ISO is something that has a very long name that I don't really know what it is at the moment if you want to look it up be my guest. But getting back to the subject, ISO is a feature on the camera that sucks in light. Usually people have it on AUTO because no one knows what it is. And that's fine if you are just taking picture of your friends and people that you hang out with. But with Photography, when you want thing to look more artistic then you want to mess with the ISO. Look at the picture above see how they change and the ISO goes up I uploaded photo's with; flash AUTO ISO, 50 ISO, 400 ISO, and 5000 ISO. Can you see the differences in the flash and the ISO ones? Flash just makes everything look flat and really fake and oily. No one wants to look like that in an artistic photo, but I'm getting side tracked. When you want to capture beautiful light that happens to be in your background you don't want to lose it with flash. Flash makes the light look like they’re not even on, they vanish as soon as that flash goes off and it just looks stupid. The only thing that you have to be careful with is when you are out side and it is flipping bright out there. And you have the ISO pumped all the way up to 5000 or up. Trust me all of your picture will come out white. Yah, I have got this post so mixed up I got myself confused. But I think that what you need to know about ISO if there is any question or confusions which I would doubt please fill free to contact me as soon as possible. Thank you again my reader, good bye.