newbie question on ASA speed settings

Discussion in 'Digital SLR' started by bill a, Feb 6, 2005.

  1. bill a

    bill a Guest

    On a Canon D30, for instance, I'm trying to understand what the ASA speed
    settings
    really do. Is there anything optically/electronically different about the
    way the data is
    recorded, or is this simply a parameter for influencing the various
    automation modes?

    thanks
    bill
     
    bill a, Feb 6, 2005
    #1
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  2. bill a

    dylan Guest

    it's an amplifier to boost the signal, higher ISO (ASA) the more the gain,
    and also the noise.
     
    dylan, Feb 6, 2005
    #2
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  3. bill a

    bill a Guest

    so the noise is the (no free lunch) tradeoff like grain size for film.
    that explains it.
    thanks,
    bill
     
    bill a, Feb 6, 2005
    #3
  4. bill a

    Steven Wandy Guest

    so the noise is the (no free lunch) tradeoff like grain size for film.
    Exactly. It's like using a film with faster speed. More grain.
     
    Steven Wandy, Feb 6, 2005
    #4
  5. bill a

    Alan Browne- Guest


    There's no free lunch, but it's not as bad a film grain though.

    Film grain looks noisier (z) and is larger (x,y) as the ISO goes up.

    Digital noise does not get larger in x,y as it is constrained to its
    fixed pixel size. The noise in digital is in amplitude (z) only.

    Hence digital usually looks cleaner than film as ISO goes up.

    Cheers,
    Alan
     
    Alan Browne-, Feb 6, 2005
    #5
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