Using ISO pt. 1
The ISO speed settings on your camera control how sensitive your camera’s sensor is to light. It's the third ball you have to juggle when you control your exposure. But how do you use ISO Speed in the real world?
If you need to speed up your shutter there are two ways to do it. You could open the aperture wider to let in more light, but you might not want to do that because it'll reduce your depth of field.
The other would be to make your camera more sensitive to the available light by increasing your ISO. If the camera's more sensitive then you can use a faster shutter speed without changing the aperture and still get the correct exposure. Cool hey!
There is a downside though. As you increase the ISO the image starts to lose quality the higher you go. How much depends on individual cameras. Generally the newer and more expensive the camera is the better quality it'll achieve at high ISO. High megapixel cameras perform better at higher ISO because there are more pixels per cm to record data which means less grain and noise in the image.
If you’re not sure what ISO is, have a look at the ISO Speed film first then come back to see how to use them.
The technical part of 7 Blocks of Photography is great and needed, but you are the inspiration to keep coming back.