DSLR Video vs. SD Card Speed Question

Discussion in 'Digital Photography' started by barr08, Mar 27, 2012.

  1. barr08 macrumors 65816

    barr08

    Joined:
    Aug 9, 2006
    Location:
    Boston, MA
    #1
    Hey all,

    I recently purchased my first DSLR (T2i), and had a question about taking 1080p video. The SD card that I have on hand is a Class 4 16GB MicroSD with an SD adapter. My question is - is this card too slow for taking reliable 1080p video? I have heard rumblings that I would want to use at least a Class 6 card or higher, and preferably a Class 10 for the best results.

    My impression is that general quality will increase as the Class of the card increases. Is this a correct assumption? If so, will 1080p video taken on a Class 4 card simply be unusable?

    Does anyone have experience with this? I plan on doing some testing after work, but any advice from this community would be very helpful.

    Thanks!
     
  2. WRP macrumors 6502a

    Joined:
    Jul 20, 2011
    Location:
    Boston
    #2
    The card speed has nothing to do with the quality of video. It will work or it won't work. I had problems with cheap class 6 cards on a t2i. Get a faster card.
     
  3. salacious macrumors 6502a

    Joined:
    May 15, 2011
    #3
    i got a class 10 95mb write speed sandisk 8gb card for £20 which is about $35 good deal for my t3i, or canon 600d whatever its called where you are, i also have a 35mb write speed card class 10 that i got with the camera which also is good, you only get 4 mins to record at a time, but i doubt youl be recording for longer than that.

    you could go lower class, but if i was you stay with class 10, its future proof.. the only problems you could possibly have is video buffering..
     
  4. -hh macrumors 68020

    -hh

    Joined:
    Jul 17, 2001
    Location:
    NJ Highlands, Earth
    #4
    I'd expect that it is probably too slow. The camera's owner's manual should tell you what the minimum is ... I'd expect Class 6.


    No. Basically, the camera's not going to change its video quality based on what kind of card you have - - what happens is that as it tries to stream the data to the card, if the card can't receive it fast enough, you fill up any intermediate buffers and the system "chokes", losing your video stream.

    Depending on what camera make/model/etc, but I'd not be surprised if you could run for a few seconds (maybe even minutes) before the camera's buffer fills and the system chokes and stalls out. Depending on how the camera recovers from that data stream failure, you might end up with a "15 second" clip that's okay, or it could fail to have a close marker and it is just junk. You may as well experiment and try - - probably the worst that can happen is that you corrupt your SD card for which you'll have to wipe & reformat it.


    I have some, but on an entirely different make/model and memory card type. On the Canon 7D dSLR, I've found that if I use a "133x" speed CF card, the 1080p streams okay, but if I trigger for a still photo during the video, it crashes the videostream (but doesn't corrupt it). With a 400x speed CF card, the video's OK and the photo during video is OK ... and the video will resume running after the photo was taken, but with a ~4 second gap of missing video (apparently, from when the still photo was taken). Not quite really what I really wanted ("cake & eat it too"), but better than having the video stream completely shut down.


    -hh
     
  5. barr08 thread starter macrumors 65816

    barr08

    Joined:
    Aug 9, 2006
    Location:
    Boston, MA
    #5
    Thanks guys. This pretty much confirms what I was thinking.
     
  6. barr08 thread starter macrumors 65816

    barr08

    Joined:
    Aug 9, 2006
    Location:
    Boston, MA
    #6
    Just wanted to report back on this - the class 4 card is definitely not sufficient for taking 1080p video on the T2i. It would record for roughly 5 seconds and then stop with some error message.

    I have since purchased a class 10 SDHC card.
     

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