What is aperture?

What is aperture and how can you use it correctly to create brilliant photographs and video footage? Here's everything you need to know about aperture.

• What is aperture?

• What is the correlation between aperture and the camera lens you use?

• How is the aperture controlled in the camera?  

• How do aperture, ISO and shutter speed work together?

• How to use Aperture priority or AV mode on a DSLR?

• How to use aperture while creating videos from a DSLR?

• How to use aperture while creating videos from a smartphone camera?

What is aperture?

Aperture is the opening in the lens through which the light passes to enter the camera onto the camera sensor. It works just like the pupil of a human eye. When the light is dim and low, the pupil allows more light to pass through. When there is too much light, our pupils shrink to allow little light to pass.

Simply explained, the camera lens works the same way our pupil does.  

Aperture is identified by a f/number, often called a f/stop. f/stop is the ratio of the focal length to the diameter of a camera lens’s diaphragm. It is also known as the focal ratio. f/stops indicate how open or close the aperture is.

A smaller f/stop means a larger aperture while a larger f/stop means a smaller aperture. 

What is the correlation between aperture and the camera lens you use?

Aperture not only decides the amount of light entering the camera but also has a huge impact on the depth of field.

A larger f/number such as f/16 will bring the foreground as well as background into focus while a small f/number such as f/1.4 will focus either on the background or the foreground objects while blurring everything else.

Every camera lens has an aperture limit of how large or small the aperture can get. The camera lens has its f/number limits specified on top of the lens. The maximum f-number of any lens indicates the speed of the lens.

Prime lenses have a fixed focal length hence they cannot zoom without physical movement from the photographer.

On the other hand, Zoom lenses allow you to zoom in while the aperture gets smaller as the focal length increases. Zoom lenses are also called ‘variable aperture lenses’. 

How is the aperture controlled in the camera?  

Controlling aperture needs to be mastered in manual mode to achieve perfect results.

Once your camera is in manual mode, you can use the camera’s program controls to navigate through the various f-stops compatible with your lens.

Alternatively, if your camera lens has an aperture ring you could shift the aperture ring on your lens to your desired setting. 

How do aperture, ISO and shutter speed work together?

Aperture, ISO, and shutter speed are interlinked, changing any one of these will affect the other.

It can be challenging for beginners to balance these initially so one can start with the aperture priority mode (AV) where the camera decides the shutter speed and ISO automatically.

A larger aperture that allows more light into the camera also enables you to use a faster shutter speed and a lower ISO value. This removes the chance for grainy pictures or motion blurs to appear.

Faster shutter speeds can help you to capture moving objects very easily while slower shutter speeds will get you sharper images and are useful for night landscape photography.

How to use Aperture priority or AV mode on a DSLR?

The Aperture priority or AV mode is a great way to develop an understanding of how your camera works. Use it as a training tool while you're in transit before you are confident enough to use Manual mode to take perfect photos and videos.

The moment you start using aperture priority mode, scroll through the aperture f/stops to understand how your aperture works as well as its limitations.

Once you’re done with choosing your aperture, you need to lock your ISO on AUTO by scrolling past all the ISO options and selecting AUTO ISO. 

Here's a useful tip: if you're taking a portrait and want the background to blur, you can choose to use the 50mm prime lens which offers an aperture of f/1.8.

How to use aperture while creating videos from a DSLR?

Looking to film videos from your DSLR camera? If you've tried automatic mode, you may have seen that your camera can sometimes experience "confusion" around what to light properly as you record video indoors and outdoors.

That's where Manual mode can take away the pain by giving you full control of the aperture while you follow your subject around.  

How to use aperture while creating videos from a smartphone camera?

Filming videos from a smartphone camera is different from using a professional DSLR camera. Smartphone cameras come equipped with a built-in PRO mode and this creates room for a lot of experimentation! You can use ND filters or moment lenses as well on your smartphone as an attachment to get a variety of aperture values.

Now that you're familiar with aperture, why not experiment with it?

If you're looking to learn more about video production, check out our resources such as what is the rule of thirds and what is aspect ratio. Level-up your video expertise by reading our video glossary.