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Thread: Problem regarding DSLR

  1. #21

    Default Re: Problem regarding DSLR

    Quote Originally Posted by mickie View Post
    Ya, it looks like dead pixel to me as well. I wonder too...
    where can i find this pixel mapping?
    not sure about nikon. for minolta, it maps every first day of the month. maybe you can ask some nikon users about it.

  2. #22
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    Default Re: Problem regarding DSLR

    I think TS is referring to the small bright dots in the middle of the red circles? Dust would show up as dark shadows. If it's not just high ISO noise, then it seems like dead pixels...

  3. #23

    Default Re: Problem regarding DSLR

    Quote Originally Posted by Gengh View Post
    I think TS is referring to the small bright dots in the middle of the red circles? Dust would show up as dark shadows. If it's not just high ISO noise, then it seems like dead pixels...
    IF it's dead pixels, means something wrong with the sensor? Under warranty so it's ok right?
    This is a enlarged picture of it.
    Last edited by mickie; 11th July 2007 at 02:37 AM.

  4. #24
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    Default Re: Problem regarding DSLR

    I have no experience with dead pixels yet, so I can't be sure.... but I think one way to confirm it will be to take several pictures that are completely black (eg. with the lens cap on), in raw with lowest ISO setting and fast shutter speed (to keep noise to minimum), and see if the bright pixels are always there at the same position. A little bit like how you'd test for dead pixels on a LCD screen...

    Can anyone confirm this?? Or is my idea all wrong somewhere?

    Anyway, if they are dead pixels, then probably need to get the sensor changed.... not sure if cameras have similar dead pixel exchange policies like for LCD screens.

  5. #25
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    Default Re: Problem regarding DSLR

    Quote Originally Posted by Gengh View Post
    I have no experience with dead pixels yet, so I can't be sure.... but I think one way to confirm it will be to take several pictures that are completely black (eg. with the lens cap on), in raw with lowest ISO setting and fast shutter speed (to keep noise to minimum), and see if the bright pixels are always there at the same position. A little bit like how you'd test for dead pixels on a LCD screen...

    Can anyone confirm this?? Or is my idea all wrong somewhere?

    Anyway, if they are dead pixels, then probably need to get the sensor changed.... not sure if cameras have similar dead pixel exchange policies like for LCD screens.
    I'm newbie to DSLRs, but from my (limited) working experience with CCD/CMOS sensors, to find out if its 'hot' (dead) pixel, cover the lens cap and fire an extended shot. The longer the exposure, the brighter the spot will be.

    Having a 2nd look and the image, I think ealier bro was right to point out its not dust. Coz if its dust, it should not appear so 'focused'.

    ALL CCD/CMOS arrays will come with certain number of 'hot' pixels (up to 1% is acceptable i think). Hot pixels are pixels that are out of 'normal' electrical response range. These are digitally 'replaced' so its not noticable to us. Which means IF indeed its dead pixel, there is no need to change this sensor, just need to send back for recalibration (LCD is another long story).

    Having said the above, i do wonder why this 'hot' pixel is white. Coz there are no white pixel on a color array. Confusing huh?

    Cheers!

  6. #26

    Default Re: Problem regarding DSLR

    I brought it to NSC and the customer service officer said that it might be dead pixels. So now waiting for the servicing of the camera. Hope it will not take too long... Thanks for all your help guys!

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