Originally posted by stgmgr I have a K100D Super(6.1 MP)
Recently I did some low light shooting and had to use ISO 1600 or 3200.
The noise was very noticeable.
Would it have been less noticeable if I had more Megapix?
Basically there are 2 main sources of noise in electronics: free electrons (caused by temperature) and cross talk.
The first is noticeable as random (white) noise, the latter often as banding.
There are some ground rules here; if you amplify an analogue signal, you also amplify the containing noise.
Increasing your ISO is like turning up the volume of your amplifier.
Try that once without any signal, you'll hear some noise coming from the speakers. That's why we call the spickels in your picture "noise" although you can see it, not hear it...
Hence, in low light, you increase your camera's ISO setting = increasing signal amplification -> you are also increasing noise.
If you compare two sensors build using the same semi conductor processing, the one with the less pixels is the one with the (presumably) largest pixels.
The larger a pixel, the more surface to there is to capture incoming photons. The more photons captured, the more signal, the less amplification (ISO) needed, the less noise.
A common approach with vendors is noise reduction.
That is in camera software detecting noise patterns and blending / smearing them with the surrounding pixels. So you get less noise, at the cost of losing resolution caused by the smearing.
Newer CMOS sensors generate less noise making more pixels per sqaure inch possible without too much noise. However, with the same technology used to make a 6Mp sensor, it will always generate less noise than a 10Mp sensor with that technology.
Your K100 has a somewhat older generation CCD sensor, a more modern CMOS senor can hold more pixels and still generate less noise.
Have fun.
- Bert