Basics for Beginners: What is ISO in Photography?

Basics for Beginners: What is ISO in Photography?

In the world of photography, there are several technical terms that can be overwhelming for beginners. ISO is one such term that often confuses aspiring photographers. In this article, we will try to simplify the concept of ISO and explain its significance in digital photography.

photo by ShareGrid on Unsplash

What is ISO?

ISO stands for International Organization for Standardization and sets standards for various industries, including photography. In photography, ISO refers to the sensitivity of a digital camera’s image sensor to light. It measures how much light is needed to create a well-exposed image. In simpler terms, ISO determines the camera’s ability to take pictures in low light without compromising quality.

In the days of film, ISO referred to film sensitivity. It still worked much the same way today’s modern cameras do, in that ISO 100 was great for bright sunny days, while ISO 1600 or even ISO 6400 was more for dark indoors or nighttime photography.

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photo by Caleb Woods on Unsplash

Understand ISO settings

ISO is represented by a numerical value, such as ISO 100, ISO 400, or ISO 640. The lower the ISO number, the less sensitive the image sensor is to light, resulting in less noise in the image. On the other hand, higher ISOs increase the sensitivity of the sensor, allowing you to shoot in low-light environments, but at the cost of more noise.

Photo by Ernest Karchmit on Unsplash
photo by Ernest Karmit on Unsplash

What is Noise?

What exactly is sound? Noise in photography refers to the grainy veil that can obscure details and degrade the quality of an image. It occurs in low-light situations or when using high ISO settings, as the camera’s sensor struggles to capture enough light, resulting in amplified noise. Noise can distort colors, reduce sharpness, and create an overall lack of clarity. Often renders the images unusable. Noise can also be caused by severely underexposed images instead of a high ISO.

What is BASE ISO?

Many camera manufacturers have standard ISO settings, which is the lowest native ISO on that camera (or brand). Why is this important? It gives you the ability to produce the highest image quality, minimizing the visibility of noise as much as possible. Older DSLRs and some modern cameras have a base ISO of 200, while most modern digital cameras (like my Sonya7RIII) have a base ISO of 100. Google the base ISO for your camera and always try to keep the base ISO for the highest image quality. However, that is not always possible, especially in low light conditions.

ISO200 - Minimal noise, even in low light
ISO200 — Minimal noise, even in low light

ISO and exposure

ISO is closely related to two other fundamental aspects of photography: aperture and shutter speed. Together, these three factors determine the exposure of an image. While aperture controls the amount of light entering the camera through the lens, and shutter speed controls the duration of the exposure, ISO affects the camera’s sensitivity to light. Balancing these settings is essential to get a well-exposed image without overexposure or underexposure.

Which ISO should you use?

The choice of ISO setting depends on the shooting conditions and the desired artistic effect. For well-lit environments, such as outdoor daylight, a low ISO setting (such as ISO 100 or 200) is appropriate. This ensures minimum noise and maximum image quality. In low light situations such as indoor or night photography, higher ISO values ​​(e.g. ISO 800 or higher) can be used to capture brighter images. However, it’s important to note that higher ISOs can introduce noise, decreasing overall image quality.

Modern digital cameras and ISO performance

Advances in camera technology have significantly improved the performance of higher ISO settings. Many modern cameras can handle high ISOs with minimal noise, enabling photographers to capture quality images even in difficult lighting conditions. However, it is still advisable to use the lowest possible ISO setting to maintain optimum image quality where possible.

Topaz labs with a high setting (93) using the Low Light model.
Topaz labs with a high setting (93) using the Low Light model.

Can you remove noise in post production?

Of course, it’s not always possible to use ISO100, especially in low-light situations or when you need to increase your ISO to get a faster shutter speed. That’s where post production can help. It can’t always fix every image, but it can help immensely in certain situations. you can try Lightroom Denoise, Topaz Denoise, Luminar Neo Noiseless AIDXO Pure Raw3, to start with.

A final word on ISO

ISO is a crucial setting in photography that determines the sensitivity of the camera’s image sensor to light. Understanding ISO and its relationship to aperture and shutter speed helps photographers capture well-exposed images in a variety of lighting situations, balancing sensitivity and image quality.

Knowing more? Check out these Photofocus articles:

  • ISO made easy: Understand your ISO settings
  • Why does my ISO 100 image contain noise?
  • Photography 101: Using Auto ISO