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GH2 ISO noise bug at 320, 640, and 1250
  • 62 Replies sorted by
  • Vitaliy_KiselevVitaliy_Kiselev
    I think it is not the bug, just camera wants to reduce number of actual amplifier changes.
    So, it depends on direction of ISO increase and your current ISO.
    If it thinks that it can make things work without actual amplification change, just by shifting RAW, it is doing so.
    This is my understanding of this behaviour.
  • alcomposeralcomposer
    @balazer "Simple raw processing" can mean anything. I would say that considering the bug - somehow the correct mode is not 'locking in' - could even be lower bit rate from the original 12bit samples...

    Suffice to say that @VK is probably the only one who knows the code enough to work this one out...
  • balazerbalazer
    Vitaliy, are you suggesting that this bug is simply disabling some NR rather than misconfiguring the sensor? I'm not convinced either way. If that were the case, then this would actually be desirable behavior for those who prefer to have the camera do as little NR as possible, and then do NR after the fact in software.

    To my eyes, at least, I see no evidence of excessive NR at -2.
  • cosimo_bullocosimo_bullo
    That is a very clever workaround to the issue. Good idea.
  • ShaveblogShaveblog
    My simple fix has been to bake in 1600 as the default ISO for my C1/C2/C3 modes, so when I turn the camera on or switch to a different mode I'm forced to turn ISO down. Takes one more thing off the to-do list.
  • balazerbalazer
    I just tested power cycling: powering the camera on in 320, 640, or 1250 ISO causes the bug, regardless of what ISO setting you had previously.

    For anyone interested in testing this himself or herself, it's pretty easy: turn on ETC and 4x zoom, defocus the lens, and adjust the exposure until you see lots of noise on the LCD. Then start switching between different ISO settings. You can use the touchscreen to switch between any two ISO settings.

    And do note that the bug happens when switching from 2500 to 1250. So it's not sufficient to simply switch from higher to lower by adjacency in the on-screen ISO menu. A correct rule would be to switch from the next highest increment by number, e.g. 1600 to 1250.
  • cosimo_bullocosimo_bullo
    I don't believe cycling helps. No, each user seriously needs a sticky on the camera with the reminder to got from high ISO to low. You know how it gets when you're running and gunning... I haven't noticed this at 640/1250 (we rarely shoot high ISO), but at 320, indeed, it's a shot wrecker... has happened to us too.
  • alcomposeralcomposer
    @balazer and everyone...
    Does cycling the power fix this issue? (As in set to an iso- then cycle- no noise?)

    Cheers,
    Alex
  • fatpigfatpig
    omg, panny HAS to fix this. i had the high noise on a night shoot on 320. it ruined my shot...
  • tonalttonalt
    Just to be sure, would it be safe to switch to ISO levels through ISO 160?
  • Vitaliy_KiselevVitaliy_Kiselev
    It is just too smart, and some switches result in simple RAW processing.
  • bwhitzbwhitz
    yea, I just noticed this a week ago... super weird. I wonder what's going in that camera to cause this... ???

    Thanks for the tip on 640 and 1250... ;)
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