All about aperture
Claire Gillo
Claire Gillo is a photographer and writer living in Devon. She writes articles for a number of photography publications including Amateur Photographer and Digital Camera. Find out more at www.clairegillo.com or follow her on Instagram @clairegillophotography.
1 The basics
Aperture derives from the Latin word apertura, and is defined as a hole or a gap. It controls how much light you let through your lens to the camera's sensor. The amount of light that enters is measured through a system called f stops. By increasing or decreasing the size of the aperture diaphragm it will affect the depth of field in your image. The depth of field is how much of the image is sharp in front of and behind the selected focus point. Other factors contribute to the depth of field too, such as the focal length of the lens, and the camera-to-subject distance; we'll get to that later.
2 Why the f do we use f-stops?
When you start learning about the exposure triangle it's easy to get your head around shutter speed and ISO as they follow a basic numbering system. The aperture f-stop system seems like a random arrangement of numbers, but hang on there is logic. The f-number is the ratio of the lens's focal length (f stands for focal length) to the diameter of the aperture hole. So if you had an aperture of f/4 on a 50mm lens to find the width of the aperture hole
