Aperture

Aperture is ONE of the three pillars of Photography, the other two being ISO and Shutter Speed.
Aperture is a fancy term for a hole.
Your lens has an aperture - small hole - that let's light into your camera.
The larger the aperture (hole), the more light that’s let in.
The smaller the aperture (hole), the less light that’s let in.
The pupil is essentially what we refer to as Aperture in photography.
Aperture also controls depth of field, which is how much of our image is going to be in focus.

The size of the opening is measured in f-stops. (written as “f/” followed by a number)
Each f/stop lets in twice as much light as the one after it.
Changing the f‐number changes the size of the aperture, changing the amount of light that passes through the lens.
They are a bit confusing because f-stops are inversely related to the size of the aperture:
Large f-stop number = small aperture = less light
Small f-stop number = large aperture = more light

APERTURE with Star Wars LEGO.mp4

DEPTH OF FIELD - A side effect of Aperture

Depth-of-Field is a term that refers to how much or how little of the scene is in sharp focus.
The wider that you open the aperture (smaller f-stop number), the more shallow your depth-of-field. (less in focus)
Shallow or Narrow Depth-of-Field means that only the foreground will be in focus, the background will be blurred. (great for portraits, macros (close-ups) and sports.
The more you close the aperture down (higher f-stop number), the larger your depth-of-field. (more in focus)
Large Depth-of-Field means more of the image will be in focus.

DISTANCE BETWEEN YOUR LENS AND YOUR SUBJECT.

- - The closer your camera lens is to your subject, the more shallow depth of field you will have in your image and the more ‘out of focus’ (or softer) your background will become.
  - Pull your camera far away from your subject and more items will be in focus, even when using the same aperture. See the examples below where both are using the same Aperture setting of f/2.8.