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Photography 101: ISO

ISO is one of the three fundamental pillars of manual photography—the other two being aperture and shutter speed. We’ve already covered those two in our Photography 101 series, so today, we’re explaining ISO. 

ISO is perhaps the most confusing setting for many new photographers, but understanding it is essential to achieving crisp photos with the proper exposure. Check out our guide below to learn everything you need to know about ISO and how you can become proficient in it. 

What is ISO?

ISO is what makes a photo brighter or darker. When you increase your ISO setting, you’re making the picture noticeably lighter— and darker when you lower it. This makes it an essential setting for achieving the correct exposure in low lighting situations. What ISO setting you use also allows you to be more flexible with your shutter speed and aperture. 

ISO Values

Every camera has its range of ISO settings, but there are some common values you can expect to see. These include:

ISO 100 (low ISO)

ISO 200

ISO 400

ISO 800

ISO 1600

ISO 3200

ISO 6400 (high ISO)

ISO and Noise Visibility

Getting ISO down isn’t just about choosing the right level of brightness. It’s also crucial to avoiding noisy photos. But what is noise? Just like sound has auditory distortions, photos can experience visual distortions. 

It’s common in digital photography and looks like colorful pixels and can even look like the grain you see in film photography. Digital noise can make the details of your photos look fuzzy and distort details, making it something many photographers try to avoid. There are different reasons why an image might come out “noisy,” including higher ISO settings, long exposures, and your camera’s sensor size. 

Base ISO

Understanding what your camera’s ISO settings are isn’t enough to get it down. You should also know your camera’s base ISO. This is the lowest native ISO setting on your camera, and using it allows you to get the highest quality images with the lowest amount of noise (more on that below). 

Choosing the Right ISO

Even though high ISO generally means your photos are more likely to have noise in them, that doesn’t mean you should disregard them. Depending on your location and lighting, you’ll need a higher setting to get the best results. Here are some different situations when you want to use either a low ISO or high ISO setting. 


Lower ISO settings come with less noise, so sticking to these options is generally ideal for getting the clearest images. For that reason, try to use an ISO of 100 or 200—or stick to your base ISO—whenever possible. Even in low-light situations, you can adjust other settings like your shutter speed to achieve more brightness. 

High ISO

The higher your ISO, the more noise you can expect to see in your image. That doesn’t mean you should completely steer clear of higher ISO’s, though. Many low-light situations will call for a higher ISO, but higher settings will also help combat motion blur. 

How to Change ISO

Like the ISO values, changing the setting on your camera will vary depending on the make and model. Still, there are some typical ways of changing it. 

  • First, get out of automatic shooting and manual mode, aperture priority, shutter priority, or program.
  • If you have an entry-level DSLR or mirrorless camera, you’ll probably need to go to the menu.
  • Higher-end cameras usually have a dedicated ISO button that you can press while turning the wheel to adjust it. 
  • Some cameras have a dedicated wheel for changing your ISO settings. 

Remember always to take the time to learn the ins and outs of your camera to get this down. If you don’t see a place to change it right away, check out your camera’s manual for instructions. 


ISO might be the most misunderstood out of the other basic settings, so to help you get a solid grasp of it, we’re answering some of the most frequently asked questions.

What Does ISO Stand For?

Now that you know what ISO does when it comes to photography, let’s break down the acronym since many curious photographers want to know. ISO stands for International Organization of Standardization. 

So what does this have to do with photography? In 1974, the two film standards, ANA and DIN, were combined, and to get the world on the same page, they were then referred to as ISO. This isn’t necessary to know for getting your ISO settings down, but it’s a common question. 

Is ISO the same as exposure?

ISO is not the same thing as exposure, but it is part of the “exposure triangle,” including aperture and shutter speed. So to get the perfect exposure in your photos, you have to find a balance between all three based on where and what you’re shooting. 

Is ISO the same as sensor sensitivity?

Many websites and publications have said ISO acts like a camera’s sensor sensitivity, but that’s not true. Digital sensors only have one sensitivity, no matter what ISO setting you’re on. The reality is that ISO is more like a map that tells your camera how bright the output should be depending on the exposure. 

Is ISO the same as brightening your photos in editing?

Yes, you can change the brightness settings of your photo in programs like Photoshop and Lightroom, but that doesn’t mean it can replace getting your manual ISO settings. While it’s similar in the sense that brightening a photo can make the noise more noticeable, 

However, adjusting the ISO directly on your camera will always provide better image quality than simply changing it on your computer. This ultimately translates to crisper images to edit. 

Mastering Your Camera’s ISO

Like any other setting, the best way to master ISO settings is to get out there and practice. Try shooting in a range of situations that feature different types of lighting to get an idea of the brightness levels and amount of noise you see. As you become more familiar with the varying results, you’ll be more confident knowing what setting is suitable for any picture you’re taking! 

Don’t forget to learn more manual shooting basics with Anthology’s Photography 101 series. 

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