ISO

So I'm working on really learning to use my camera as more then a large point and shoot. One thing I've never understood was ISO. So I read up on how to change it on my camera and I've been playing. Here are a series of shots I took starting with a low ISO and getting larger:

This is what works for me. I can read about it a thousand times but when I see the difference it makes sense to me. So a lower ISO lets in more light, while a higher ISO lets in less light. Now I get it. And I can change the ISO on my camera on the fly now. Baby steps....baby steps......