What Is ISO and How to Use It to Perfect Your Photography

Photo of sea shell, ISO 100 vs ISO 2000, photography for beginners

Perfecting the art of taking great shots with your DSLR camera requires a lot of practice and patience. The most important lesson revolves around the basics of exposure. Light is an important criterion when it comes to photography. It not only creates texture in photographs but also defines the composition of the object and its surroundings. In other words, to take great shots, you have to understand how to use light to your advantage.

With exposure, we mean the amount of light your camera gathers while taking a photograph. One of the major aspects of exposure is ISO, and it is key to solving several exposure problems. Other aspects of exposure include aperture and shutter speed, and it is important that you understand them before you learn more about ISO.

To get you started, let’s define ISO.

What Is ISO?

In simple terms, we can describe International Organization for Standardization (ISO) as a camera setting that brightens or darkens a photo and effects light sensitivity of image sensor. This means that as you increase your camera’s ISO value, you progressively brighten your image.

Therefore, we can say that ISO can help you capture images in environments with limited light.

However, despite this setting offering an easier way of brightening images, raising your ISO too high comes with consequences. When you set ISO too high, your photo will show a lot of grain (noise), and thus might not be usable. Therefore, too high ISO trades off the quality of your shots.

Low ISO vs High ISO

Raising ISO should be the last resort- you should alter the aperture setting or shutter speed to see if it brightens your photo enough. For example, if using longer shutter speed causes your subject to become blurry, you are allowed to raise your ISO.

What Is Base ISO, and What Are the Common ISO Values?

The lowest ISO figure on your camera is what is known as base ISO. This is an important setting as it enables you to take the highest image quality with minimal visibility of noise.

Older DSLRs have a base of ISO 200, while most modern DSLRs have a base ISO of 100s. It is always recommended that you set your camera to the base ISO to get the highest image quality. However, this might not always apply, especially when you are trying to take a shot in low-light environments.

Some of the common ISO values/ISO speeds you can juggle includes;

ISO 6400

ISO 3200

ISO 1600

ISO 800

ISO 400

ISO 200

ISO 100 - this is the base ISO and the ideal setting to use

Some of the latests camera models have ISO sensativity settings lower than 100 and higher than 6400.

So, how high (in terms of ISO value) should you go?

A precise answer to this is “as high as you need for the shot you are trying to take without loosing to much of details to unwanted noise(grain).” However, since this is not a convincing answer to the above question, here is a detailed answer.

How high you should set your ISO value settings depends on three things:

1. Final output you want to achieve

Keeping in mind that ISO affects the amount of noise, color fidelity, and dynamic range of an image, you should adjust it based on the quality of the image you want to get.

If you are working for a client who wants the exact color of the subject to appear in the resulting image, you will have no option than to keep your ISO at the base ISO value. This will ensure highest color fidelity in all your images.

By keeping your ISO at its base value, you will be able to capture as much information in the highlights and shadows as your sensor allows.

2. The scene you are in

Raising your ISO allows you to use faster shutter speed (how long shutter remains open at a given setting). This means you can take better shots and avoid blurry images caused by camera shakes.

Also, if you need more depth of field, you might need to raise your ISO to allow reduction of your aperture. For example, when taking a photograph of people moving on a busy street, you may need to set your camera at ISO 800 so as to freeze the motion of people moving quickly down the street. This means you will capture as many details as possible without blurriness.

3. Your subject

As we mentioned earlier, high ISO values can affect dynamic range, color retention, and detail recording (amount of noise). This means that a high ISO can have higher negative consequences on some people than others.

For instance, larger eyelashes or loose hair during windy conditions can create a lot of noise in an image. Therefore, it is important that you consider the importance of details and fidelity in the final output.

Final Thoughts- Which ISO Setting Should You Use?

With this knowledge on how changing ISO affects the quality of your image and the circumstances in which you should raise or lower your ISO value, you are better equipped to make decision on the right ISO value to use.

However, it is always recommended that you use the lowest ISO value (base ISO) to produce the highest quality image in ideal scenarios.

Posted in: Camera basics