Aperture is a hole in the lens that consists of a small set of blades that control how much light enters into the camera. We can widen the set of blades to let more light into the camera or close down the blades to allow less light into the camera. There are two things that I want you to understand about aperture:
1) F stops
2) Depth of Field (DoF)
In essence, a higher f-stop (such as f-22) means a smaller hole or a “closed down” of the blades in the lens that allow less light into the camera. A lower f-stop (f2.8) means a larger hole or a “wide open” blade in the lens that allow more light into the camera.
Suppose you are in a low light situation and you want to take a picture. What kind of aperture do you want to use? BINGO! A lower f-stop such as f-2.8 or even f-1.2 for some really expensive camera lens.
The other part that I want you to understand is Aperture controls the depth of field (DoF) of your photograph. Keep in mind that aperture and DoF are closely related because while aperture set how much light goes into the camera it also determines the sharpness of the background. A higher f-stop (f-2.8) means you will get a shallower DoF which means the picture will have a blurrier background. On the other side, if you want more focus in the overall picture you want a deeper DoF which means a lower f-stop (f-22).
Supposedly you are taking a landscape picture at the lake with mountains behind it. Which aperture would you use to keep both lake and mountain in focus? Yep! A higher f-stop like f-22 for deeper DoF.
Doing alright so far? If you understand these two basic relationships about Aperture and DoF then please head onto the next step 4. If you have any questions feel free to contact me for any questions and I’m happy to answer.