Canon G2 and auto-ISO setting -- what rules does it follow?

Discussion in 'Digital Photography' started by John Faughnan, Apr 10, 2004.

  1. I usually set my G2 to ISO 50-100, up to 200 if I'm in marginal light
    conditions (400 is too noisy with this camera).

    There's an auto-ISO setting. I can't figure out rules it applies.
    Logically the camera should look at the flash setting, and then adjust
    ISO to maintain shutter speed > 1/30 sec (for example). It doesn't
    seem to do this.

    OTOH, I think the internal flash works better with auto-ISO
    (presumably camera shoots at ISO 50 then?). That's important, since
    flash exposure with the built-in flash on the G2 is not good.

    Any suggestions?

    john


    PS. I do like the camera quite a bit. I won't replace it until
    Canon/Nikon/SONY offers me 6mpixel, excellent image quality (no
    fringing, etc), ISO 800 with tolerable noise, similar non-SLR form
    factor with the "flippable" viewer, JPEG2000 on camera, faster cycle
    time, throughput and recovery time for about $500 US. None of this is
    technically challenging at all ... more a matter of marketing
    decisions ... but of course marketing decisions are much less
    predictable than technology decisions ...

    meta: jfaughnan, jgfaughnan, Canon G2, G3, G1, exposure setting, ASA,
    ISO
     
    John Faughnan, Apr 10, 2004
    #1
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  2. John Faughnan

    Don Guest

    I have a G2 also, and also have never been able to discern the algorithm
    used for auto-ISO. What I have found, though, is that if you shoot RAW,
    it's best to just lock the ISO 50 setting in. The higher ISOs simply boost
    the gain in the electronics prior to (or more likely during) digitizing the
    CCD output. By saving RAW, you preserve the 12-bit depth of data which is
    sufficient to do the same thing in post processing.

    The only drawbacks I've found to that are the larger file sizes compared to
    JPEG, and an apparent increase in the camera's refusing to shoot in low
    light, for which it's notorious anyway, and of course the need for more
    frequent post-processing.. None of these particularly bother me since I use
    two 1GB cards and travel with either a laptop or a digital wallet, and
    normally post-process everything anyway.

    I also feel the way about the camera that you do.

    Don


    "John Faughnan" <> wrote in message
    news:...
    > I usually set my G2 to ISO 50-100, up to 200 if I'm in marginal light
    > conditions (400 is too noisy with this camera).
    >
    > There's an auto-ISO setting. I can't figure out rules it applies.
    > Logically the camera should look at the flash setting, and then adjust
    > ISO to maintain shutter speed > 1/30 sec (for example). It doesn't
    > seem to do this.
    >
    > OTOH, I think the internal flash works better with auto-ISO
    > (presumably camera shoots at ISO 50 then?). That's important, since
    > flash exposure with the built-in flash on the G2 is not good.
    >
    > Any suggestions?
    >
    > john
    >
    >
    > PS. I do like the camera quite a bit. I won't replace it until
    > Canon/Nikon/SONY offers me 6mpixel, excellent image quality (no
    > fringing, etc), ISO 800 with tolerable noise, similar non-SLR form
    > factor with the "flippable" viewer, JPEG2000 on camera, faster cycle
    > time, throughput and recovery time for about $500 US. None of this is
    > technically challenging at all ... more a matter of marketing
    > decisions ... but of course marketing decisions are much less
    > predictable than technology decisions ...
    >
    > meta: jfaughnan, jgfaughnan, Canon G2, G3, G1, exposure setting, ASA,
    > ISO
     
    Don, Apr 10, 2004
    #2
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  3. "Don" <> wrote in message news:<>...
    > I have a G2 also, and also have never been able to discern the algorithm
    > used for auto-ISO. What I have found, though, is that if you shoot RAW,
    > it's best to just lock the ISO 50 setting in. The higher ISOs simply boost
    > the gain in the electronics prior to (or more likely during) digitizing the
    > CCD output. By saving RAW, you preserve the 12-bit depth of data which is
    > sufficient to do the same thing in post processing.


    Ahh, that's verry interesting. It explains a lot. RAW is too much
    post-processing work for me, but this emphasizes again why it's the
    way to go for higher level photography.

    What digital wallet do you use? I normally travel with my iBook, but
    I've thought about buying a dig wallet as well. (Too bad the iPod
    doesn't do a better job of this -- that was my biggest iPod
    disappointment).

    Great to know there's another G2 fan out there who wants the same
    replacement camera I'm hoping for ... 6mpixel, excellent image
    quality (no fringing, etc), ISO 800 with tolerable noise, similar
    non-SLR form factor with the "flippable" viewer, JPEG2000 on camera,
    faster cycle time, throughput and recovery time for about $500 US.

    john


    meta: jfaughnan, jgfaughnan, Canon G2, G3, G1, exposure setting, ASA,
    ISO
     
    John Faughnan, Apr 11, 2004
    #3
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