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Thread: A few bad pixels

  1. #1
    New Member
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    Aug 2013
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    AZ
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    Shaun

    A few bad pixels

    I noticed when doing some time exposures that there are several pixels that are bright blue or red. Looking back at my photos this has been going on for some time. I can only see it if I zoom in on that one location, but of course, I would rather those not be there.

    Are there any tricks for getting rid of these? I'm relatively new to owning a DSLR. I've ruled out the lens by switching it out with another.

    Thanks

  2. #2

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    wm c boyer

    Re: A few bad pixels


  3. #3
    New Member PhoTom's Avatar
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    Tom

    Re: A few bad pixels

    There's a difference between hot and blown(dead) pixels. With long exposures hot pixels are common. Pixels that are blown or stuck are something else. One way to tell is a stuck pixel will be in the exact same spot each time. Hot pixels tend to be random. Either way, you can use the reference from the previous post to deal with them.

    In the case of blown pixels, if it's a new camera, you may wish to return it. If not, there is a service known as pixel mapping which should remove the pixels from your images.

  4. #4

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    Remco

    Re: A few bad pixels

    Hot pixels do tend to stay in place as well, so Shaun could still try to create a black image: do an exposure at the same ISO and time setting as used for the image where you want to remove the hot pixels, but with the lens cap in place. Quite a few RAW converters allow you to subtract this black image from the original. (This is how NR is done in camera for long exposures).

    Also, a stuck pixel will show up in any image, a hot pixel only in a long exposure. Both can show up as a cross-shaped bright spot (several pixels large) in the final image (depending on how the RAW demosaicing is done).

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