Today I'm going to talk about hot/dead pixels, those annoying pixels that show up typically on long exposures (starting from around 1 second), one the unwanted effect under the "noise" chapter of digital photography.

First, some interesting information about the topic, then a very interesting trick to remove many hot pixels in Canon CMOS cameras (DSLRs have CMOS sensors)....

Let's start with the theory.

The hot/dead pixel test is done shooting at a completely dark scene, typically with the lens cap on and disabling any noise reduction (unless you want to hide the problem ).