Auto ISO in Canon SD and Powershots is not really Auto?

Discussion in 'Digital Photography' started by Sam, Nov 6, 2006.

  1. Sam

    Sam Guest

    I am curious. I have the Canon A80 and I have borrowed the Canon SD 700
    recently. I noticed that when the camera's ISO setting is set to Auto,
    Auto really means ISO 50 while with a friends Sony M1, the ISO does
    change in Auto mode as necessary.

    What's up with that? Is this unique to Canon cameras only?
     
    Sam, Nov 6, 2006
    #1
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  2. It will depend on what mode you use, I suspect. On most cameras I have
    owned, the ISO only changed automatically (and within a limited range
    anyway) in some modes, and was locked in the others. Other
    factors/settings may also lock it - eg having the flash set to auto.

    RTM. It should explain what it does in various modes, and when/if the
    ISO really does change automatically.
     
    mark.thomas.7, Nov 6, 2006
    #2
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  3. Sam

    Monkee Guest

    Have you tried using it in a poorly lit room with no flash? I'm pretty sure
    it will ramp itself up to a higher iso in that scenario.
     
    Monkee, Nov 6, 2006
    #3
  4. Also, when flash is on but the flash isn't strong enough to properly
    expose the subject at ISO 50, the camera effectively raises the ISO to
    at least 100. I noticed this on a S410, comparing the "auto ISO" shots
    to a pair of shots at ISO 50 and ISO 100.

    The problem is that you actually have to take multiple shots and
    compare them to see what the camera did - the EXIF info just says
    "auto" in auto-ISO mode, giving you no clue what the camera-set ISO
    actually was.

    Dave
     
    Dave Martindale, Nov 6, 2006
    #4
  5. Sam

    Sam Guest

    :
    : : >I am curious. I have the Canon A80 and I have borrowed the Canon SD
    700
    : > recently. I noticed that when the camera's ISO setting is set to
    Auto,
    : > Auto really means ISO 50 while with a friends Sony M1, the ISO does
    : > change in Auto mode as necessary.
    : >
    : > What's up with that? Is this unique to Canon cameras only?
    :
    : Have you tried using it in a poorly lit room with no flash? I'm pretty
    sure
    : it will ramp itself up to a higher iso in that scenario.

    In Auto mode, it stayed at default ISO 50 ( presume): 1/8 sec @ 2.8,
    while in Program mode, the it was 1 second @2.8. EXIF doesn't show my
    ISO speed while in Auto. :-(

    One would think that Auto would be more sensitive to ISO changes?
     
    Sam, Nov 9, 2006
    #5
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