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What is ISO in photography?

By KateBackdrop | 9 November 2021

A picture is worth a thousand words. However, you could argue the story your picture tells is dependent on how effective your photography skills are.

The better your capturing skills, the more complete and well-rounded the story. And while anyone can take a photo, it takes time, practice, and patience to pull off the perfect picture.

reading the light

One critical skill every photographer needs to perfect is capturing your photo in the perfect light. To achieve this, you’ll need to adjust the brightness to illuminate or darken the object or background.

Three main factors determine how bright or dark your image is. These are the ISO, aperture, and shutter speed. Today, let’s delve into what ISO is, how it affects your photos, and how to control and master it.

Image: Getty

What is ISO in photography?

As mentioned above, ISO is one of the factors that determines the brightness or dullness of your photo. In essence, ISO controls the amount of light penetrating your camera’s lens. This can then impact the dark and light qualities in your image.

Initially, the International Organization for Standardization was responsible for setting the ISO numbers used in portrait photography.

Today, while most digital cameras still follow this numbering format, the photographer has more control over their ISO settings. You can adjust the settings to match different backgrounds and photography backdrops.

For instance, the ISO you use in a studio could differ widely from what you use outdoors. By mastering ISO photography principles, you’ll have greater control over your subject and the environment.

How does ISO affect your photos?

Any amateur photographer will tell you ISO increases and decreases your photo’s brightness. However, it also affects the noise or grain levels and the dynamic range. Your photos will likely have the highest dynamic range and the lowest amount of grain at the lowest setting.

Consequently, this gives the photographer more flexibility in image post-processing. As you increase the ISO setting on your camera, the dynamic range decreases, and the grain or noise level increases.

Image: Getty
Image: Getty

What is the best ISO range to shoot with?

As with any other photography aspect, there’s no one solution for all situations. Fortunately, there are several guiding rules to finding the best ISO sensitivity level for your environment. Here’s a quick breakdown of the best ISO settings for different situations and environments;

ISO 100: This is the ideal choice when shooting outdoors on bright or sunny days. Since the natural lighting will provide bright reflections on the image, you don’t need a high ISO.

ISO 400: This ISO setting is best used when there’s ideal but less intense lighting. For example, you can use this ISO when shooting outdoors on a cloudy day or indoors near a window. Depending on the environment and light exposure, you may have to opt for a higher ISO level.

ISO 800: Since this range is mid-to-high level, it’s most ideal for indoor shots where you don’t have the assistance of a flash or other augmentative lights.

ISO 1600 and above: If you’re shooting indoors under dim lighting or when it’s dark outdoors, you’ll require a high ISO. Additionally, if there’s movement involved in the photo, you should pair the high ISO with a fast shutter speed to improve your image quality.

Pro tip: As you’re starting, set your camera to auto ISO and study how the camera differentiates environments and lighting situations to determine the correct ISO. However, you can’t always rely on auto ISO, so use it to learn and develop your style.

How do you control ISO?

Depending on the type, make, and model of your camera, the ISO settings could be in a number of places. However, locating your ISO shouldn’t be that difficult, and if you face a challenge finding it, you can always refer to the camera’s user manual. That said, here are the most common ways to find and control ISO settings on most cameras.

1. If you have a standard DSLR or mirrorless camera, you’ll need to open the quick menu settings and find the ISO section. Select your preferred value and start shooting.

2. Most high-end cameras have a dedicated ISO button on the camera. Press the button and spin the wheel to the desired setting and start shooting.

Ultimately, ISO plays an important role in the quality of your photographs. Mastering ISO usage will give you more control and improve the quality of your photos. Remember to be patient, keep exercising, and continually learn to improve your skills.

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