Stuck pixels and the 300D, 10D, D60

Discussion in 'Digital Photography' started by BG250, Sep 24, 2003.

  1. BG250

    BG250 Guest

    These are based on the same sensor (I think the D60 does have a minir
    difference). Can anyone with these cameras report on:
    Any problem with stuck pixels?
    Performance with hot pixels in low light situations?
    Thanks, bg
     
    BG250, Sep 24, 2003
    #1
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  2. So far, no problems with my Digital Rebel. Ran the standard test with the
    lens cap on and the result is pure black.
     
    Charles Schuler, Sep 24, 2003
    #2
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  3. BG250

    JPS Guest

    In message <>,
    Do you mean as far as you can see, or upon inspection with the
    histogram? I get a small amount of blue and green signal, uniform
    across the sensor, on my 10D. I believe it is from the LEDs in the
    viewfinder, because the color is just about right.
    --
     
    JPS, Sep 25, 2003
    #3

  4. I have found the best utility for evaluating dead or hot pixels to be Dead
    Pixel Test, which is a free downloadable utility at http://tinyurl.com/m5zf
    .. Shoot the inside of your lens cap (with the viewfinder eyepiece covered)
    in TIF mode at whatever ISO and/or shutter speed you want and you will see
    each pixel in question with the coordinates listed. Works for evaluating
    scanner noise too.

    HMc
     
    Howard McCollister, Sep 26, 2003
    #4
  5. BG250

    Ray Fischer Guest

    The camera turns off those LEDs during exposure.
     
    Ray Fischer, Sep 26, 2003
    #5
  6. BG250

    Nils Rostedt Guest

    Has anybody actually experienced stuck pixels on these cameras, or seen
    reports about any?

    TIA
    Nils
     
    Nils Rostedt, Sep 26, 2003
    #6
  7. Hot or dead ("stuck") pixels are a fact of life with any digital imaging
    technology. This is true of charge-coupled devices (CCD) such as digital
    camera sensors or scanners, or digital display devices such as LCD's, DLP's,
    and plasma displays. Some such pixels are more visible than others, but it
    is a rare digital imaging device that has none if you look close enough.

    HMc
     
    Howard McCollister, Sep 26, 2003
    #7
  8. BG250

    JPS Guest

    In message <bl1q6t$r97$>,
    That's what I assumed before I did the tests, but the data suggests
    otherwise. Perhaps the LEDs have some capacitance in their support
    circuits, and glow for a short period after the power is cut.

    It is clearly not noise; the standard deviation is very low in both the
    green and blue chanels, just like in the red channel. The mean,
    however, is zero for the red channel, and between 1/2 and 1 (out of 255)
    in the blue and green channels.
    --
     
    JPS, Sep 26, 2003
    #8
  9. The histogram shows one vertical line at the far left. The other details
    follow. Hope this helps.

    File Name
    IMG_0091.JPG
    Camera Model Name
    Canon EOS DIGITAL REBEL
    Shooting Date/Time
    9/24/2003 8:25:48 AM
    Shooting Mode
    Manual
    Tv( Shutter Speed )
    1/4
    Av( Aperture Value )
    13
    Metering Mode
    Center-weighted averaging
    ISO Speed
    400
    Lens
    18.0 - 55.0 mm
    Focal Length
    50.0 mm
    Image Size
    3072x2048
    Image Quality
    Fine
    Flash
    Off
    White Balance
    Auto
    AF Mode
    AI Focus AF
    Parameters
    Contrast +1
    Sharpness +1
    Color saturation +1
    Color tone Normal
    Color Space
    sRGB
    File Size
    959KB
    Drive Mode
    Single-frame shooting
    Owner's Name
    Camera Body No.
    0560005734
     
    Charles Schuler, Sep 26, 2003
    #9
  10. BG250

    Alfred Molon Guest

    But most cameras have internal bad pixel maps, which they use to compute
    away the bad pixels. Some cameras (such as the Olympus ones for
    instance) have an inbuilt pixel mapping function, which allows the user
    to automatically update this bad pixel map when a new pixel goes bad
    (happens from time to time). This way you avoid having to send the
    camera to the manufacturer for service.

    Does the 300D have such a pixel mapping function ?
     
    Alfred Molon, Sep 27, 2003
    #10
  11. What about stuck lines? I have found in my camera, and others I have
    tried, that on certain images if you stretch contrast you will see lines
    in smooth areas. I presume these are entire lines on the sensor that
    are bad, that are interpolated by the firmware. I've seen them in both
    my D60 and a 1Ds I borrowed.

    You won't find stuck pixels on a modern high quality camera, they long
    ago started finding them and interpolating them. I suspect these big
    sensors have many stuck pixels, and indeed entire bad lines. Nobody
    else see these?
     
    Brad Templeton, Sep 27, 2003
    #11
  12. My understanding is that a row of bad pixels, as opposed to just one, means
    a major problem with the sensor and something that can't be re-mapped
    effectively, or so I was told by Fuji Service in Edison, New Jersey. They
    told me that that is the only pixel problem for which they would replace the
    sensor under warranty, otherwise they just remap.
    Bad pixels can come and go. Some appear after the sensor is initially
    mapped. I had a hot pixel show up on my Fuji S2 Pro about 2 weeks after I
    got it. It was red, and right in the middle of the frame. I was going to
    send it back for remapping, then it disappeared. About a week later, it
    showed up again. Had the same thing happen on a laptop LCD screen, but I was
    able to massage it away.

    HMc
     
    Howard McCollister, Sep 27, 2003
    #12
  13. BG250

    Andrew Guest

    I had a stuck pixel on a new G3. I exchanged it for another one.

    Andrew
     
    Andrew, Sep 27, 2003
    #13
  14. So do you have none of these lines in your D60 or 1DS or whatever you
    have?
     
    Brad Templeton, Sep 29, 2003
    #14
  15. No, not from stuck pixels. The Fuji S2 Pro does occasionally manifest lines
    of noise in certain overexposed circumstances (
    http://forums.dpreview.com/forums/read.asp?forum=1020&message=6122309 , but
    it's a characteristic of certain exposure circumstances in conjunction the
    pattern of CCD elements in Fuji's sensor. I only read about it on the DP
    forum, haven't actually seen it on my own camera.

    My camera has a couple of hot pixels which show up even at relatively short
    shutter speeds and low ISO, but they are certainly isolated as shown by
    running Dead Pixel Test. That utility would clearly show rows of bad pixels.
    When I get a chance, I'm going to send it back to Fuji to get it remapped.

    If you have pixel lines, run Dead Pixel Test on a TIF.

    HMc
     
    Howard McCollister, Sep 29, 2003
    #15
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