Intrigued by this topic, I've decided to go on an Internet Hunt to see what information I could find on it.
One of my first bits of information was found on another forum dating from 2002 (so its a little old)
http://www.pcreview.co.uk/forums/thread-1561266.php
The first thread seems to be a quote from Nikon Singapore, the information is quite interesting, it mentions the red, blue and green pixels and describes taking a shot of the lens cap as I did above. It calls them 'christmas tree artifacting'.
This is what it says (if that forum is ever unavailable)....
A common complaint amongst digital camera owners of all brands, particularly as their cameras get older, is that of pixels that are always on or off ('stuck' or 'dead').What is STUCK Pixel?
A Stuck Pixel is a pixel that always reads high or is always on to maximum power on all exposures. This produces a bright pixel usually of red, blue or green in color in the final image. A Stuck pixel will occurs regardless of shutter speed, aperture size or any other user settings. It will occurs on normal exposure and tends to be more obvious under dim condition as it tend to stand out. What is DEAD Pixel?
A Stuck Pixel (think this was a typo and should have read A Dead Pixel) is a pixel that reads zero or is always off on all exposures. This state produces a black pixel in the final image. Similar to STUCK Pixel, a dead pixel will occurs regardless of shutter speed, aperture size or any other user settings. It will occurs on normal exposure and tends to be more obvious under bright condition as it tend to stand out.
NOTE : Do note that STUCK or DEAD Pixel will occurs at the same location for all images. If the location of the STUCK or DEAD Pixel occurs at different location, it may be a HOT Pixel.
What is HOT Pixel?
A 'hot' pixel is a pixel that reads high(Light Up) on longer exposures, and can produce white, red (orange) or green (yellow green) pixels in longer exposures. The longer the exposure the more visible the hot pixels. These pixels become more evident with longer exposures. HOT Pixel may also occurs when the camera heated up during prolong usage for certain cameras. This is due to the fact that when the CCD get heated up, more electrons wander off into the substract by themselves and result in false positives. It is not possible to have a image that is entirely clean of HOT Pixels during long exposure. Therefore in most of Nikon Digital Cameras there is a Noise Reduction mode that can be set from the menu or from certain scenes mode to reduce the effect of HOT Pixels.
Testing for STUCK and DEAD Pixels
A common mistake in testing for Dead or Stuck pixels is to cover the lens with the lens cap, set the camera to AUTO. Setting to Auto will cause the camera to lower the shutter speed thus result in taking a long exposure. This produces some red, greenish and sometimes white pixels. This is a normal state and it is referred to as Christmas Tree artifacting. In addition, a dead pixel is dead all the time and would not show up with this test since the pixel is black.
STEP 1 : Take some shots of of normal indoor environment such as a portrait.
STEP 2 : Compare two shot using a photo editor such as Photoshop or Nikon Editor where it allows you to compare two images side by side. If you notice there is a bright pixel occurring on one image, do the comparison on the other image, both should have the bright pixel on the same location. if it is on the same location it can be consider as a HOT pixel.
How do I rectify the problem?
You can bring your camera together with your warranty card to Nikon Service Centre where our technician will be able to rectify the problem.
