Canon® EOS Digital Photography Photo Workshop

10.2. CLEANING YOUR SENSOR

At the heart of your camera is the CMOS sensor, where images that have passed through your lens are converted from analog light to digital information. Arguably the most sensitive and critical component of your camera, if a digital sensor is damaged, your camera's operation and value are seriously compromised.

In front of your CMOS sensor is a thin layer of transparent material called a low-pass filter Technically, this is where dust actually sits when it appears to be on your CMOS, and it is the filter that you clean. Incidentally, this is why dust spots in your images look slightly shadowed — they are not actually directly in contact with the sensor, but sitting very slightly above them. If your camera has the sensor self-cleaning mechanism, it uses what is called a piezoelectric element to literally shake the filter and CMOS using an electrical charge, effectively loosening dust particles so that they fall away.

Because this part of your dSLR gets exposed to dust when you use it normally, such as by changing lenses, this is where dust often accumulates. Additionally, over time, your camera can even generate dust internally as components get older.

Internally, cameras are constructed of exceptionally dust-resistant materials. However, dust still has a way of getting stuck where you don't want it. In many newer cameras, Canon has taken steps to help prevent and deal with dust on your CMOS with a self-cleaning sensor mechanism and an automated dust-delete ...