Hot pixels, stuck pixels, Minolta/Sony solution

Sometimes, on a digital camera, there are small defect on the sensor. They translate into a pixel or two which seem to be either black, colored (hot) or white (stuck). This is ususally not much of a problem, but it can be very annoying.

On my reliable but old and still alive-and-kicking Konica-Minolta Dynax 7D camera, I noticed on some of the 2500 photos I shot in Brazil last month that there were a couple of white pixels in the upper third of the image. This was not too annoying since white on the sky is usually barely visible and easy to correct by most of the smoothing algorithms. And they disappeared any time I cropped down the image for web usage. However, it was clearly visible on some of the best images that I wanted to keep in high-resolution.

Easy to correct did not mean that I wanted to keep that. So, I started to look for software solutions to correct the problem, but it appears that Minolta, Konica-Minolta and probably Sony digital cameras all share the same approach to hot pixels and stuck pixels. Apparently, once a month, when switching off, the camera will shot a black image and look for stuck pixels to update the dead pixel map of the camera. The swithcing off is longer when this happens (the red light will blink a little longer), but after this step the problem is automatically corrected.

It seems that if you want to correct it by yourself, the only thing that you have to do is to change the date in the camera menu, move it forward at least further than the next 1st day of the next month, switch off the camera (let it do its little game of red light), switch it on again, shoot one picture, go to the menu and change the date back, then switch off the camera.

After this, your Minolta/Sony camera updated its hot pixel mapping and knows where to expect them. It will magically remove them from the picture and just interpolate values from the neighbouring pixels. Instead of having an ugly white spot, you’ll get a microscopic and invisible loss of resolution (one-pixel resolution loss out of 6 to 12 millions, it should be acceptable, eh).

Pretty neat. It works with all cameras of this brand(s). No need for image software on your Mac or PC.