What is Aperture in Photography?
Aperture refers to the opening inside your lens that lets light pass through to your camera’s sensor. It’s measured in f-stops (like f/1.8 or f/8), and it directly affects two major things: how bright your photo is, and how much of it is in focus. A wide aperture (small f-number) lets in more light and creates shallow depth of field. A narrow aperture (larger f-number) lets in less light but keeps more of the scene sharp.
How Aperture Affects Light and Exposure
Think of aperture like the pupil of your lens — the wider it opens, the more light hits your sensor. A setting like f/1.4 or f/2.0 is great for low-light situations or indoor shooting without cranking up ISO. On a bright day, you’ll likely want to stop down to f/8 or higher to avoid overexposure. Aperture is a key piece of the exposure triangle, working alongside shutter speed and ISO.
Aperture and Depth of Field Go Hand in Hand
Want a creamy background blur? Use a wide aperture. Want everything tack sharp from front to back? Go narrower. Aperture controls how much of your scene is in focus — and it’s one of the most creative tools in your kit. Portrait shooters often lean into wide apertures like f/1.8, while landscape and architecture photographers usually stick with f/8 or f/11 to keep every detail in check.
The Weird Thing About F-Stop Numbers
Here’s where it trips people up: the smaller the f-number, the larger the opening. f/1.4 is wide open. f/16 is a pinhole. It’s inverse logic, but you get used to it. And the f-stop scale isn’t random — each full stop doubles or halves the amount of light. Learn it once, and you’ll never shoot on guesswork again.