Strange dirt problem

Discussion in 'Digital Photography' started by google.20.jbloggs, May 22, 2005.

  1. I have a D70, about 2 weeks old.

    At very high f-stops, there are 5 or 6 dirt specks on the images, which
    become blurred at lower f-stops. (specks are always in the same place)
    Replacing the lens made no difference, but there is no obvious dirt on
    the sensor, and taking a shot with no lens gives no dirt. Also, if the
    dirt were on the sensor, it would look the same no matter what the
    f-stop, right?

    So it's not the body, and it's not the lens...

    Any ideas???
     
    google.20.jbloggs, May 22, 2005
    #1
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  2. google.20.jbloggs

    John Bean Guest

    Wrong. The dust particles cast a shadow on the sensor
    (they're resting on the filter above the sensor itself). The
    wider the aperture the softer/larger the shadows. The dust
    will not be visible to the unaided eye, follow the
    recommended cleaning procedure. This may help:

    http://www.cleaningdigitalcameras.com/index.html
     
    John Bean, May 22, 2005
    #2
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  3. google.20.jbloggs

    Cynicor Guest

    It happens. The dirt is actually on the sensor - or just above it, on
    the filter. There are several ways to clean it, some scarier than
    others. I have had good success by holding the camera face-down, doing
    the mirror lock-up through the menu, and then giving it a few puffs with
    a Giotto Rocket air bulb. A little puff or two of gentle air will
    usually get the larger dust strands off the sensor.

    You'll see them a lot more clearly at high f-stops than low f-stops
    because the angle of the incoming light is less. It's the same reason
    you can blur distance at low f-stops.

    To make sure you've got it clean, put a lens on, set it to the smallest
    aperture, point it at a white wall, and take a photo (flash will do).
    Then look at the resulting all-white shot.
     
    Cynicor, May 22, 2005
    #3
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