What is ISO? Simple guides to understanding ISO

What is ISO? | ISO in Digital photography

ISO is one of the three main components of a camera(shutter speed and aperture are the other two). This three-component determines what will happen to the images you shot. Fortunately for you, we have put together this simple explanation to understand what happens when your camera’s ISO is changed and how it affects your images.

What is ISO?

Most fundamentally, ISO is a camera setting that brightens or darkens a photo. When you increase your ISO, you will get a brighter image than lower ISO value. This means higher value ISO in a darker atmosphere will help brighten your image with the right aperture and shutter speed settings.

Furthermore, Higher ISO number has certain do and don’t. A photo taken with higher ISO value tends to have Noise, which might render the pictures useless. Therefore, brightening the image by ISO is always a trade-off. Increasing ISO value should be a secondary option if you cant increase the image brightness via aperture or shutter speed.

ISO in Digital Photography

In Digital Photography ISO determines the amount of light the image sensor receives. The same principles apply to film photography.

The lower your iso value the less sensitive your camera is to light therefore eliminating grain.

A higher number will make your camera more sensitive to light allowing usage in a darker environment. The consequences of higher ISO as said earlier will bring about grain in your picture. Although some latest DSLR camera shoot fine images in a darker environment.

Each camera has a different range of ISO values that you can change to at any time

Common ISO value listed below:

ISO 100 (low ISO), ISO 200, 400, 800, 1600, 3200 & ISO 6400 (high ISO)

In Addition, when you double your ISO speed, you are increasing the brightness of the image twice as much. So, the photo at ISO 400 is twice as bright as ISO 200.

ISO & Exposure

You need to understand the do and don’t behind ISO speed. It’s about how much light is available and what you want to capture. Shooting at a low ISO gives us the best quality and the least amount of noise/grain, which is why its always better to shoot at a lower ISO speed.

ISO is a little more complicated than the sensor or film is to light. it’s a number that relates to how much light you get in your scene.

What you want to capture determines the value you use. When taking outdoor photos during summertime, you should use ISO 100 as there is plenty of light. If you take a photo inside, this value may be ISO 800 or higher.

One of the best ways to describe the use of ISO in digital photography is to use exposure triangles. This triangle can help you capture the perfect performance.

You can snap anything, anywhere, using three interchangeable zones that control the light.

Low vs. high ISO noise visibility

An example of an image shot with different ISO is shown below. Note the noise level (grain and spot color) in the images:

The difference is obvious – the ISO 3200 image has more noise than ISO 100 (I made it brighter at longer shutter speeds instead). Therefore, you should avoid high ISOs whenever possible, only use them where its the only option.

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How to choose ISO

However, there are cases where it is not possible to achieve optimal performance without raising the ISO. The most obvious example of this is low-light landscapes, especially inside the home. Other situations where you need a higher ISO are when you need to capture action (which requires faster shutter speeds) or depth of field (which needs small aperture). In cameras with larger sensors, ISO often increases significantly before the image quality is affected by the shutter speed or aperture value you desire.

How to change the iso

Changing ISO on cameras are different from one another. Let’s show you how to simply change ISO.

To get started, from your camera settings, select the ISO settings. switch from Auto to manual mode.

For mirrorless cameras and entry-level DSLRs, pressing the button labeled ISO will open up ISO mode where you can quickly change ISO speed. Select the desired value or set it to Auto.

For high-end DSLR cameras, it has a dedicated ISO button as said earlier. Press one of the wheels to change its ISO setting.

some cameras may have a dedicated wheel that already has different ISO settings. some cameras make things much easier, having a dedicated wheel which detects different ISO settings automatically.

It’s always advisable to know how to quickly change your ISO value, especially for wedding photographers, Sports, etc.

Here are some common conditions that can affect how you choose ISO:

  • If your subject is moving forward and you’re still trying to stabilize the speed, a higher ISO will allow faster shutter speeds.
  • If you are using a tripod to stabilize your camera, you can usually get out at a slower shutter speed, which allows you to use less ISO. However, the tripod does not help you stabilize the subject’s movement.
  • If you are shooting an image that does not require a large depth of field, you can increase the aperture (to allow more light) and using a lower ISO number. You should know that different lenses have different maximum aperture values, however, not all lenses provide the same amount of light.
  • If you are shooting with an external flash or light setup, you can always use a low ISO setting.
  • In particular, the noisy features of a high ISO setting can give your photos a vintage look, although it is very good for post-processing.

Minimum noise and maximum image quality

  • You should know that the High-ISO image looks great on your camera’s LCD screen, but it may have noise after printing or viewing on a computer screen.
  • Using ISO below 400 is the best way to capture quality images. However, as shown above, that is not true. Sometimes, you might find yourself shooting in a darker atmosphere where you have to raise your ISO above 400.
  • If you want to shoot at a higher ISO, you may want to take some time to find and adjust your camera’s noise reduction settings, because minimizing it can help save details in your images.
  • ISO of 400 values and below are to be used where there is enough light. ISO below 200 is not meant for a dark environment.
  • Furthermore, using a faster shutter speed setting is equivalent to shooting in a dark area because you are simply limiting the amount of time your camera should be sensitive to light. This means, on some occasions such as sport & motion photography, a high ISO is needed.

Get the most out of your camera ISO using this four simple

  • Choose the right aperture setting that will give you the depth of field you want.
  • Set your ISO to its original value (100 or 400) and enter your shutter speed in any setting that provides adequate exposure.
  • To get rid of blur image use fast shutter speed and gradually increase your ISO.
  • In addition, if your ISO setting is too high and probably still able to open up your aperture, reduce the ISO and open up your aperture to get more light into the camera sensor.

In Conclusion, understanding the value of ISO for different environments is the key to a quality image.

Olajide Towoju
Olajide Towoju

Towoju Olajide is a technology writer who covers topics ranging from consumer tech to the latest developments in artificial intelligence. Born and raised in Nigeria, Towoju developed an early fascination with technology that led him to pursue a degree in Computer Science. After completing his studies, he worked as a software developer for several years before transitioning into tech journalism.

Towoju's work has been featured in various publications, including TechCrunch, Wired, and The Verge. He is also a regular contributor to several technology blogs and podcasts, where he shares his insights on emerging trends and breakthroughs in the tech industry. In addition to his work as a writer, Towoju is an avid photographer and enjoys capturing the beauty of nature and wildlife in his spare time.

Over the years, Towoju has written several books on technology and its impact on society. His writing has been praised for its ability to break down complex concepts into simple, easy-to-understand language. Whether he's exploring the latest advancements in AI or discussing the future of smart cities, Towoju's goal is to make technology accessible to everyone.

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