Over the next few posts on The Craft Blog we will be looking at the three exposure variables (ISO, Shutter Speed, Aperture). 

As we move forward with these tutorials we will break things down and work through shooting in different environment's / situations to help drill all this technical info in.  

To begin with we will be looking at ISO. 

What is ISO?  - ISO is basically the sensitivity of your cameras sensor to ANY light source in the scene but if you want to get real technical is is digital gain/amplification control.  

As we change the ISO value we affect the exposure of ANY light source within a scene.  Let's break it down some more.