ISO Always set your ISO first. ISO controls how sensitive your camera is to light. The lower the number, the less sensitive your camera, and the darker your photo.
The lower the number, the less grain in your photo. Grain increases as the number increases. See the Grain?
Final Thoughts on ISO Don’t use any ISO bigger than you need. If it is a sunny day, ISO 100 or 200 is great. If it’s dark or you’re indoors, you’re going to have to crank that number up, possibly to 800 or 1600.
F-Stop The lower your F-Stop number, the more light will be let into your camera. Think about it like the pupil of your eye. The smaller the number, the wider the hole, and the more light you have.
F-Stop and Depth of Field F-Stop also controls something called Depth of Field. DOF is how far back your photo will be in focus. A wide F-Stop creates a small DOF, and a small F-Stop extends it farther. Shallow DOF F- 1.8 Extended DOF F- 22
Shutter Speed Shutter Speed is measured in fractions of a second. It controls how quickly the shutter in your camera opens and closes. The smaller the fraction, the darker your photo.
Shutter Speed and Motion Blur Shutter Speed is VERY important for things like Sports photography. The lower the fraction, (like 1/25) the more motion blur your photo will have. This isn’t a problem if someone is standing still, but if someone is running for a touchdown, you need a higher fraction, like 1/200. 1/3 1/1001/200