How raw is RAW format?

Discussion in 'Digital Photography' started by Editor, Dec 21, 2003.

  1. Does anyone have a(n exhaustive) list of what features are done after RAW
    images are taken and therefore adjustable with the RAW files?
    I can think of the following: white balance, exposure compensation, in
    addition to the effects like B&W, sepia, etc.

    I'd much appreciate if someone can give a clear explanation for why certain
    things are NOT adjustable (ISO, shutter speed, etc.) Thanks.
    Editor, Dec 21, 2003
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  2. Sharpening, saturation, contrast.
    Shutter speed is not, since shutter speed determines the time
    light can hit the CCD/CMOS. You can not determine what happened
    after the shutter closed from historic data.

    Same goes for aperture. Determine the physical size of the hole that
    light will pass through.

    Usually when changing ISO, the aperture/shutter will be adjusted
    accordingly. So you can't change the ISO afterward, but you can use
    levels to regain some of the 12-bit info that can't fit into 8 bit
    of JPEG. Seen an example where details burned out in highlight could
    be saved from RAW.
    Povl H. Pedersen, Dec 21, 2003
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  3. Editor

    Mark Johnson Guest

    But the speed and shutter are what put the photons on your
    charged-coupled device. And that's basically your RAW. TIFF is
    post-processed, typically. So it's not really what the camera sees.
    RAW should be.

    The advantage of RAW, apart from the smaller file size compared to
    TIFF, is that you can salvage difficult shots, with a wide tonal
    range. You can go into PS and select highlights and shadow separately.
    And you might avoid blowing out highlights or dropping shadows, which
    might happen if you allowed the firmware to generate a TIFF or JPG.

    RAW just allows you to make a better photo with what the CCD sees,
    Mark Johnson, Dec 21, 2003
  4. Editor

    bmoag Guest

    Raw is what actually comes off the CCD before the computer applies an
    algorithm to create color gamuts and saturations that the sensor actually is
    insensitive to but are assumed to be there in the original.
    bmoag, Dec 21, 2003
  5. Depends on the camera.
    The ISO is adjustable in the raw conversion utility for my Fuji S2.
    (See, I told you it depends on the camera).

    RAW format isn't always just the output of the CCD cells. This may be
    a Fuji-specifc weirdness, but my RAW format is a rectangular grid at
    12mp, not the diamond grid at 6mp that's actually there. Too bad,
    because it makes the file twice as big.
    David Dyer-Bennet, Dec 22, 2003
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