eos 10d and pixel mapping. has anybody had it done?

Discussion in 'Digital Cameras' started by Mark N, Oct 3, 2003.

  1. Mark N

    Mark N Guest

    I get loads of hot pixels with my 10d when i take exposures of longer than
    10 minutes or so.

    Is it possible to send the camera off and have them mapped out?

    Has anybody had this done to their camera and is it effective in reducing
    the number of hot pixels in long exposures?

    Does it degrade image quality in any way for 'typical' daylight exposure
    times?


    Thanks troops, Mark

    www.derbyshire-butterflies.co.uk
     
    Mark N, Oct 3, 2003
    #1
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  2. Mark N

    Marli Guest

    I would like to see your 10 minute exposure.

    Does the 10D take a dark frame and subtract the hot pixels?
     
    Marli, Oct 3, 2003
    #2
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  3. Mark N

    Mark N Guest

    here is a typical example of a 10 minute exposure

    http://homepage.ntlworld.com/robert.nowak/images/137_3747.jpg

    its about 500Kb and is a 60% jpeg of a raw file. I have done as little post
    processing as possible, and used breezebrowser to convert the file.

    The highlights are fine, but when yo ulook at the darker sections -
    especially the grass at the bottom and some of the windows it looks
    speckled. There about 4 or 5 'really' hot pixels which look like small
    'light bulbs' (theres a biggie in the bottom left hand corner.

    I dont think the 10D does dark frame subtraction separately. I think it does
    it on the fly somehow

    Regards, Mark
     
    Mark N, Oct 3, 2003
    #3
  4. Mark N

    Don Coon Guest

    What ISO was used?

     
    Don Coon, Oct 3, 2003
    #4
  5. Mark N

    Mark N Guest

    iso 100

    the exif data is in the image


     
    Mark N, Oct 3, 2003
    #5
  6. Mark N

    AK Guest

    I don't have a 10D (yet!) but on my Nikon 995, in auto mode even if the ISO
    was set at 100 in Manual mode, it seems to increase the sensitivity (and, I
    think, sharpening) to the max to get a "better" shot and this also tends to
    make long exposure pictures a bit grainy, though I've never seen as many
    artifacts as in the shot you posted. Are you shooting with the ISO set
    manually at 100, or could the camera be trying to reduce exposure time by
    ratcheting up the sensitivity (ISO)?
     
    AK, Oct 3, 2003
    #6
  7. Mark N

    Mark N Guest

    Cheers Jim. Good answer. I think there about 4 or 5 significant hot pixels.
    I how have an explanation for all the little fuzzy dots that dont look as
    big or pronounced as the hot pixels.

    Thats an awesome picture by the way :)

    my intension for the future is to do some star trail photography. I shall
    have a look at photoshop and see if i can make it do something like what you
    described for Gimp

    Cheers, Mark
     
    Mark N, Oct 3, 2003
    #7
  8. Mark N

    JPS Guest

    In message <3f7d5998$>,
    No, it does not. It is ready to take the next picture as soon as a long
    exposure is finished.
    --
     
    JPS, Oct 3, 2003
    #8
  9. Mark N

    PTRAVEL Guest

    I'm curious.

    I've read about the hot-pixel-on-extended-exposure problem with the 10D
    before; it was mentioned in the dpreview.com review of the camera. Is it
    always the same pixels that are hot, or is this the result of some kind of
    random firing during long exposures? If so, I'd think it'd be a relatively
    easy process to take a black frame and then use it as a mask for any long
    exposure shot.
     
    PTRAVEL, Oct 3, 2003
    #9
  10. Mark N

    Guest Guest

    what is frame mapping?


     
    Guest, Oct 5, 2003
    #10
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