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Thread: 1Dx: what's the "right" CF card?

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    1Dx: what's the "right" CF card?

    Anyone know how best to determine the "right" speed CF card for the 1Dx? I don't want to buy one with a higher speed rating than what the 1Dx can use (as the price tag tends to skyrocket), but don't want to underbuy either. Our 40x cards feel quite slow; the red light stays lit for a long time after shooting a burst big enough to fill the buffer.

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    I have several Lexar Platinum II 16gb cards that are 200X which are not too expensive and work well.

    I also have Sandisk Extreme Pro 16gb cards which are UDMA 7 90MB/s. These are more expensive than the Lexar and they work well also.

    Both of the above have no trouble shooting full size RAW files in high speed mode

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    Senior Member neuroanatomist's Avatar
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    Quote Originally Posted by Joel Eade View Post
    I also have Sandisk Extreme Pro 16gb cards which are UDMA 7 90MB/s.
    I use a set of three Sandisk Extreme Pro 32 GB 90 MB/s cards. I write RAW simultaneously to both cards, the card on slot 1 gets swapped with the third card, the card in slot 2 stays in the camera as a backup until the files from the other card are on the computer and backed up to two external drive. That way, I never have fewer copies of every image.

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    Super Moderator Kayaker72's Avatar
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    My understanding is that the 1DX is compatible with UDMA 7, which, in theory, allows for transfer of up to 167 MB/sec. The minimum you want, for video at least, is 10 MB/sec for IPB compression or 30 MB/sec for ALL-I. So, in theory, the 1DX should be able to see the full benefit from the new Lexar "1000x" (150 MB/sec) or Sandisk 160 MB/sec cards. I say in theory, as actual transfer rate could be limited and "compatible" just means that it accepts them. BTW, I found a thread where someone claims to have used a Lexar 1000x card and got 30 RAW files before the buffer in the 5DIII filled and the fps slowed. That beat what I get with my Sandisk Extreme Pro 90 MB/sec UDMA 6 card where the buffer fills at 12-13 shots.

    BTW, apparently Sandisk has been selling UDMA 7 cards from 90 MB/sec up to 150 MB/sec. Seems the higher the memory capacity the faster the transfer rate with the 150 MB/sec in the 256 GB cards. So, not all UDMA 7 cards are going to give you 167 MB/sec.
    Last edited by Kayaker72; 10-27-2013 at 01:43 PM.

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    Senior Member Jonathan Huyer's Avatar
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    Yes the 1DX can take full advantage of UDMA7, but so can the 5D3 and even my old 5D2 could use it after a firmware update. I'm a big fan of fast cards, because nothing drives me crazier than having to wait for a buffer to empty when there's a rare animal like a wolf right in front of me. I have used the 100 MB/s card in my 1DX and it is very, very good. I also just picked up a 160 MB/s card and notice a slight improvement (I haven't actually tried counting the burst yet). The speed rating refers to the fastest it will ever do, and my understanding is that real-world performance is always a bit less. So I don't think we can expect a 100 MB/s card to sustain 5 fps with 20 MB files for any significant length of time.

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    Thanks all! I ordered a 60MB/s 16GB card, and I'll follow up with a 90MB/s card and a 160MB/s card soon. I prefer to choose quantity over size, as we have too many cameras these days and having one 128GB card with lots of room on it does little good when four cameras have filled up the last of the cards and now I can only shoot with one camera.

    Similar to neuroanatomist, I have a sheet of paper with five regions marked off: "to be downloaded", "downloaded, hold for verification", "ready to format", "return to service", and "problem, hold for resolution". Cards start on TBD, and after a visit to the computer they return to DHFV. Once the hourly Time Machine job has run, I consider the cards "eligible" to move to RTF if we're low on cards, but otherwise I wait until I've finished my work in Lightroom and have copied the job to the appropriate storage space. Cards in RTF get formatted in a camera and moved to RTS; they get reformatted when they're "assigned" to a camera to be sure the folder names are as-expected.

  8. #8
    Senior Member Jonathan Huyer's Avatar
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    Okay I just conducted a burst test with my 1DX, using my various cards. Here's what I got:

    Sandisk 160 MB/s: 53
    Lexar 1000x: 51
    Sandisk 100 MB/s: 50
    Sandisk 90 MB/s: 48
    Sandisk 60 Mb/s: 45
    Sandisk 45 Mb/s: 42

    (camera set at ISO 100, 1/500 sec with lens wide open, manual focus, raw, maximum burst speed).

    These numbers are all very good, but really they reflect more the huge buffer size of the 1DX as compared to the card speed. The time you really notice the difference in card speed is after the buffer has been filled, and you are still shooting. Then the fast cards allow you to keep on blasting, while the slow cards hold you back dramatically. This was very handy for me when a saw a lynx family this past spring... I took 100 shots in a minute and never had to wait for the card to catch up. So if the big initial burst is all you need, then you don't have to bother with a fast card. But if you're shooting wildlife (or making videos), then the fast cards are well worth it.

  9. #9
    A point to remember is read speed.

    Most overlook this and their download speed suffers from it.

    Many cards have a significantly slower read speed.

    I use 1000X UDMA7 Lexar cards, but skipped the slow read of the 16GB version.

    I purchaseed 2 of the Lexar 32GB 1000X 2 pack due to the nearly the same read & write speeds and better pricing at B&H for the 2 pack.


    Will T.

  10. #10
    Super Moderator Kayaker72's Avatar
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    Just playing with some numbers. The 1DX buffer is listed as 35 shots (wow) with the RAW file size of 23.2 MB. Given that:
    Sandisk 160 MB/s = 53 shots minus buffer of 35 = 18 shots "written" to card beyond buffer. Times this by 23.2 = 417.6 MB. 53/12 fps = 4.41 sec. Write speed 417.6/4.41 sec = 94.6 MB/sec

    Using the same methods to estimate the write speed in a 1DX for the other cards:

    Lexar 1000x: 87.3 MB/sec
    Sandisk 100 MB/sec: 83.5 MB/sec
    Sandisk 90 MB/s: 75 MB/sec
    Sandisk 60 MB/s: 61.9 MB/sec
    Sandisk 45 MB/sec: 46.4 MB/sec

    Then, doing the math on the Lexar 1000x in a 5DIII that I read about, 30 shots taken, 13 shot buffer, 27 MB RAW file size = 91.8 MB/sec. Very similar to the 87.3 MB/sec write speed Jonathan observed. But I am going to retest my 90 MB/sec Sandisk.

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