Little Black Dot On Pix

Discussion in 'Digital Photography' started by Logan Spitznauer, Apr 4, 2005.

  1. I have a Sigma SD-9 which has a little black dot in the lower right hand
    side of 99% of my pictures. Sometimes it's sharp, sometimes it's subdued.
    Could I have burned it? Is there a tiny nick or foreign object on the
    lens/mirror/cmos?

    What do you suggest I do to troubleshoot this?
    Logan Spitznauer, Apr 4, 2005
    #1
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  2. Logan Spitznauer <> wrote:
    : I have a Sigma SD-9 which has a little black dot in the lower right hand
    : side of 99% of my pictures. Sometimes it's sharp, sometimes it's subdued.
    : Could I have burned it? Is there a tiny nick or foreign object on the
    : lens/mirror/cmos?

    : What do you suggest I do to troubleshoot this?

    It may be a spot of dust on one of the lens elements in your camera lens.
    Probably on the front element. If this is a zoom lens, changes from wide
    to tele would explain why it is sharp in some images while it is out of
    focus on others.

    I would think that if there was a flaw or speck of dirt anywhere after the
    lens it would remain at the same focus and location all the time. You
    mentioned it's stable in location so it must not be on a rotating/moving
    lens element. But since it goes in and out of focus, it must be on a
    moving element. And it is possible for a spot on the front of a macro
    would be in or near enough to the Depth-of-field envelope to be in focus
    or nearly so. While when the lens is at a long telephoto length, it would
    blur, possibly all the way out to invisibility.

    The solution would depend on where it is. Cleaning the front of the front
    element may get the pesky speck. And if that doesn't work, try doing the
    same to the rear most lens element. But if neither work, you should take
    the camera and lens to a reputable dealer/repairer. Don't try to
    disassemble the lens to "get that pesky dust blot" yourself. It would be
    very likely you would never be able to get it back together again.

    JMHO

    Randy

    ==========
    Randy Berbaum
    Champaign, IL
    Randy Berbaum, Apr 4, 2005
    #2
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  3. Logan Spitznauer

    Charlie Self Guest

    LOgan Spitznauer asks:
    >> have a Sigma SD-9 which has a little black dot in the lower right

    hand
    side of 99% of my pictures. Sometimes it's sharp, sometimes it's
    subdued.
    Could I have burned it? Is there a tiny nick or foreign object on the
    lens/mirror/cmos?


    What do you suggest I do to troubleshoot this? <<

    Shoot a stopped down (f15, f22) shot of the sky or a light colored
    wall. Check and see exactly where the speck is.

    If after cleaning your lens, the speck is still there, it's probably on
    your sensor. Use your manual's instructions for removing the lens,
    raising the mirror, and clean the sensor. There are innumerable posts
    on here about sensor cleaning...I prefer using Sensor Swabs and Eclipse
    cleaner if wet cleaning is needed. Start with a small blower first to
    see if that works. Then go to the heavier duty cleaning. If you mess
    up, you're looking at a pretty good bill to repair the camera, probably
    a bit more than they'd charge to clean the camera (someone once quoted
    $75 or $100 for in-shop sensor cleaning, which is a lot of money to
    spend for something that might need to be done again in a week).
    Charlie Self, Apr 4, 2005
    #3
  4. "Logan Spitznauer" <> wrote in message
    news:8t54e.3284$k57.2869@fed1read07...
    >I have a Sigma SD-9 which has a little black dot in the lower right hand
    >side of 99% of my pictures. Sometimes it's sharp, sometimes it's subdued.
    >Could I have burned it? Is there a tiny nick or foreign object on the
    >lens/mirror/cmos?
    >
    > What do you suggest I do to troubleshoot this?


    If the spot appears in every photo regardless of which lens you are using
    than it is probably dust on your sensor. This is normal for a DSLR and easy
    to clean. The SD9 manual has instructions on how to clean the sensor,
    including removing the dust protector, it's very easy to do. I clean my SD9
    sensor with a 100% nylon foundation makeup brush, it cost only $ 9.99 US
    which is a lot less for the same brushes from VisibleDust. You simply blast
    a bit of air on the brush from a can of compressed air (this gives the nylon
    a static charge) and then wipe it across the sensor. It will pick the dust
    off of the sensor.
    Peter A. Stavrakoglou, Apr 4, 2005
    #4
  5. Thanks. It is a zoom lens. I'll try another lens first, then the cleaning,
    then the sensor.


    "Logan Spitznauer" <> wrote in message
    news:8t54e.3284$k57.2869@fed1read07...
    >I have a Sigma SD-9 which has a little black dot in the lower right hand
    >side of 99% of my pictures. Sometimes it's sharp, sometimes it's subdued.
    >Could I have burned it? Is there a tiny nick or foreign object on the
    >lens/mirror/cmos?
    >
    > What do you suggest I do to troubleshoot this?
    >
    Logan Spitznauer, Apr 4, 2005
    #5
  6. Logan Spitznauer

    Bill Hilton Guest

    > I have a Sigma SD-9 which has a little black dot in the lower right
    > hand side of 99% of my pictures


    Dust on the sensor.

    > Sometimes it's sharp, sometimes it's subdued.


    Because of different apertures. Shoot wide open and you likely won't
    see it, shoot stopped down to f/22, especially with a light subject,
    and you'll see it.

    >What do you suggest I do to troubleshoot this?


    Shoot a white subject at f/22 and look at the file at 100%. Then read
    up on cleaning the sensor.
    Bill Hilton, Apr 4, 2005
    #6
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