What is Aperture?

To put it simply, photography is all about the capture of light. The aperture is one of two primary components that directly control how a camera captures light (the other being shutter speed).

Definition of Aperture

The aperture's dimension will change in accordance with the aperture settings, namely f/stop values. The size of the aperture is inversely proportional to the f/stop value itself (that is, the larger the f/stop value, the smaller the opening of the lens, and vice versa).

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When you combine aperture with the appropriate shutter speed, you have direct control over a photograph's exposure. This allows you to accurately capture the correct amount of light to reproduce an image as seen in reality.

Understanding Aperture

So what is aperture in layman's terms? Your camera’s aperture is the hole that lets the light in. All cameras have something that is called an Iris Diaphragm, which makes the aperture bigger or smaller to let more or less light in.

Your camera’s aperture has two functions. Firstly, since aperture controls how wide the lens shutter opens for, it controls how much light reaches the camera’s sensor. Secondly, it controls how much of your image is in focus. This is referred to as ‘depth of field’.

Aperture is measured in settings on your camera called ‘f-stops’, for example, f/32, f/22, f/16, f/11, f/8, f/5.6, f/4, f/2.8, f/2, f/1.4. These numbers tell you how large the opening of your aperture is.

How to Use Aperture in Practice

• A small aperture (or large f/stop value such as f/16) means that everything in the scene will be in sharp focus.

This is great for landscapes or any photos where you require a large depth of field.

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• A large aperture (or small f/stop value such as f2.8) means that the lens is wide open. The effect is that only the foreground will be in sharp focus, whilst the background will be fuzzy.

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This is useful where there are low levels of light, as the large aperture allows more light to reach the sensor. You will typically use large apertures for portraits or fine art flower photography, where you want to blur the background as much as possible.

Aperture and Shutter Speed

In considering what is aperture, you have to take shutter speed in consideration too.

Shutter speed controls how long the lens opening stays open for, and therefore, how long light reaches your camera’s sensor for the image to register. A fast shutter speed means the lens opening opens and closes very quickly, letting in a smaller amount of light. This is useful for action shots like in sport photography where you need to freeze movement. A slow shutter speed is useful for landscape photos where you want lots of light to gather for saturated color.

Every time you open your camera’s aperture by one f-stop, you’re letting in twice the amount of light, meaning you need to cut your shutter speed in half to give you the same exposure.

Think of it like driving a car with a manual transmission. You need to let the clutch out as you give the car gas. You’ll get the feel for the interplay between aperture and shutter speed as you gain experience in experimenting with the different settings on your camera.

Automatic vs Manual Settings

Depending on how much light is available in the situation you find yourself in, you can manually set your aperture, or you can let your camera take care of it automatically. Though a lot of photographers would scoff at using automatic settings, don’t be afraid to rely on them while you are still learning about photography. If you set your camera to Aperture Mode (AV), it will automatically set the shutter speed for you. If you take note what settings are applied, your camera itself can be an invaluable teacher.

Related Posts

If you have found this explanation of what is aperture helpful, you may like to visit the following pages as well:

* Beginning Photography Tips

* Digital Photography Free Tutorials

* Tips for Taking Digital Photography

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