What is ISO in Photography? Using a camera on manual for the first time can be scary, especially when you don’t know the settings. Your camera settings are controlled by three variables, shutter speed, aperture and ISO.

ISO is your camera’s sensitivity to light, this is essential to understand when shooting on manual.

ISO plays an important role in the exposure triangle. The exposure triangle is used to generate a correctly exposed photograph.

What is ISO in photography?

To begin understanding ISO you need to know that when the camera is put to its lowest sensitivity (commonly known as ISO 100), the sensor is least sensitive to light.

When we move the sensitivity further up the ISO scale to ISO 800 for example, the sensor is increasingly sensitive to light. But more noticeably the low light capability and quality of the sensor have decreased.

Similarly, moving to higher sensitivities will increase the noise in your images, giving them a “noisy” look when shooting in low light. However, for most images, you will have no issue using a range of sensitivities to get the quality and exposure you are after.

Photographers should be aware that the more sensitive a camera sensor is to light, the more challenging it is to record in darker environments.

Here is a guide that I have made to help you understand what ISO is in photography.

How to use ISO

ISO is typically a number between 100 and 1600 (in most cameras) or 6400 for low light conditions.

I usually begin by setting my ISO to 100 and keeping it as low as possible for low light photography as the noise will be less noticeable when photographing in low light at a lower ISO.

Keeping your ISO around 100 and 1600 will barely produce any noise in your photograph.

When photographing concerts or gigs, you will want to make sure you keep your ISO around 800 as you will need to keep any noise to a minimum to make sure your photographs are of high quality.

I personally try to keep my ISO as low as possible when photographing at music venues.

I use ISO 1600 or 3200 only if I have to, depending on the lighting. The noise within the photograph at ISO 1600 is just about tolerable and unnoticeable for most.

While ISO allows images to be brighter, sometimes the better option is to change your shutter speed or aperture in order to let more light in; Doing this avoids ISO ruining the quality of your photographs.

Where possible, in low light conditions such as night time, you can resort to using a tripod and slowing down the shutter speed to ensure the shot stays sharp and avoids being noisy.

Different cameras are capable of reaching different ISO limits, newer models and mirrorless camera’s tend to cope better at a higher ISO, meaning that they can be great at shooting in low light conditions.

What Does Noise Look Like?

Noise is produced when your ISO is raised, this destroys the quality of the photograph. Noise looks like little small dots within the photograph which results in the photograph looking grainy and gritty. For some this aesthetic has become fashionable but this aesthetic is not suited for everyone.

Here is a zoomed in, unedited photograph, from a gig with very little light.

Examples Of ISO Settings

Within my profession, the majority of my time is shooting in low light. As a music photographer, it is always challenging to use the lighting to your advantage. Dealing with consistently changing light means that I can go through many settings and ISO settings through one performance.

For the sake of this article I have not edited these photographs in anyway. What you see is uploaded straight from the camera with no adjustments.

ISO 3200

The photograph above is taken at 3200 ISO. As you can see there is only little noise in this photograph. The noise is only noticeable if you zoom in.

ISO 4000

When zoomed in, you can begin to notice some noise within the photograph.

ISO 8000

To the trained eye the ISO is too high in the photograph and as a result is producing too much noise.

When should you change ISO?

Every camera has a different ISO capability. With high sensitive sensors, you will need to know when to take the shutter speed down when shooting.

DSLR cameras have an option to adjust ISO directly in the menu. Having this provides quick access to the ISO setting.

Most cameras come with a minimum and maximum ISO setting.

The minimum ISO you should shoot at is around 100 (50 for some cameras), and the maximum ISO setting will be around 6400 but some cameras can reach 51200.

If your ISO level is too high, you will struggle to get good images and keep the high quality. You may get some overexposure in dark shadows, and overexposed highlights.


To put it simply, the higher the ISO number the more sensitive your camera is to light; resulting in your photographs being brighter. Raising your ISO to a high number will introduce noise to your photographs. Noise destroys the quality of your images.

Leave a comments below if you have any questions or just share a thought.