The lowdown on using high ISO settings in photography

Photograph of upside down trees.

We began our photography career a few years after getting married and quickly found our voice through a collaborative approach to image-making. After more than 10 years of working together, our love of photography has evolved alongside our relationship and become an integral part of our lives.

Initially guided by the portrait work of photographers such as Richard Avedon, Annie Leibovitz, and Irving Penn, we developed an affinity for working in a studio where the abundance of light from our flashes allowed us to use the lowest ISO settings possible to create images full of rich tonality and dimension.

Image credit: Shalan and Paul.

Image credit: Shalan and Paul.

More recently, we've begun to explore the world outside the studio. In these dynamic, ever-changing environments, we prefer to work quickly, capturing pictures as close to the moment of discovery as possible. To achieve this, we trade studio lighting for natural sources and leave the tripod behind. Using higher ISO settings than we typically would in our studio allows us to work unencumbered, even in the most challenging conditions, while achieving a similar degree of clarity and definition.

Understanding ISO

In digital photography, ISO is a camera setting used to control picture brightness. Combined with a camera's aperture and shutter speed, it completes a powerful toolset that enables photographers to realize their creative vision.

Overseen by the experts at the International Organization for Standardization, the eponymously named standard originated in film photography and is used to define a particular emulsion's light sensitivity. Represented numerically, the higher the ISO rating, the more sensitive the specific film is to light. Therefore, higher sensitivity film requires less light to create an adequately bright image.

ISO works similarly in digital photography. However, while it can be practical to think of it as controlling the camera sensor's light sensitivity, it's more accurate to consider it like a volume knob. Turning it up amplifies the electrical signals generated when light strikes the sensor, resulting in a brighter image.

When to use high ISO settings

High ISO is generally well suited to low-light situations, especially when a fast shutter speed or a narrow lens aperture is essential to achieving a creative goal. For example, using a higher ISO setting for hand-held street photography at night allows one to use fast shutter speeds to create bright, sharp images. By contrast, when photographing a group of people outside on a cloudy day, using a high ISO setting with a narrow aperture can result in a brilliant image with a deep depth of field that brings everyone into focus.

In conditions such as these, where the required aperture or shutter speed setting causes less light to reach the sensor, turning up the ISO is often the easiest way to maintain a bright and balanced exposure.

The trade-offs of high ISO

Working with less light heightens the impression of image noise. Noise is a type of visual distortion that appears as random specks of color or tone. While a certain amount of it is unavoidable, the higher the ISO, the more noise you will likely see in your images. In extreme cases, it can significantly detract from a picture's overall quality.

When a camera sensor converts light to electrical signals, the amount of light received determines the signal strength. Increased light levels lead to greater signal strength and a brighter result. Less light has the inverse effect.

Noise is more noticeable when signal strength is low. Because of this, it's typically more visible in darker areas of an image, such as deep shadows. Additionally, working in low-light conditions or with a restrictive aperture or shutter speed results in less overall light reaching the sensor. Increasing the ISO will produce a brighter but grainier image in this case.

Another trade-off of high ISO relates to the impact on a camera's dynamic range. Dynamic range is the ratio between the darkest and lightest brightness values a camera can reproduce without exhibiting excessive noise. Because noise is more apparent in darker areas, bumping up the ISO means those regions will become excessively noisy faster than lighter areas. Essentially shrinking the range of values the camera can cleanly capture.

Do higher ISO settings affect sharpness?

While High ISO does not directly affect sharpness, prominent noise in a photograph can impact the impression of fine details. For example, excessive noise may obscure delicate branches when photographing winter trees in low light. Fortunately, thanks to Adobe Lightroom and Adobe Photoshop’s new Denoise feature, you are able to minimize noise while maintaining fine image detail.

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Using a high ISO may create unwanted noise that can obscure fine details. Image credit Katrin Eismann.

Getting to know your camera

Some cameras can be pushed far further than others before image noise becomes objectionable. However, deciding how much noise is too much is subjective. Some photographers seek to always minimize it, leading them to work exclusively with relatively low ISO settings. Others freely embrace a more expansive ISO range and use the textural quality of noise to imbue a sense of energy and spontaneity in their work. With this understanding, defining the ideal ISO range that achieves acceptable results across various shooting conditions with a given camera is vital.

