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Choose your ISO wisely: GH2

Discussion in 'Panasonic Cameras' started by sprinke, May 25, 2011.

  1. sprinke

    sprinke Mu-43 All-Pro

    Apr 5, 2011
    Pasadena, CA
    Debi
    These may have been posted here already in different threads, but I thought I'd put them out there again, because I think it's worth knowing!

    Summary: The best ISO's (least noise) on the GH2 are the multiples of 160, as well as 1250.

    [ame=http://www.vimeo.com/18580410]GH2 ISOs to Avoid...and a bonus GH2 short on Vimeo[/ame]

    Panasonic Lumix GH2 noise tests

    Happy shooting!
     
    • Like Like x 5
  2. tomrock

    tomrock Mu-43 Regular

    132
    Jun 21, 2010
    Indianapolis, IN
    That is good to know. Thanks for posting.

    I like your video.
     
  3. m43_user

    m43_user Mu-43 Regular

    143
    Aug 4, 2010
    I assume this only applies to video?
     
  4. sprinke

    sprinke Mu-43 All-Pro

    Apr 5, 2011
    Pasadena, CA
    Debi
    Not mine! :biggrin:
     
  5. sprinke

    sprinke Mu-43 All-Pro

    Apr 5, 2011
    Pasadena, CA
    Debi
    Check the second hyperlink, below the video. Those are stills results.
     
  6. flash

    flash Mu-43 Hall of Famer

    Apr 29, 2010
    1 hour from Sydney Australia.
    Gordon
    I would think this applies to stills as well. There was a test done some time ago on some Canon models that came to the same conclusion. Multiples of the true base ISO were the cleanest. In one case the intermediate ISOs were fake. So if you shot at ISO 250, the camera actually shot at ISO 200 and pushed the file, even RAW, with software.

    I have only ever shot at multiples of the base ISO eve since then.

    Gordon
     
  7. crsnydertx

    crsnydertx Mu-43 Top Veteran

    995
    Dec 31, 2010
    Houston, TX
    Chuck
    Kinda throws a wet blanket over Auto ISO, doesn't it?
     
  8. flash

    flash Mu-43 Hall of Famer

    Apr 29, 2010
    1 hour from Sydney Australia.
    Gordon
    Yep. Sure does. I never use auto ISO as a result of this. Then again maybe cameras choose whole stop increments. Might need to look at this.

    Gordon
     
  9. Tom Swaman

    Tom Swaman Mu-43 Veteran

    Speaking of wet blankets, what about the impact of using exposure compensation on noise generation. I try to always shooot using histograms and luminance control. Rarely do I shoot available light much below a base ISO +1/3 stop. if I am shooting a very dark object against a lighter background, I oftyen over expose by 1 1/3 to 1 2/3 stop. I tend to do this using preset exposure compensation and not by opening my lens aperture.

    So, anyone care to comment on which deteriorates the image worse, the noise at higher ISO values and/or at mid-multiples of ISO 160 or a less than optimum exposure? I for one would enjoy reading your comments and learning.

    Thanks,
    Tom
     
    • Like Like x 1
  10. Tom Swaman

    Tom Swaman Mu-43 Veteran

    Sprinke,

    What do you think. My comment is both serious and a serious question?

    Thanks,
    Tom
     
  11. sprinke

    sprinke Mu-43 All-Pro

    Apr 5, 2011
    Pasadena, CA
    Debi
    Hmm, I haven't experimented, but I was under the impression that dialing in "exposure compensation" was primarily changing shutter speed. Perhaps it depends on what mode one is using? For example, in A mode it might change shutter speed, while in S mode it might change aperture?
     
  12. benjie

    benjie Mu-43 Regular

    63
    May 17, 2010
    London
    Would this also apply to the GH1, and for that matter the other G models?
     
  13. Ned

    Ned Mu-43 Legend

    Jul 18, 2010
    Alberta, Canada
    That depends on how high you're going, Tom. At the lower ISOs the performance is going to be much better at full stops than any intermediate levels. For instance, ISO 400 will probably be better than ISO 250. However, when you start getting into higher ISOs, then tuning it down a bit may help even if you're going into 1/3 stops. ie, ISO 2000 may end up being better than ISO 3200.

    As a general rule though, I never use anything but full stops unless I'm using Auto ISO, and the only time I would use Auto ISO is in Shutter Priority mode. Shutter Priority with Auto ISO requires intermediate stops to fine tune that exposure just perfect, so it's a necessary evil in that case. I turn off 1/3 ISO values on my camera though, so that it only displays full stop values when I manually choose ISO.
     
  14. Tom Swaman

    Tom Swaman Mu-43 Veteran

    Sprinke,

    I believe that dialing in exposure compensation is a direct bias on the ISO setting, but I could be wrong. I really believe this to be a real issue that can impact IQ.

    Best regards,
    Tom
     
  15. sprinke

    sprinke Mu-43 All-Pro

    Apr 5, 2011
    Pasadena, CA
    Debi
    How do you do that (on which camera)?
     
  16. Tom Swaman

    Tom Swaman Mu-43 Veteran

    Ned,

    I am confused by what you wrote/mean. To me, a full stop is ISO 320 or 640. I do not understand your 250 and 400 analogy. Thanks in advance for your clarification.

    Best regards,
    Tom
     
  17. zpierce

    zpierce Super Moderator

    661
    Sep 26, 2010
    Minneapolis, MN
    Zach
    I don't believe that's true. I believe what was said earlier is true, at least it's what I've observed from my GH2. If you're in Aperture priority, it adjusts the shutter speed, if shutter priority, then it adjusts the aperture. If the shutter speed gets below a certain point (which is determined by your focal length) in any mode the ISO will adjust if set to auto.
     
  18. I initially experimented using full-stop ISO increments a while back because it was a pain to change it quickly using 1/3 stops. When I first heard about this issue I never went back to using the smaller increments, be it Canon, Olympus, Panasonic...

    Given this I don't see much need for such small ISO increments. The camera already has two fine-tunable exposure related variables (aperture and shutter speed).
     
  19. zpierce

    zpierce Super Moderator

    661
    Sep 26, 2010
    Minneapolis, MN
    Zach
    Huh... I just looked at the stills link, and I don't see the results that were so clear in the video at all. In fact ISO 200 looks much better than 160?? Especially in the set labeled "Next: the whole frame at all iso settings"

    Am I missing something here?
     
  20. flash

    flash Mu-43 Hall of Famer

    Apr 29, 2010
    1 hour from Sydney Australia.
    Gordon
    Exposure compensation usually effects either aperture or shutter speed based on what mode you're in. With some cameras if you set auto ISO then it *may* come into play in exposure compensation, but it won't if you use manual ISO.

    In the *bad old days* I used to check every new camera and meter accordingly. Cameras with sequential serial numbers could meter differently. i also used to test and compensate for films as well (set Velvia at ISO 40 for example). I still do meter tests on my digital bodies and find differences, but in new ways. For example, the CCD on my new M9 tolerates NO over exposure, like my old 5D2 did. So I have to be careful no to clip as they wont recover. Shadows can be pushed harder though. On my EP-2 it hold highlights a bit better than the reviews indicated, so I expose to the right a bit more to keep the shadows clean.

    The EP-2 i have was tested to have a native ISO of 200. Before the DPReview test everybody thought it was 100. So just cause it's on the camera doesn't mean it is. Test your gear and work out where it's best.

    The G2 I just picked up seems to have a native ISO of either 100 or 200, according to the display. Is it the same sensor as the other Panny's? Are they marked as ISO 160? Now that would be interesting.

    Gordon