A Beginner’s Guide to ISO, Aperture and Shutter Speed

I will start this guide by saying that cameras are complicated, and it takes quite some time and effort to learn how they work inside out. When I first bought my camera, I had no idea what ISO, Aperture and Shutter Speed was, which are the most important things to know before starting taking pictures. 

In the beginning, I was so frustrated that the camera didn’t capture what I could see through the camera’s viewfinder. So what did I do? I went to a beginners class by NIKON, took notes, and started to research about how the settings on my camera worked. When I got the hang of it, I began to be able to capture some amazing pictures. 

In this post, I will teach you about the three essential elements for photography. Get ready, here is a Beginner’s Guide to ISO, Aperture and Shutter Speed!

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Understanding ISO

What is ISO?

To explain ISO as simple as possible, ISO is the level of how sensitive your camera sensor is to light. A higher ISO number makes the sensor in your camera more sensitive to light, and a lower ISO-number makes it less sensitive to light. 

This means that a low ISO-number suits in good lighting conditions, and a high ISO number when the light is poor. You may, therefore, need to increase the ISO-number in dark environments, so the camera’s sensor can be able to register enough light to get a correct exposure of your photo. 

For example, if you are shooting inside your house at night and without your cameras flash, then it could be a good idea to select a higher ISO-number such as ISO 400, depending on the available light inside your home. A bright summer’s day outside, you will foremost not have to use a higher ISO-number than ISO 100, as you are shooting in good lighting conditions. 

If you are shooting in poor lighting conditions, like at a concert, then you may have to use a high ISO-number to be able to take the picture. 

Why you should avoid using high ISO

Sure, it may feel very comfortable to use a high ISO-number to shoot in dark environments. But there’s a catch. When you are shooting with a high number of ISO, the picture will contain more noise than an image with a low ISO-number. Then you might wonder what noise is in a photograph? Noise is randomly scattered color dots or unevenly colored patches in areas of your photo which should be smooth and evenly colored. The noise is usually seen in dark shadows and cleaner surfaces such as a soft and blue sky.

With that said, always try to have an as low ISO as you possibly can if you are looking for good image quality, as the quality will be so much better then if you use a high ISO-number.

ISO Practice

Before you read forward about Aperture and Shutter Speed, it’s a good idea to experiment a little with the ISO on your camera. So you understand how it works, where to find the ISO setting and how you change the ISO-number (you can look that up in your camera manual).

When you have figured that out, take some pictures of a motive in both good and poor lighting conditions and change the ISO number from low (100) to higher and higher ISO-numbers. Then make sure to look at the results and compare the pictures.

Understanding Aperture

What is Aperture?

To simply put what Aperture is, it’s a hole within your camera’s lens. Through this hole, the light travels to hit the camera’s sensor. Through your decision of the size of the aperture (hole), you will affect how much light that will reach the sensor in your camera. The larger the aperture (hole), the more light will hit the camera’s sensor. Quite logical right?

How does the Aperture work?

The aperture is to be found in your lens, and it’s a hole that is built up of a number of moving blades. When shooting a picture, you can set the size of the aperture (hole), and control the amount of light that hits the sensor. The aperture is defined as an F-number on your camera, often displayed both in the cameras viewfinder and on the screen of your camera body. 

The aperture’s F-number (size of the hole) indicates the amount of light that is let through to hit the sensor. These different aperture numbers are also known as F-Stops and run in a series of numbers. The first times that you look at these numbers you might feel a little confused as they can be a bit difficult to understand. But don’t worry, in time you will understand the aperture from inside out. 

The aperture number are often specified by an “F” before the actual number, and runs from F/1 up to about F/32 as following numbers:

1, 1.4, 2, 2.8, 4, 5.6, 8, 11, 16, 22, 32. 

These numbers represent the whole steps of the aperture on your camera. The numbers may also vary as some cameras can choose the aperture number in half or thirds steps. The characteristics of the chosen aperture number will affect your image significantly, something that you will learn soon. 

Therefore, it is very important to know what the aperture numbers mean, and what they do to a picture before you’re about to snap some shots. For each step between the numbers, from left to right in the number series above, the hole in your lens lets exactly half as much light into your camera as it did before.

Let’s say that your given environment requires an F of 8 (F/8) and your camera is set on F/11, then it means that only half of the light that this picture needs to get a correct exposure is released into your camera. The result of this would be an underexposed (too dark) image. Would you instead have an aperture of F/6 and the picture requires F/8, the photo would be overexposed (too bright) as you have let in too much light to hit the sensor.  

This is important to add to your mind:

• A LOW number gives a LARGE aperture (hole), which lets through much light. 
• A HIGH number gives a SMALL aperture (hole), which lets through less light. 

The Aperture controls the Depth of Field

The right aperture for your picture does not only help your image to get a correct exposure, it does also control the depth of field in your photos. The depth of field in your images is depending on what aperture you have set on the camera and regulates your foreground/background to be either sharp or blurry. This is called depth of field, and by learning and understand how the aperture affects your pictures, you will develop your photography skills.

The depth has no sharp boundaries where the motive goes from sharp to blurry in one step. The transition takes place gradually, both in front of and behind the motive that you focus on. The better you understand the relationship between aperture and depth of field, the more you will be able to use that knowledge in a creative way to help improve your skills as a photographer. In fact, this will be one of your sharpest tools when you are creating an interesting image. 

Important to remember about the connection between aperture and depth of field:

• A LARGE aperture (low F-number) gives a SHALLOW depth of field (blurry)
• A SMALL aperture (high F-number) gives a DEEP depth of field (sharp)

For example; you are shooting a photograph with focus on a person that are standing front of a forest. If you use a LARGE aperture (low F-number), the background will be shallow (blurry). If you instead use a SMALL aperture (high F-number), then your background will be deep (sharp). 

