Hot Pixels

Discussion in 'Digital Discussion & Q&A' started by teishu, Mar 13, 2007.

  1. teishu

    teishu TPF Noob!

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    Hi, whenever i tak pictures in lowlight i get awful hotpixels covering my picture, why is this ? How can i prevent it. here is an example:

    [​IMG]

    [​IMG]

    Thanks
     
  2. Big Mike

    Big Mike I am Big, I am Mike Staff Member Supporting Member

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    I'm not certain...but I believe that longer exposures will bring out 'hot pixels' because of a build up of heat on the sensor...or something like that.
     
  3. teishu

    teishu TPF Noob!

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    How do photographers get long exposure pics without them ?
     
  4. Big Mike

    Big Mike I am Big, I am Mike Staff Member Supporting Member

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    I'm not sure...like I said, I'm not even sure that is the actual problem.

    Noise reduction would probably get rid of the hot pixels...or, it would only take a minute in Photoshop to get rid of them.
     
  5. teishu

    teishu TPF Noob!

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    well ive spent 20 mins in PS and managed to get rid of most of the visible hotpixels in one of the photos along with a few other alterations. here it is:

    http://www.juphotography.co.uk/juphoto/main.php?g2_itemId=113

    thanks
     
  6. drgibson

    drgibson TPF Noob!

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    If they are always in the same place or if they are on all images then the ccd ic bad. To test this take a normal exposure of a black surface to see if they still show up, if not then it is just digital noice and you will have to deal with them. To me it looks like the ccd is bad and not noise.
     
  7. astrostu

    astrostu Guest

    Consumer CCDs almost always have hot pixels. Take a picture for 30 seconds or longer with the lens cap on and you'll see 'em.

    For astrophotography, I dark-subtract them out. For practical photography, I usually crop them out, use PS's Dust & Scratches filter, or clone them out. If high-resolution is needed and I don't want to have blurring artifacts from the D&S filter, I would clone them out, or even in the shot of the moon you have, I would just select the moon, invert the selection, and then fill with black.
     
  8. xfloggingkylex

    xfloggingkylex TPF Noob!

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    I have a feeling it is a type of noise, or your P&S's sensor is just prone to producing hot pixels.

    Hot pixels aren't what they sound like, they are actually a pixel that is stuck displaying one color, hence being known as a stuck pixel.
     

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