Pentax K100D Sample Photo (Rerun)

Discussion in 'Digital Photography' started by Bill Tuthill, Feb 13, 2007.

  1. Bill Tuthill

    Bill Tuthill Guest

    In a thread from November 2006, Mike posted this URL,
    which he thought might be an "overexposed K100D shot":

    http://www.pbase.com/image/65541368

    (Definitely not overexposed, but it certainly has problems.)

    After recently reading very positive comments about the K10D,
    and by extention the K100D, I revisited that image.

    Photoshop "Auto Color" certainly works better than "Auto Levels"
    on that image! Afterwards, skin tones look fairly good.

    But what about the weird edge artifacting in the background?
    Is that shadow due to cheap flash attachments (or none at all),
    or is it chromatic aberration from the lens?

    Does anybody have theories as to why skin tones in the Pbase
    posted image are so off-target?

    The previous thread degenerated into nasty comments about the
    model, but I think with aforementioned Photoshop adjustment,
    nobody would have made stupid comments like those.
    Bill Tuthill, Feb 13, 2007
    #1
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  2. Bill Tuthill

    Martin Brown Guest

    On Feb 13, 2:40 am, Bill Tuthill <> wrote:
    > In a thread from November 2006, Mike posted this URL,
    > which he thought might be an "overexposed K100D shot":
    >
    > http://www.pbase.com/image/65541368
    >
    > (Definitely not overexposed, but it certainly has problems.)
    >
    > After recently reading very positive comments about the K10D,
    > and by extention the K100D, I revisited that image.
    >
    > Photoshop "Auto Color" certainly works better than "Auto Levels"
    > on that image! Afterwards, skin tones look fairly good.
    >
    > But what about the weird edge artifacting in the background?
    > Is that shadow due to cheap flash attachments (or none at all),
    > or is it chromatic aberration from the lens?


    It is a common of garden rear silvered mirror slightly out of focus!
    Look at the box in front of the mirror at the left hand side and its
    reflection in the mirror. You are seeing two reflections of the dark
    outline, one from the front glass surface and the dominant one from
    the silvered back mirror surface. Where they overlap incompletely you
    get odd looking artefacts. There are a blonde few hairs out of place
    that allow you to look for chromatic abberration and it is neglible.
    >
    > Does anybody have theories as to why skin tones in the Pbase
    > posted image are so off-target?


    Difficult to know whether or not the model actually looked like that.
    US models and newscasters always look like painted plastic mannikins
    to me. The flash bounce off her forehead and nose certainly isn't
    helping.
    >
    > The previous thread degenerated into nasty comments about the
    > model, but I think with aforementioned Photoshop adjustment,
    > nobody would have made stupid comments like those.


    Oh dear! I may have started this thread down the same track...

    But you cannot blame the camera for distracting objects that the
    photographer leaves behind the model!
    The orchid growing out of her right ear does nothing for me.

    Vicars with trees growing out of them is an old English wedding
    photographer joke.

    Regards,
    Martin Brown
    Martin Brown, Feb 13, 2007
    #2
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  3. Bill Tuthill

    Bill Tuthill Guest

    Martin Brown <|||newspam|||@nezumi.demon.co.uk> wrote:
    >>
    >> http://www.pbase.com/image/65541368

    >
    > It is a common of garden rear silvered mirror slightly out of focus!
    > Look at the box in front of the mirror at the left hand side and its
    > reflection in the mirror. You are seeing two reflections of the dark
    > outline, one from the front glass surface and the dominant one from
    > the silvered back mirror surface. Where they overlap incompletely you
    > get odd looking artefacts. There are a blonde few hairs out of place
    > that allow you to look for chromatic abberration and it is neglible.


    Omigawd! Didn't realize that was a mirror, which explains a lot.
    Makes sense, as I also see a sink. Thanks for your help on this.

    > Difficult to know whether or not the model actually looked like that.
    > US models and newscasters always look like painted plastic mannikins
    > to me. Flash bounce off her forehead and nose certainly isn't helping.


