Noise?

[photogincollege]

Could someone please explain what noise is?.

 

[Big Mike]

Digital Noise is when pixels aren't the color they are supposed to be. It's caused by interference of the digital signal, somewhere between the light hitting the sensor and the image being saved. It can also be brought out by processing of the image.

Cameras with smaller sensors (especially high mega pixels on small sensors) are more prone to producing noise. That is why DSLR cameras, with larger sensors, are so much better.

When you turn up the ISO setting on a digital camera, the signal is amplified, which increases the interference and the noise in the image.

It's actually a little like film grain, if that helps.

See this link