Stefanus Prayitno Photography

Noise... ahhh... The one thing that creates a lot of tension :)

Noise in film days is so much different than noise in current digital days. As we all know that noise happens mostly in higher ISO settings. Sometimes it also occures in shadow areas, or single tone areas as well. Higher ISO setting in film era means more light sensitivity. But in Digital age, it means more voltage amplification. What does it mean?

Before, when using film, when you use higher ISO, you will get grain, or noise. That is because you use photo 'sensor' that is more light sensitive. Means that the film gets exposed easier to light. ISO 200 is twice more light sensitive to ISO 100. But when you use higher ISO digital sensor, you amplify your voltage reading.

Digital sensors produce voltage that is according to the light that hits on the sensor. Of course you realize there are 3 different sensors in your digicam. One for Red, one for blue, and one for green. The combination of the three colours will make up the colour that you see on screen. The more light hitting the sensor, the more voltage that is produced (or the other way around, depending on how they design it). If you need more light sensitivity, higher ISO in digital cameras will multiply this reading with your set amount (2x, 4x, 8x, etc) and give you your 'brighter' looks. However, as we all know that in electrical engineering courses they teach you that if you magnify your voltages, you also magnify your noise.

Now it depends on your signal to noise ratio. If you got a big signal and small noise, you may be ok (more megapixel cameras tend to have more signal due to increasing number of pixels in place, thus less noise. Full frame cameras tend to keep more detail in the shadow areas).

Where does noise come from? It comes from all sorts of areas. Conducted, radiated, etc. Too long exposure causes noise, heat causes noise. To illustrate noise, imagine your speaker outputting that unthinkable noise when you don't plug in its input speaker plug.

Film and digital sensor behave differently too when handling shadow-to-highlight areas. Film behaves more like a s-curve shape. Thus amplifies highlight information more and supresses shadow area more. Thus less noise in the shadow area. But digital sensors behaves like linear curve.

CCD sensors react differently to noise too to CMOS sensors. CCD sensors uses a single voltage magnifier for all its pixels, thus creating less noise. CMOS on the other hand magnifies each pixel differently. Thus creating more complexity, and more areas that noise can get into (note, anything conducting no matter how long or short can pick up noise).

Hahahaha... all these ramblings about noise. What is the conclusion?

1. Noise is not all that bad. Some people even like noise
2. Dont avoid CMOS just because it has more noise. See how N**** follows on C**** footsteps and use CMOS now? :)
3. There are softwares thathelps remove noise such as noise ninja, noiseware, neat image noise removal.