    True, but what's amazing is how much less of a problem it is
    after Photoshop Auto-Color.

    > But you cannot blame the camera for distracting objects that the
    > photographer leaves behind the model!
    > The orchid growing out of her right ear does nothing for me.


    Putting a mirror in the background is fairly dim witted. I'd say
    the orchid(?) is a minor infraction compared to that.

    > Vicars with trees growing out of them is an old English wedding
    > photographer joke.


    In the middle ages, I'm sure that had some iconographic significane.
    Bill Tuthill, Feb 14, 2007
    #3
  4. Bill Tuthill

    Mike Russell Guest

    "Bill Tuthill" <> wrote in message
    news:...
    > In a thread from November 2006, Mike posted this URL,
    > which he thought might be an "overexposed K100D shot":
    >
    > http://www.pbase.com/image/65541368
    >
    > (Definitely not overexposed, but it certainly has problems.)

    ....
    > Does anybody have theories as to why skin tones in the Pbase
    > posted image are so off-target?


    I wouldn't blame the camera. Everything in the image has a red cast,
    probably due to large amounts of light reflecting off the red wall that is
    visible in the mirror. Images like this one, where the darkest and lightest
    objects are neutral, generally respond very well to Auto Levels - in this
    case Auto Color probably works better because of the high contrast in the
    face.

    The image itself shows a lot of creativity, and is quite good for someone
    without the benefits of a studio who is trying new things with light and
    composition.
    --
    Mike Russell
    www.curvemeister.com/forum/
    Mike Russell, Feb 17, 2007
    #4
  5. Bill Tuthill

    Bill Tuthill Guest

    Mike Russell <-move> wrote:
    >>
    >> http://www.pbase.com/image/65541368

    >
    > I wouldn't blame the camera. Everything in the image has a red cast,
    > probably due to large amounts of light reflecting off the red wall that is
    > visible in the mirror.


    Perhaps the K100D wasn't set to auto-white-balance; most cameras aren't
    very good at AWB anyway.

    > Images like this one, where the darkest and lightest objects are neutral,
    > generally respond very well to Auto Levels - in this case Auto Color
    > probably works better because of the high contrast in the face.


    Really, neutral dark/light make AutoLevels work well? I did not know that.

    > The image itself shows a lot of creativity, and is quite good for someone
    > without the benefits of a studio who is trying new things with light and
    > composition.


    It is more flattering to the model than other images in the Nikki folder,
    except one I think. After Auto-Color, I mean. I like 003a.
    Bill Tuthill, Feb 17, 2007
    #5
  6. Bill Tuthill

    Mike Russell Guest

    "Bill Tuthill" <> wrote in message
    news:...

    [re image with red cast]
    > Perhaps the K100D wasn't set to auto-white-balance; most cameras aren't
    > very good at AWB anyway.


    AWB can be treacherous, since it relies on image data and the computer has
    no idea what it is looking at. The methods used for AWB are proprietary,
    but my guess is most of them toggle in a tri-modal distribution between
    daylight, shade, and tungsten. In spite of being confronted with this
    guessing game, no manufacturer (that I know of) makes a camera with a
    built-in incident light meter / colorimeter. It would seem that that would
    be useful, since it would act as a built in and unambiguous gray reference.
    Evidently that does not work, since no one does it. Which should give us
    pause about relying too much on neutral gray cards for color balance!

    > Really, neutral dark/light make AutoLevels work well? I did not know
    > that.


    AutoLevels scales the values of all three channels to span the same range.
    If the brightest and darkest points in the image are neutral, which is true
    for a majority of images, you get a nice color cast removal. So AutoLevels
    works well for the majority of images, and fails for others. AutoColor is
    AutoLevels in color mode, keeping the original tonality.
    --
    Mike Russell
    www.curvemeister.com/forum/
    Mike Russell, Feb 17, 2007
    #6
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