When you take a photo, the amount of light that reaches the sensor is known as the exposure. It is basically controlled by two settings: Shutter speed and aperture.*
Shutter speed is simply the time the shutter is open, typically measured in fractions of a second such as 1/125 s, 1/250 s or 1/500 s. The longer it takes, the more light you get.
But what is aperture, and what exactly do these numbers such as 1.4, 2 and 2.8 mean?
*OK, there is also ISO, but that’s something slightly different.