Camera College
Photographer and writer Marcus is a former editor of Digital Camera
What is aperture all about?
Controlling the size of the hole in your lens might be crucial to making a good exposure, but it also allows you to get creative with sharpness and blur
Changing the aperture of your lens is one of the fundamentals of photography. It allows you to alter both the exposure of a picture and how much of it appears sharply focused. But aperture can be a confusing control to get to grips with, thanks largely to its strange f/number scale, which is seemingly arranged in the wrong order.
The aperture itself requires little explanation: it’s simply a physical hole in the lens that light passes through to reach your camera’s imaging sensor. In most lenses, this hole is formed by overlapping blades that create a diaphragm, which regulates how much light is let into the camera.
Large apertures let more light into the camera; small apertures reduce the amount of light. That bit’s easy enough to understand. What’s more confusing is the set of numbers that represent the size of the aperture. Why does it jump from f/4 to f/5.6 to f/8 and so on? And why does a low f-number such as f/2.8 represent a large