First, find one or more scenes to photograph that match the conditions typically encountered. Shoot a sequence of pictures in each setting, gradually increasing the ISO from the lowest setting possible to the highest. Use an aperture or shutter priority mode if available, or manually balance the exposure to make it easier to evaluate the results. Additionally, a tripod can ensure a matching composition making shot-to-shot comparisons more straightforward.

Next, bring the images into Lightroom and compare the results. Step through the sequences and examine each picture, noting when you feel image noise appears too intense or distracting. It can also be helpful to zoom in to 100 percent to evaluate the impact of noise on fine detail. With an established upper limit, you can be confident that ISO settings within your ideal range won't negatively impact image quality. Some cameras even allow you to set a maximum ISO limit, ensuring your preferred level isn't exceeded when working with auto exposure.

ISO and post-processing

Circumstances sometimes compel photographers to work outside their preferred ISO range. For times like this, Lightroom (and Adobe Camera Raw) offers an easy-to-use set of noise-reduction tools to help deal with excessive noise.

Denoise in Lightroom and Adobe Camera Raw

The Denoise feature uses powerful artificial intelligence to automatically remove noise from photos without losing any detail. It can be used on any images but is especially useful for high ISO, low light photos. Make sure to try it out on older camera files that suffer from noise due to high ISO or low light scenarios. Please note: Applying Denoise will create a separate DNG file that you can continue to edit in Lightroom and Photoshop.

Applying Denoise in Adobe Lightroom.

Applying Denoise in Adobe Lightroom. Image credit Katrin Eismann.

Manually reducing noise

There are two types of noise to watch out for; luminance and color. Luminance noise appears as monochromatic grainy specks, while color noise, as the name implies, is more colorful in appearance. Lightroom provides separate controls to deal with both.

To reduce image noise in Lightroom, try the following:

  1. Zoom in to 100 percent to better evaluate the noise present.
  2. Determine what type of noise needs to be addressed; luminance, color, or both.
  3. Under the Detail panel, tap to expand the Manual Noise Reduction tools and move the applicable slider(s) to the right to reduce noise.

While you can use the Denoise tool that uses AI to automatically remove noise from your image, you can still make manual adjustments if you prefer. Expand the Manual Noise Reduction tools to reveal the Noise Reduction and Color Noise Reduction controls. These sliders can be used to fine-tune the adjustment and restore fine detail. Remember, the key to successful noise reduction lies in its name; reduce, not remove. Overly aggressive edits generally lead to blurry-looking images lacking refinement.

Before (left) and after (right) using Denoise in Lightroom. Image credit Pei Ketron.

Before (left) and after (right) using Denoise in Lightroom. Image credit Pei Ketron.

Another critical consideration is reproduction size. When an image is reduced in size, as it would be on the web or social media, the impact of even elevated noise levels becomes less apparent. In these cases, refined noise reduction may be unnecessary. However, as reproduction sizes increase, such as when producing a large print, these adjustments become much more consequential.

Photos of S

The swans on the left are part of the original image. On the right, you can see the effect of using Denoise for noise reduction. Image credit Katrin Eismann.

High ISO, noise reduction, and shooting RAW

When shooting in non-Raw formats, such as JPEG, in-camera noise reduction is effectively baked into the resulting image. Additionally, some cameras apply overly aggressive noise reduction by default, causing unnaturally smooth or blurry-looking results. These types of artifacts typically can't be fixed in post-processing.

Shooting in a Raw format bypasses in-camera processing allowing one to leverage Lightroom's powerful noise-targeting adjustments to retain the highest possible quality.

A world of possibilities

As cameras and software rapidly evolve, visual creators must continuously aspire to learn and innovate. While the trade-offs of high ISO can be deal-breakers for some, the benefits outweigh the concessions for others, empowering them to create compellingly luminous photographs in even the most challenging, low-light conditions. Working with high ISO settings today opens a world of possibilities photographers could only dream of just a few years ago.