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320/640 bug fix. GH2 users liking 320 and 640 please look.
  • I may have missed this in another thread, but if I did, so may some of you as well, so I thought I'd report some findings. We all know about the 320/640 noise bug and fix with the GH2. This is not a repeat of that issue but rather a new attempt to deal consistently with the issue.

    I love the look of 320ISO on the GH2 but I have been bitten my the 320 noise bug many times in the past, even when trying diligently to use the 320 fix (going down from a higher ISO). This has caused me to wonder at times whether there might be other issues that effect the issue like shutter speed, or mode (cinema, smooth, etc)… in short, I've been frustrated.

    Well I think I've finally sussed it out. Yes, the 320 (and 640) bug fix does work from a higher ISO - BUT only in you come down from the higher ISO avoiding 1250 and 640 ISO! If you start at 800 ISO, click to 640 ISO and then to 320 the noise will appear as if you started the camera from 320. If you start at 800 and click to 400 and then to 320 the noise is controlled as it should be. Same with 1600 to 1250 to 640 to 320 (noise), as opposed to 1600 to 800 to 400 to 320 (clean).

    I believe this may be the culprit for some of the anomalous findings people have come up with in previous noise tests and who 320 has been poo-pooed at times as out of control noisy.

    I could post examples here, but I don't think it's needed. Those of you wanting to use 320 and having issues can try this yourselves easily to check my findings. I've tested this now in a number of controlled tests and I'm getting 100% clean results now with 320 as long as I avoid 1250 and 640 when coming down from the higher ISOs.

    Yes, it's irritating having to do this to begin with, but it's still a MUCH faster start then our RED, and in fact, to my eye 320 is the sweet spot for noise/color on this little miracle camera, so I'm pleased to have a consistent fix for the issue.

  • 72 Replies sorted by
  • i can confirm this.
    i also noted this, when i go down in iso with the quik menu button, there is more noise, then when i go down throe the quick menu touch screen menu.

  • Wild, thanks for posting your results. So it seems it's best to stay in the middle of the ISO menu as long as possible before reaching your destination ;)

  • Very cool, Cosimo. Thanks for digging into this. Perhaps the positive way to think about it is to always come down from the next highest setting; ie. 400 to 320, and 800 to 640. Yes?

  • Right, navigate horizontally across the center row of standard ISO's (200, 400, 800...) and then click up to select 160, 320, 640... The bottom row is always noiser than the center or top row.

  • @cosimo_bullo, it's already been established that the best practice is to come down from the ISO setting 1/3 stop higher.

  • No, balazer, you made in error before, I believe, when you wrote:

    "Switching to ISO 320: low noise from 400, 500, or 640; high noise from all others and from power off"

    In fact, going to 320 from 640 is just as noisy as starting from 320. This is the new information and people need to/should know about it. Please test yourself and you'll see what I'm talking about.

    This is why there has been so much confusion re. 320, and this is why I did this as a new thread.

  • Yes, it seems that going from 640 to 320, it depends on where you were before 640. 320 -> 640 -> 320: low noise. 1250 -> 640 -> 320: high noise. That's something I didn't discover in my original testing.

    But regardless, the rule we came up with was to come down from the setting 1/3 stop higher.

    You didn't need to start a new topic just to add a small piece of new information. There's something to be said for keeping all of the relevant information in the same place, where people may have already subscribed to the topic.

  • This is important, new information. Maybe it should go in the original post, but it needs to get some "bump"

  • Already done, DrDave.

  • There's no reason to be so defensive. We are working towards the same goal. This is brand-new information that was not included in your initial report.

    If this saves one GH2 user on a paying job from having the 320 bug than it's worth having posted in a new thread

  • I'm not being defensive. I'm offended by people who think every little idea deserves its own topic, and don't bother to use the existing topics.

  • I'm glad this was given it's own topic. Had it been posted in the old "320/640iso Noise" thread, then I probably wouldn't have looked at it. By creating a new thread, it emphasizes the importance of the information. Thanks cosimo_bullo for your additional tests. Thanks balazer for your initial testing.

  • it is much more clear now, and better to understand for me then the 1/3 stop higher. (i was thinking overexposure instead off iso

  • Definitely glad it has its own topic. Now I know to do exactly what Cos says to use 320, because just going down from 640-320 was what I did and it's damned good to know 320 can be cleaner.

    Now I just want to know if going from 800 to 640 is the right way to go for clean 640.

  • +1 for the new topic. It's the fullest and clearest explanation so far of how to avoid ISO bug issues.

  • Kholi - yes on 800 to 640 as per what we've seen in our tests.

  • How do you set the camera up to start on a specific ISO by chance?

  • @kholi, just the custom settings C1, C2 and C3. If you save a certain ISO on those settings, it always defaults to that ISO when you switch to the custom mode

  • Thanks. That's how I've been doing it too.

  • " just the custom settings C1, C2 and C3" Does this avoid the Iso bug, or do you suggest to put isos like 800 into it and switch down manually after choosing the preset?

  • No, the C1, C2, C3 buttons don't fix the problem outright. As you suggest, they simply start you in a good position to then safely click down to your desired setting.

  • @cosimo_bullo Thanks for info mate. :-) I will also confirm.

  • @LPowell "Right, navigate horizontally across the center row of standard ISO's (200, 400, 800...) and then click up to select 160, 320, 640... The bottom row is always noiser than the center or top row."

    That is the clearest explanation yet. Thanks.

  • I guess not everyone knows what a stop is. ;) I will update the FAQ to be clearer.

    The bottom row of ISO settings (250, 500, 1000...) is not always noisier than the other rows. 250 is noisier than 320. 500 is noisier than 640. 4000 is noisier than 5000. The others in that row are less noisy or just as noisy as their higher neighbors.

  • some people just won't let it go...