Aperture is one of the three factors that go into creating an exposure (your photograph).
The other two being shutter speed and ISO.
Think of your camera’s aperture as the pupil of an eye. The wider the pupil opens the more light it lets in.
Aperture is measured using the f-stop scale. On your camera you will notice an ‘f’ followed by a number. The number defines how wide the aperture is which affects exposure (how much light you are letting in) and ‘depth of field’ (how much focus/detail you want in your photograph).
The scale is as follows: f/1.4, f/2, f/2.8, f/4, f/5.6, f/8, f/11, f/16, f/22.
The lower the f-stop the more light your camera lets in.
This may seem a bit confusing; surely the higher the f-stop the more light can get in? Well…no.
There’s a reason for this and it’s all down to math’s but i’ll let you watch the videos below as a video is worth a thousand words.
Large aperture = Small f-number = Shallow (small) depth of field
Small aperture = Larger f-number = Deeper (larger) depth of field
In this picture of a Proboscis monkey that I took in Borneo I wanted to focus solely on the monkey’s face so I used a large aperture f2.8
And in this picture I took in El Chalten, South America I wanted to capture detail all the way through the picture and into the distance so I used f22