts at 6 fps, recording nothing but RAW to the CF card. In one test I had only the CF card in the camera, in the other test I also loaded a very old 1 Gb Toshiba SD card. It has no speed marked but it can't be very fast.</p>

<p>In both cases, clearing the buffer after the 12 frame burst took 5 seconds. This was measured by watching the card-in-use light.</p>

<p>To verify that the SD card is indeed slow, I shot another test in my usual mode, RAW to CF and JPEG to SD. This time the buffer filled at only 7 frames (shooting RAW+L kills the buffer performance, independent of card settings) and flushing the buffer took 12 seconds.</p>

<p>Final test, flipped it to JPEG to CF, RAW to SD. Again I got 7 frames before it halted, and it took 32 seconds to clear the buffer.</p>

<p>Extrapolating from 32 seconds to write 7 RAW to the SD card, writing 12 RAW would have taken about 55 seconds. But I saw writing 12 RAW to the CF card took only 5 seconds, whether or not the SD card was installed. So at this point I'm thinking this is less a problem than they are implying. I'd be happy to see evidence to the contrary.</p>

[KenPapai]

<p>I worry about getting the correct shots not some techno geek quadruple redundancy to slow SD cards NON ISSUE......on a $4,000 5D3... sheesh. I think some of you ought to work for Canon QA obviously you know WAY more than them.</p>

<p>YMMV..... Ken</p>

[yakim_peled1]

<blockquote>

<p>Have there been any other experiments on this?</p>

</blockquote>

<p>As I can hazard a guess that your Hebrew is not fluent :-) let me <a href="http://d-spot.co.il/forum/index.php?showtopic=285892&st=0&p=2191342entry2191342">translate</a>:</p>

<p><em>It certainly disturbed me yesterday [i.e. June 26th - Y.P.]. The CF overflowed and then [the camera - Y.P.] switched to SD. Every 3-4 RAW shots you had to wait for the buffer. Annoying.</em></p>

<p>On another post in the same thread he <a href="http://d-spot.co.il/forum/index.php?showtopic=285892&st=0&p=2191576entry2191576">noted</a> that the card was SanDisk 95Mb/s.</p>

<p>Alan, your experience is very interesting. Thanks for sharing. </p>

<p>Happy shooting,<br /> Yakim.</p>

[Marcus Ian]

<p>I was going to guess that his problem may be related to the specific memory card/ memory card controller combination. Other,similar, problems have shown up before due to the memory card controller chip interface, but I've never seen a Lexar card demonstrate such a problem - that said, this format is a<em> bit</em> more complicated (especially at UDMA7 speeds).</p>

<p>Alan, just curious, how long did it take to clear the buffer in RAW+JPG to only the CF card? (w/ and w/o the sd card)</p>

[dan_south]

Shhh! Quick! Before anybody realizes this, let's all trade in for 1D X bodies!

 

Thanks Alan for running the test and providing the voice of reason.

[yakim_peled1]

<p>Update from Jeff. He later writes:</p>

<p><em>As many of you have pointed out, the degradation in speed will occur when you are attempting to use both the CF and the SD to write files. If you have an SD card in the camera and are not writing to it, you will be fine. I am not sure why you would want that (except for overflow), but this is the case.</em></p>

<p>Happy shooting,<br>

Yakim. </p>

[Marcus Ian]

<p>So the implication is that the 'flaw' is really that the write speed for SD cards is capped at 133x.</p>

<p>If that's the case, (and that seems more consistent) it seems kind of like a ridiculous handicap for the 5D3. - After looking up Rob Galbraith's list of cards, it seems the fastest SD cards (UHS units rated at up to 90+ mb/s) write in the 5D3 at less than 20mb/s - wow.</p>

[jon_austin3]

<p>Well, no camera is perfect, and this is just one more imperfection for the 5D3. Does make you wonder what they were thinking, though. Personally, I would have preferred twin CF cards.</p>