What is image noise aka iso..

Iso basically is how match sensitive to light your sensor is.For example, a photo with 100iso will look darker than a 800iso one(if you keep the other settings the same).

So what's the caught?Why not to use high iso all the time?
As you can see below the higher the iso the more grain(noise) you get.

How to get rid of that noise?

• Full Frame sensors are better at controlling noise and you can get usable images at very high iso values.(What is Full Frame)
• You can find a lot of programs on the internet that can reduce iso noise but don't over do it because it can cause softness on the images
• Don't use high iso.Use lenses with large aperture, get some flashes and try to light up your shot.