What is Aperture?
Aperture is like the pupil part of the eye. It can be opened up or closed down depending on how much light you want to enter the camera.
When you are in a low-light situation you want the aperture opened up as much as possible. In bright situations you have the option to close the aperture down to let in less light.
An f-stop is the number on your camera that tells how open or close the aperture is.
The most confusing thing about aperture and f-stop is the smaller f-stop number the larger the aperture opening and the more light you are able to let in. The larger the f-stop number the smaller the aperture opening and the less light you are able to let in your camera.
Aperture/F-stop and Depth of Field
Aperture not only lets in light--it also is one way to control depth of field.
Depth of field is quite simply the amount of your images that is in perfect focus between your camera and the farthest your eye can see.
When our eyes survey a scene everything we see is in focus (unless your eyesight is terrible!)
How to Adjust Aperture on Your Camera
Make sure you are in Manual Mode prior to following any of these instructions below!
To set your aperture on the Canon Rebel series cameras, depress the shutter release button until the meter is activated. Then, using your thumb, hold in the Av button on the back of the camera, and then use your index finger to turn the Main dial right for a smaller aperture (large f-stop number) or left for a larger aperture (small f-stop number).
To set your aperture on the Canon EOS series cameras, depress the shutter release button until the meter is activated. Then, using your thumb, turn the large dial on the back of the camera.
To set your aperture on Nikon's entry level cameras, depress the shutter release button until the meter is activated. Then, using your index finger, hold down the button with the little aperture circle next to it on the top of the camera, and then use your thumb to turn the Main dial.
To set your aperture on Nikon's semi-pro or pro line cameras, depress the shutter release button until the meter is activated. Then using your index finger, turn the sub-command dial on the front of the camera beneath the shutter release button.
Example 1: Lets say I want to take a portrait of my daughter and I want her to be in focus and the background to be blurred. I would choose an open aperture (like f/2.8) and focus on her eye. She would be in focus but the background and any elements in front of her would be blurred.
Example 2: I want to take a shop of the beautiful landscape around my house. Because I want everything between me and the mountains to be in focus I would choose a closed down aperture of f/16 or f/22 to ensure that all the landscape details are in focus.
One Final Note
You may find that you don’t have access to all the f-stops mentioned above. Your lens controls the lowest aperture you can access. Your camera controls the highest aperture you have available.
Don't Miss the Next Posts in This Series!
I hope this series has helped you Master Shooting in Manual Mode. If you’ve missed any of the posts in the series, you can go back and read/review them at any time by following these links!