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Histogram - Photography

Hello Whats the use of an histogram? Where can i find info?...

  1. #1

    Default Histogram

    Hello
    Whats the use of an histogram?
    Where can i find info?



    VT Guest

  2. #2

    Default Re: Histogram

    VT wrote:
     


    http://www.luminous-landscape.com/tutorials/understanding-series/understanding-histograms.shtml
    Jim Guest

  3. #3

    Default Re: Histogram


    "VT" <com> wrote in message
    news:%pvRa.5086$ip.pt... 

    A histogram is a two-dimensional graph used for gauging the exposure of a
    photograph. The histogram's x-axis represents the brightness levels capable
    of being recorded by a camera's CCD imager and ranges from zero to a
    camera-dependent maximum value. The y-axis of the histogram records the
    number of pixels present at each brightness level for a given photograph.
    The distribution of brightness levels across the x-axis gives a
    knowledgeable user significant information about over-exposure,
    under-exposure, n highlights, or detail lost to shadow. (Note: I'm
    talking about luminance values only. Individual R,G, and B histograms can
    also provide color balance/color temperature information.)

    The histogram is not a tool to be used thoughtlessly, since in many cases,
    experience is needed to properly interpret a histogram. For example, while
    n highlights are generally considered "bad", sometimes they're
    unavoidable, as in the case of taking a non-flash portrait shot of a person
    against very bright background, since properly exposing for the person's
    face will result in the background being overexposed. In such a situation,
    a photographer might accept the background overexposure if the person's face
    were the only object of interest in the photo, even though a purely
    technical interpretation of the histogram would label the exposure as
    incorrect. Thus, when viewing the histogram for a particular exposure, the
    photographer must also take into account the kind of shooting situation or
    compositional needs he or she is dealing with as the histogram data is
    interpreted.

    In short, the histogram is a great and sometimes nearly indispensable tool,
    provided its use is well understood. You might check out
    www.dpreview.com -- I believe this site has a photo glossary which will
    explain histograms and their use in more detail.

    Finally, you can download a copy of "EXIF Viewer" at
    http://home.pacbell.net/michal_k/exif_v.html, which contains an excellent
    histogram viewer you can use with your existing photos.




    Paul Guest

  4. #4

    Default Re: Histogram

    Jim Townsend <address> wrote:
     
    >
    >
    > http://www.luminous-landscape.com/tutorials/understanding-series/
    > understanding-histograms.shtml[/ref]

    Great article - thanks! Turns out I had misunderstood them when
    explaining them to my wife when she got her new Canon 10D recently. Now
    I gotta eat crow and admit I didn't know what I was talking about...:-)

    --
    - Burt Johnson
    MindStorm, Inc.
    http://www.mindstorm-inc.com/software.html
    Burt Guest

  5. #5

    Default Re: Histogram

    com (Burt Johnson) writes:
     
    > >
    > >
    > > http://www.luminous-landscape.com/tutorials/understanding-series/
    > > understanding-histograms.shtml[/ref]
    >
    > Great article - thanks! Turns out I had misunderstood them when
    > explaining them to my wife when she got her new Canon 10D recently. Now
    > I gotta eat crow and admit I didn't know what I was talking about...:-)[/ref]

    Hey, figuring out you were wrong and getting back to her before she
    wastes *too* much time from your mistake will go a long way towards
    keeping you married!
    --
    David Dyer-Bennet, <net>, <www.dd-b.net/dd-b/>
    RKBA: <noguns-nomoney.com> <www.dd-b.net/carry/>
    Photos: <dd-b.lighthunters.net> Snapshots: <www.dd-b.net/dd-b/SnapshotAlbum/>
    Dragaera mailing lists: <dragaera.info/>
    David Guest

  6. #6

    Default Re: Histogram


    "Burt Johnson" <com> wrote in message
    news:1fy8x6x.ch87ce1ycwadlN%com... 
    > >
    > >
    > > http://www.luminous-landscape.com/tutorials/understanding-series/
    > > understanding-histograms.shtml[/ref]
    >
    > Great article - thanks! Turns out I had misunderstood them when
    > explaining them to my wife when she got her new Canon 10D recently. Now
    > I gotta eat crow and admit I didn't know what I was talking about...:-)
    >
    > --
    > - Burt Johnson
    > MindStorm, Inc.
    > http://www.mindstorm-inc.com/software.html[/ref]

    Just curious, Burt: what explanation DID you give your wife about
    histograms? Don't want you to have to re-visit the scene of the crime, but
    I am intrigued. :-)



    Paul Guest

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