What Is Aperture In Photography? A Comprehensive Guide

By Indeed Editorial Team

Published 26 May 2022

The Indeed Editorial Team comprises a diverse and talented team of writers, researchers and subject matter experts equipped with Indeed's data and insights to deliver useful tips to help guide your career journey.

When starting photography, some of the first concepts you learn comprise of what is aperture, ISO and shutter speed. Among these, the aperture is perhaps the most important. Knowing how to choose the correct aperture is useful because it affects not only the exposure of your photograph but also the depth of field and sharpness. In this article, we discuss what aperture is and how it affects photographs, plus provide tips for selecting the correct one for your photograph.

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What is aperture in photography?

If you have just begun photography, you may benefit from knowing the answer to, 'What is aperture?'. The aperture is an opening that controls the amount of light that can pass through the camera lens. If the opening is wide, more light can pass through the lens and hit the sensor, making your photograph brighter. If the opening is small, less light can pass through, making your photograph darker. Several opaque blades, known as the diaphragm, form the aperture mechanism that controls the amount of light.

Photographers measure aperture in terms of stop numbers known as focal-stop or f/stop numbers, where the f stands for the focal length of the lens. The f/stop number is the ratio between the focal length and the effective aperture diameter of the lens. The lower the f/stop number, the bigger the aperture, which means that more light can pass through the lens. The higher the f/stop number, the smaller the aperture, so less light passes through the lens. The most commonly used f/stop numbers are f/1.4, f/2, f/2.8, f/4, f/5.6, f/8, f/11, f/16 and f/22.

The exposure triangle

Together, the aperture, ISO and shutter speed form an important concept of photography known as the exposure triangle. According to the exposure triangle, a balance between these three components is a requirement for taking a photograph with perfect exposure. Choosing the correct metering mode frequently leads to an exposure value (EV) of zero. If you modify any of these three parameters after achieving the correct balance, it may be necessary to adjust the other two settings as well to maintain an EV of zero.

How aperture affects exposure?

In photography, exposure refers to the overall brightness or darkness of a photograph. It is the amount of light that reaches the camera's photographic film or electronic sensor. With a fixed ISO and shutter speed, a wider aperture or lower f/stop value means more light enters the camera, which results in a brighter photograph. This setting is useful when taking photographs at night or in a dark setting.

A narrow aperture or higher f/stop value limits the amount of light that can enter. This setting is good for taking photographs in the sun or in a bright indoor setting. It is important to note that while aperture affects exposure, it does not work alone in achieving the correct balance. Aperture, shutter speed and ISO all work together to determine the exposure of a photograph.

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How aperture affects depth of field?

Another critical aspect of photography that the aperture affects is the depth of field. Depth of field is the distance between the object nearest to and farthest from the camera. This is the area that appears sharp in the photograph. Sometimes, the background has a thin or shallow depth of field, meaning it is totally out of focus. In other photographs, it is large or high, which means that both the foreground and background are sharp.

The wider you keep the aperture, the shallower the depth of field becomes. If you want to blur out the background of your photograph, select a small f/stop value in your camera's settings. Choose a higher f/stop value to make the aperture smaller and increase the depth of field of your photograph.

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How to choose the correct aperture setting?

There is no single answer for what is the best aperture setting. Generally, most cameras perform well around the middle of their aperture range, but the right aperture setting is different for different photographs. Below are some factors that you may want to keep in mind while selecting the aperture:

1. Consider your subject

It can be useful to determine beforehand what you want the viewer to focus on in the photograph. For example, in a portrait, you may want the subject to stand out so that the viewer focuses only on them. You can do so by reducing the depth of field by widening the aperture of your lens.

2. Determine how much detail you want to focus on

A shallow depth of field allows you to blur out the background and focus on your subject. In certain cases, by doing so you may not be able to work with different compositions or include additional elements that could make the photograph more appealing. You may want to consider if you want to add any additional details that can help you add to your subject and choose a narrower or wider aperture accordingly.

3. Consider how much light is available

Different surroundings have different light. You may want to adjust your aperture accordingly to ensure that your photograph has the right exposure. For example, in low-lit surroundings, you may want to widen your aperture so that enough amount of light falls on the sensor. You may also want to slow down the shutter speed or increase the ISO value to ensure an exposure value of zero.

Choosing aperture settings based on situations

Below are suggested aperture settings that you may want to consider based on the type of photograph you want to take:

Scenes with extremely low lighting

In settings with extremely low lighting, instead of using the built-in flash, you can use the widest aperture setting your lens has. You can also set the ISO higher, depending on the lighting level. Using a wider aperture allows you to capture the scene without a flash and avoids washed out faces and red eyes.

Fast-paced indoor action

Fast-paced indoor action includes indoor sports events such as indoor hockey and basketball. The lighting may be reasonable but not good enough to capture the motion without blurring the photograph. Using a wide aperture with a fast shutter speed can help you shoot the action without motion blur in the given light conditions.

Landscapes

When photographing landscapes, you want to focus on everything in the shot, including the foreground and the background. This requires a larger depth of field. A narrow aperture or higher f/stop value can offer you more depth of field throughout your shot. Setting the value to f/11 is a good starting point for finding the correct depth of field for a landscape photograph.

Brightly lit outdoor settings

In brightly lit outdoor spaces, a fast shutter speed may still lead to overexposure of your photograph. If there is a lot of light, choose a small aperture or a high f/stop value. The small aperture limits the amount of light that enters the camera, which allows you to use a slower shutter speed and prevents overexposing your shot.

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Moving objects in nature

Trying to capture motion outdoors, such as in water or fast-moving clouds, is challenging with a regular aperture setting. This is because it is hard to slow down the shutter speed enough to generate motion blur at bigger apertures. In this case, using a small aperture setting (high f/stop value) along with a tripod can help capture moving objects.

Macro photographs

Macro photographs are very close-up shots, usually of very small things and organisms, such as insects, where the subject of the photograph is either life-size or larger Macro photographs tend to lose focus at regular and even small apertures. Using the smallest aperture setting available allows you to capture even the tiniest details of your subject without losing focus. Taking macro photographs may also require a slower shutter speed and a tripod.

Backgrounds with a lot of activity

Backgrounds with a lot of activity can distract the viewer's attention from the subject, making your photograph look cluttered. You can blur out the background by using a larger aperture, which creates a shallower depth of field. A larger aperture can help you do so, and this can help viewers to focus on the subject of the photograph.

Portraits

It is also important for the subject to be the focus of portraits. Again, creating a shallow depth of field by using a larger aperture can help you blur out the surroundings. This makes the subject of your photograph sharper than the background and allows the viewer to focus on it.

Bokeh

Bokeh is a soft out-of-focus blur in a photograph that looks aesthetically pleasing. You can create this by selecting a wide aperture value. A high value would be better for creating a bokeh effect. To create a visible bokeh, you can increase the distance between your subject and background by bringing the subject closer to the camera. This makes the depth of field shallower and the bokeh more visible. Trying different f/stop values can also help you achieve your desired effect.

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