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GX8 SD Card Speed? Has anyone tested?

Discussion in 'Panasonic Cameras' started by oldracer, May 21, 2016.

  1. oldracer

    oldracer Mu-43 All-Pro

    Oct 1, 2010
    USA
    I bought a GX8 a month or two ago and have just started playing with high speed burst mode. It's great as far as the number of frames in the burst, but after the burst the camera takes a long time to move the photos (JPG + RAW) from the internal buffer to the SDHC card. I am wondering if a faster card would help.

    I am testing using a Toshiba card marked U-1, C-10, and "30 MB/s." The 30MB/s should permit a U-3 marking, so I don't know why I have the U-1. (Speed Class - SD Association)

    So ... have any GX8 owners done testing to find the point where a faster card does no good? And, what is that point?

    (Please do not clutter up the thread with speculation if you are not a GX8 owner and have not done any testing.)
     
    Last edited: May 21, 2016
  2. specialagenttuna

    specialagenttuna Mu-43 Regular

    34
    Apr 19, 2013
    I'll try it out tomorrow though I never shoot jpg+raw. Seems pointless since every pic can use a tweak IMO. I don't use any cards slower than 95MB/s though I have some 45's that I'll test with. How many can you shoot before the buffer is filled?

    Sent from my SAMSUNG-SM-N910A using Tapatalk
     
  3. oldracer

    oldracer Mu-43 All-Pro

    Oct 1, 2010
    USA
    Thanks very much. That is generous.

    Testing this morning on "H" mode, writing JPG and RAW, mechanical shutter:

    With the lens pointed at my desk and nothing to focus on, both AFS and AFC modes, I get 32 photos in 11 seconds and writing to the buffer take 89 seconds from the first "click."

    With the lens pointed so there is something to focus on, AFS mode, I get 32 photos in 8 seconds and writing takes the same 89 or 90 seconds.

    Shooting hi-res JPG only (aka "fine") I got 160 shots in 45 seconds before I released the shutter button. Writing took 98 seconds. So in this case the smaller images were still going into the buffer faster than they were being written to the card, but the buffer was large enough for any shooting that I can conceive.

    A little disappointing, though, that none of the tests produced the 6-8 frames/second that Panny advertises. Only about half. The manual specifies the burst rate number ar "When recording is performed under the test conditions specified by Panasonic." But the test conditions are not specified. The bold print giveth and the fine print taketh away.

    Edit: 14-140mm MK II lens, if that matters.
     
  4. Phocal

    Phocal Mu-43 Hall of Famer

    Jan 3, 2014
    • Appreciate Appreciate x 1
  5. specialagenttuna

    specialagenttuna Mu-43 Regular

    34
    Apr 19, 2013
    I tested it with both a 45 and 95MB/s card. I get 32 shots no problem and I can preview them in about the same time but the buffer definitely climbs back to 32 a lot quicker (as expected) on the faster card. How did you determine when it was done writing? Did you just wait until the buffer maxed out again?

    Sent from my Nexus 6P using Tapatalk
     
  6. oldracer

    oldracer Mu-43 All-Pro

    Oct 1, 2010
    USA
    I timed from the point where I first pressed the shutter to the point where the red "writing" light (LCD left side upper) went out. (aka "access indication" manual pg 33 "About the card" section) While I was holding the shutter button the shots fired regularly until the 11 second point, at which time there was a hesitation so I released the button. From that point it was another 79 seconds or so until the red light went out.

    In the past when I have tested like this, the camera usually ran out of write speed before the card did. When that happens a faster card gives no improvement.
     
  7. specialagenttuna

    specialagenttuna Mu-43 Regular

    34
    Apr 19, 2013
    Ah I missed that icon. I normally don't shoot in burst (but if I do, I do the 4k shot) so I never really see it. Thanks!

    Sent from my Nexus 6P using Tapatalk
     
  8. oldracer

    oldracer Mu-43 All-Pro

    Oct 1, 2010
    USA
    OK. Based on your info, I ordered a 16GB Sandisk SD "Extreme Pro" card which claims 90MB/s write rate.

    Definite improvement: 34 shots in 6 seconds, so a few more shots at a 25% faster frame rate. The buffer finished emptying in 40 seconds, better than a 2X improvement in speed.

    I guess I'd better upgrade my SD cards!