What does the term "noise" refer to in cameras?

Question

i'm looking for a new camera and in a lot of reviews it refers to the amount of "noise" at different ISO levels. what does this mean? actual sound? or is it some sort of visual thing?

Answer 1

It is a visual thing, noise is referenced as a distortion on the image so to speak.

Answer 2

visual...refers to how smooth or rough the image is when zoomed to 100%....a higher ISO means the image will be rougher and it would be good to use a noise reducing software.  anything over 200 ISO, you will start to see noise.

Answer 3

visual. Noise is no different than you see dirt flower around the object that you are capture

Answer 4

Noise is similar to grain found in film that is high ISO.

In order to make the sensor sensitive in low light situations, the light falling on the sensor has to be amplified ... amplification causes noise (blotchy sections of the image file).  There is another piece to noise as well.  The smaller the pixel, the more noise you can expect at any ISO.  This is why the size of the sensor is so important.  

Since P&S cameras have tiny sensors, they are more prone to noise.  DSLR sensors are over 15 times larger than most P&S camera sensors, so you can see why size is everything when it comes to digital sensors.

Answer 5

is how much sound is created by your camera dont belive the other answers