Hot Pixel and Pixel Mapping in Digital Camera

Today, I received an email from My-Olympus mailing list, regarding a member with hot pixel problem in her Olympus E-500. Suddenly this topic began to interest me, since I also owned E-500 second hand.

Basicly, what is Hot Pixel really?

Wikipedia give me this :

Hot pixels are sensors on the CCD with higher than normal charge leakage. On long exposure, they can appear as bright pixels.

Sensors on the CCD that always appears as brighter pixels are called stuck pixels while sensors that only brighten up after long exposure are called hot pixels.

A very good source about hot pixel & how to see/reproduce them can be located here :

  1. The longer the exposure and the higher the ISO and the hotter the temperature of the camera the more hot pixels you will see.
  2. Every camera will have hot pixels showing if you test it with long enough exposures.
  3. All cameras will develop more hot pixels over time.As your camera ages you will have more and brighter hot pixels.
  4. Some manufacturers have dealt with the problem in their newer cameras by allowing user mapout of the hot pixels.Since every camera will likely develop hot pixels if you keep it long enough, you might want to consider this when buying your next camera.

Points taken.

Example of Hot Pixel :

From Olympus website:

In short, even a brand new digital camera will definitely suffers hot pixels, and they will develop hot pixel along the lifetime of the camera.

What Olympus has to say about this issue? (well, I owned Olympus, that’s the first thing I want to hear):

The more pixels your camera’s imaging sensor (CCD) is made of, the more likely some of them may fail. Think of the lights on a Christmas tree.When the string is smaller, the lights usually fire without incident. But the longer the set of lights, the higher the probability one or more individual lights will need repair. These “stuck,” “dead,” or “hot” pixels, as they are often called, can cause the quality of your images to be compromised. Nearly every digital camera, regardless of the manufacturer, includes a sensor that experiences this to some degree. The issue may not be severe enough to be noticed, but if you do notice this phenomenon to occur, look into Pixel Mapping.

Wait, what’s that? Pixel Mapping, sounds familiar, Aha, I’ve seen it on my E-500 menu, but I never used it, ’cause I don’t know what it is for (silly me).
Let’s carry on:

Some digital cameras come with an Automatic Pixel Mapping function right inside the camera that helps prevent faulty pixels from affecting image quality. The feature can be manually selected from the camera’s menu and takes approx. 10-30 seconds to complete, depending on the camera model. By doing so, the location of the faulty pixels will be determined and stored to memory so the camera will automatically compensate for the missing information or incorrect data in subsequent exposures. It is recommended that this function be used at least once a year and if so, your camera should enjoy a much longer period of

Check your digital camera’s instruction manual to see if the Pixel Mapping feature is included.

Oke, I’m on it. Luckily, My E-500 has this feature. But my old Kodax DX-6340 and Sony HCR-90 don’t seem to own this. Sigh, It’s okay, I’m cool 🙂