Pixel Mapping?

I've had an Olympus PEN E-PL1 for a number of years now and enjoy using it a lot. Never a hiccup or problem and just a fantastic sensor. Anyway, I took some shots for the SOTD thread and as I was looking at the exposures in Photo Shop I saw some hideous pixel ghosts - three of them scattered in various locations. I froze and immediately thought my little friend was slowly dying, or something. A quick web search pointed me to the "Pixel Mapping" function on my camera and now all is well.

So, can someone here tell me what pixel mapping does? If I have to use the function does that mean there's a problem with my sensor or another part of my camera? The camera also made some weird sounds as Pixel Mapping was running and I was wondering what that was, too.

Thanks.

CaptainGreybeard said:

http://lmgtfy.com/?q=olympus+pixel+mapping

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Nicely played, and thank you.

Pixel mapping eliminates dead pixels by interpolating the pixel data from neighboring pixels.

If your sensor has dead pixels, they appear as blank pixels in each image win the same spots. After running the pixel mapping feature, those blank areas are filled in with guessed data. It's great that Olympus cameras have the pixels mapping feature inbuilt.

Do not confuse dead pixels with hot pixels. A hot pixel will also show up as a bright pixel. This occurs especially when shooting in low-light conditions and with long exposures. In order to reduce the appearance of hot pixels under these conditions, use what is generally called Dark Frame Subtraction. Olympus calls this confusingly Noise Reduction (not to be confused with Noise Filtering, which is something else entirely). With Dark Frame Subtraction activated, the camera will automatically take a second exposure with the shutter closed and compare the hot spots of this image with the first image. Then the hot spots present in both frames will be eliminated from the image. The disadvantage of Dark Frame Subtraction is that taking an image takes twice as long as usually. So a 30 second exposure ends up taking one minute until you can shoot the next picture.

Interesting, had never heard of pixel mapping before.

Another reason why this place is the best, learnt something new yet again!

It seems to have worked great. I ran it once and took some new shots and all is well! After reading the above article that was linked in the 2nd post, Olympus actually suggests doing it once a year. As I've had the camera for over 4 years, I guess it was time.

Do other camera manufacturers offer pixel mapping as well?

mr_eleven said:

Do other camera manufacturers offer pixel mapping as well?

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All the main camera manufacturers offer in-camera pixel mapping in at least some of their cameras.