Noise Issue- comments welcome

Discussion in 'Photography Forums' started by longleyc, Aug 24, 2005.

  1. longleyc

    longleyc
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    I come across a weird situation regarding noise. A lass in my digital photography class mailed me the shot to analyse it. I never seen a case this bad. I had to reduce the size to 120kb to upload so I think the hot pixels will be evident.

    The attached picture shows some noise that I would expect from a cheap camera, low lit poor focus shot. That noise is evident. What I find strange are the 4 -6 pixels areas that showing up white/blue/red.

    My guess is the ccd is becoming faulty due to either:

    Thermal noise on certain pixels due to the heat within CCD.
    I might get her to shoot a shot covering the lens and examine by dark frame extraction process.

    Electronic Noise. If the CCD is failing then the stray capacitances might be causing these multi pixel noises. That might explain a signal to noise ratio problem.

    My thinking here is that some of the individual ccd sensors are being overcharged and causing multi hot pixels in the image. Exact cause: Unknown.
    Heat? CCD design? poor noise algorythm?

    I dont think its dust on the CCD or lens as there are red and blue pixels too.

    Comments please.
     

    Attached Files:

  2. mr jones

    mr jones
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    what camera? settings etc?

    should she really be posing like that :thumbsdow
     
  3. rhardaker

    rhardaker
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    looks like a camera phone to me!
     
  4. MattB1

    MattB1
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    Looks OK to me :D
     
  5. mattym

    mattym
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    model is fine, as said, its a cameraphone or webcam!!!

    what sort of classes require shots like that?????
     
  6. sorbiegunner

    sorbiegunner
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    I assume you're the teacher of this 'digital photography class'. I'm afraid to say that anyone who mentions 'dark frame extraction process' in any context whatsoever is a wee bit to advanced to benefit from my advice/comments, but for what it's worth I'd plump for a combination of poor lighting and bad equipment as being the main culprit.
    I'd definitely forget all about capacitancies and the like, that seems like a subject more suited to a digital camera fixing class to me.
    As for individual ccd sensors being overcharged, it's difficult for me to tell as I was charged for a bulk lot of millions of the blighters and I've never bothered to work out what the charge for each individual one would be, also you'd have to know what percentage of the overall amount she was charged for the camera was put down to sensors. :D
     
  7. seany

    seany
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    Not sure anybody's checking the noise out:laugh:

    Really does looks like a web cam shot
     
  8. Johndm

    Johndm
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    Wonderful Breasts..... :rotfl:
     
  9. seany

    seany
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    Some serious barrel distortion there:laugh:

    Seriously though, she sent you that :eek:

    I think the biggest noise in that photo is that it's screaming, come get me:laugh:

    She's got to fancy you mate
     
  10. longleyc

    longleyc
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    Heh guys!

    Thats tame! But I wont post the other sexy snaps. Not dirrrty pics (I wish) but sensous. Sadly, she likes me for my brains but not where my brains are kept!

    So my technical post hasnt got too far. :)

    Sitting here thinking made me realise that I think they are hot pixels and they are tending to show on her shots in low light without a flash. I guess the cam ups the ISO in auto mode thus causing the hot pixels on a crap digital camera. Amplification of the signal is what gives you a higher ISO and the charges leak onto adjacent photosensors above the "noise floor". Severe cases causes noise and abberrant hot pixels.

    So if you see this, you know what it is :)
     
  11. mr jones

    mr jones
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    make up girl (no seriously theres a clinique box next to her...)

    as i said, what settings camera etc

    it could just be a crap camera on the highest ISO, we need to know.

    looks buggered, show up unanouncec and show her your extensive zoom capability and let her play with yours.







    i mean camera, you dirty minded individuals
     
  12. longleyc

    longleyc
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    Okay mrjones, she said this ones for you.

    Its a cheapo Kodak camera. Ill suggest using the flash and lower ISO`s.
     

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  13. mr jones

    mr jones
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    check out the size off those oranges!!!!!


    (does she know your posting pics of her on tinternet?)
     
  14. longleyc

    longleyc
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    No!

    End of thread.
     
  15. Johndm

    Johndm
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