When should I use a shallow depth of field?

When you want to isolate your motive, then it can be a good idea to use a shallow depth of field (a low F-number).  

A few examples of when you could use a shallow depth of field:

• When you want to separate your motive from a messy background
• When you are shooting a portrait and wants the motive to stand out from the background
• When shooting animals, sports, and small details is larger contexts

The shallow depth of field can be used in countless situations, and there is only your imagination that can limit that. Never be afraid to experiment with a shallow depth of field, the results can be amazing!

When should I use a deep depth of field?

Landscape photography is a classic example of pictures that requires a deep depth of field. With a small aperture (high F-number), the picture will be able to be sharp from the foreground all the way to the background. A deep depth of field gives you a nice overlooking view of a landscape where you will be able to see all its beautiful details. As the whole picture will be sharp, the image will give us a perspective that is much similar to the way that we experience the landscape view in real life. Those pictures that not have obvious motives and those who are relatively calm for the eyes to look at are perfect examples of images that can be shot with a deep depth of field. 

Aperture Exercise

Even though you might know how the aperture works and how it affects your pictures just by reading this guide, it’s still important to practice before you head out to shoot. Change the aperture and see how it affects the exposure and the depth of field of your pictures. Think about how the emotion/feeling changes when your pictures change step by step. Remember that the depth of field is one of the best tools when it comes to creating interesting pictures.

If you are facing each picture and are thinking about what kind of aperture you should use to affect the depth of field, then you’re starting to think like a real photographer. 

Understanding Shutter Speed

What is Shutter Speed?

Now when you have learned how the ISO and aperture works, then it’s time to go on to the third element. This third element controls the flow of the light that hits your camera’s sensor – the Shutter Speed. 

The shutter is to be found between the sensor and your lens and is best described as a door. The speed of the shutter (door) is up to you to decide how long it is going to be open for light. The longer you have the shutter open, the more light will hit the sensor. The shorter time that you have the shutter open, the less light will hit the sensor. The time that you hold the shutter open is called shutter speed. 

When it comes to shutter speed, there is no standard speed to make the perfect images; you simply have to learn and adjust to the environment that you are shooting in. 

Select the appropriate Shutter Speed

The Shutter Speed is usually changed with a wheel or a button on the camera’s body. Your selected shutter speed is often displayed in both the viewfinder and on the screen of your camera. Most DSLR cameras has a shutter speed that varies from 30 seconds to 1/2000 (and even higher) part of a second in the following steps:

30”, 15”, 8”, 4”, 2”, 1”, 2, 4, 8, 15, 30, 60, 125, 250, 500, 1000, 2000, and so on…

This series of numbers are corresponding the “whole” steps of the shutter, but can also be chosen in half or third steps. From the left side of the number series above, the first numbers has a symbol (“). This symbol (“) means that this number is a whole second, so for example, the number 30” means that the shutter will be open for 30 seconds. On the right side of the series of numbers this symbol disappears, and that means that the numbers is a part of a second. So, 250 implies that it is a 1/250 part of a second. 

For each step that you take in the right direction of these numbers, the shutter speed will release in half as much light as in the step before. These steps of the shutter has the same effect as the steps of the aperture when it comes to the amount of light that hits the sensor. For example, if your picture is to bright (overexposed) when you have set the shutter speed to 60, try to set the shutter speed setting to 125, which will make your image darker as the shutter lets through less light. 

The Shutter Speed controls motion blur and the freezing of a movement

Freeze movements with a fast shutter speed

If you are shooting a subject that are moving, for example a bird, then you will have to choose a fast shutter speed to freeze the moment. If you have a longer shutter speed while shooting a photograph of a moving motive, then the motive will be blurry. This is calls motion blur, and if it’s not used as a fully aware effect, it usually ruins the image. 

The best way to avoid motion blur if you want to freeze a moment of movement is to select a shutter speed of 1/500 or faster depending on the available light. A fast shutter speed is very useful if you want to take a sharp picture of, for example, a flying bird, a marathon of running people or a car that is driving by. You can even freeze those moments that the eye can’t see, such as falling water droplets with perfect clarity. 

Experiment with longer shutter speeds and motion blur

Sometimes a long shutter speed can be the perfect decision, even though the motive is in motion. If your motive is in motion and you have set a long shutter speed, it will create motion blur. When using a long shutter speed deliberately, it can create really cool effects in your photos. 

For example, you would like to obtain a picture that shows how the water of an waterfall actually flows or turning a river or lake with movement crystal clear. Then a long shutter speed is a crystal clear choice.

A classic example of great pictures with deliberate motion blur is photographing cars at night. When shooting a road with cars that are passing by at night, it will create long lines of the lights that the cars emit. 

Avoid Camera Shake when you are shooting with a long shutter speed. 

When you are shooting a picture with a long shutter speed, it’s very important to know that you have to keep the camera completely still to avoid blur in the image. It is impossible to hold a camera with your hands perfectly still while the shutter is open, and that affects the sharpness in your pictures. This is called camera shake and is one of the most common causes of blurred images. To avoid getting camera shake into the picture while shooting with longer shutter speed, use a tripod. 

If you don’t have a tripod, you can always try to lean against a wall while you’re shooting, or place your camera on a stable place like a table, chair or whatever else you can find at your location. Also, make sure to push the trigger of the camera gently but firmly to avoid further camera shake. 

Shutter Speed Exercise

Experiment with the shutter speed to see what your camera can do. Start with a shorter/faster shutter speed and take photos of dripping water from your kitchen tap. Then, set your camera to a longer/slower shutter speed and photograph a friend or a family member who is walking around in front of the camera and see what happens.