whats an acceptable number of hot pixels?

Discussion in 'Digital Photography' started by ian, Nov 23, 2003.

  1. ian

    ian Guest

    Are digital camera's like lcd monitors - ie are a certain number of hot
    pixels considered normal/acceptable?

    I think I may have one on my camera - 1 second of work with pse 2 sorts it
    out but I'mjust interested about what acceptable or not.

    Thanks

    Ian
     
    ian, Nov 23, 2003
    #1
    1. Advertisements

  2. ian

    Doc Guest


    My standard is zero- though I'm willing to negotiate with the
    manufacturer/vendor. My opening offer is $175 off the price per bad pixel.

    Amazing how they find you a perfect one after that;-)

    Doc
     
    Doc, Nov 23, 2003
    #2
    1. Advertisements

  3. Hot pixels are a fact of life with all digital imaging. Unlike LCD screens,
    hot pixels on a digital camera sensor will often be addressed by the
    manufacturer under warranty even if there are only one or two. They do this
    by finding the exact location of the hot/stuck pixel and programming it to
    display an average of the immediate surrounding pixels.

    HMc
     
    Howard McCollister, Nov 23, 2003
    #3
  4. ian

    Jim Townsend Guest

    There should be no bad pixels initially.

    Unlike monitors, bad pixels on a digicam sensor can be mapped out.

    The camera firmware an be programmed to ignore x and y coordinates on the
    sensor and use adjacent pixels to make an approximate of the missing pixel.

    Since the CCD/CMOS construction process isn't perfect, there usually are a few
    bad pixels that show up. These are mapped out as part of the camera
    construction.

    If you have any bad pixels on a new camera, then they missed them in the
    factory. I'd send it back.

    (You can have this mapping service done at any time on most cameras, but once
    you're off warranty, you pay for it).
     
    Jim Townsend, Nov 23, 2003
    #4
  5. ian

    PETERWOJ Guest

    Are digital camera's like lcd monitors - ie are a certain number of hot
    First of all hot pixels depend on the temperature and time of exposure. Keep
    the temperature high enough (hot, humid summer day afer camera was left on
    dashboard of your car for few hours) and keep the shuter open for long time and
    black frame will show thousands of hot pixels. Do the same test in winter when
    camera is cold and you might see none. Since I don't do too many night shots I
    expect no hot pixels visible with shutter shorter than 1 sec. in normal (around
    75F) temperatures. Some cameras (Olympus for one) have build in user function
    where hot pixels can be remaped. Others need to be send to shop and it will
    cost to do it after warranty expires. So you should do it now when it's free.
    Hot pixels almost never fix themselves and usually get worse with time. If you
    into astrophotography your criteria could be different.
     
    PETERWOJ, Nov 24, 2003
    #5
  6. ian

    Ron Hunter Guest

    For me, 0. Others might be more forgiving.
     
    Ron Hunter, Nov 24, 2003
    #6
  7. Or more practical.

    HMc
     
    Howard McCollister, Nov 24, 2003
    #7
  8. ian

    Azzz1588 Guest


    However in winter, with the back panel LCD on, after a while the
    heat buildup causes hot pixels during long exposures
    (16 sec on my C 4040Z)
























    "Only a Gentleman can insult me, and a true Gentleman never will..."
     
    Azzz1588, Nov 24, 2003
    #8
  9. ian

    gr Guest

    Zero is my standard as well, and very practical if I stick to Olympus
    cameras. They have a menu item called "pixel mapping", which removes all hot
    and dead pixels from the sensor map. So, even years from now, my camera will
    be free of annoying hot or stuck pixels. This was a critical feature for me
    when buying my latest camera, as my previous digital camera all developed
    hot pixels visible even in daytime shots. Once you know the hot pixels are
    there, you can see them in every image and they become very distracting.
    There are ways to remove them in software, but it's time consuming and
    degrades the image.

    This newsgroup tends to be very bias towards Canon, which probably explains
    why nobody has mentioned pixel mapping. Canon can do pixel mapping, but you
    have to ship the camera back to the manufacturer and get them to do it for
    $$$.
     
    gr, Nov 26, 2003
    #9
  10. ian

    Azzz1588 Guest



    Yes, I have to admit, it is a NICE feature !!

    It took over a year for my C 4040Z to develop a stuck pixel, and
    I just mapped it out thanx to pixel mapping :)




















































    "Only a Gentleman can insult me, and a true Gentleman never will..."
     
    Azzz1588, Nov 27, 2003
    #10
    1. Advertisements

Ask a Question

Want to reply to this thread or ask your own question?

You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.