Noise

Noise in photography, often showing up as grainy or speckled artifacts, can be seen as the shadowy counterpart to low light and high ISO, challenging us photographers to find harmony between illumination and clarity...

What is noise in photography?

In simple terms, noise is a type of visual distortion that affects how pixels look in a digital photograph. It can happen regardless of the type of camera you are using— from mid-range smartphones to expensive DSLRs.

Usually, noise makes your photograph appear grainy instead of flat and sharp. Think of an old photograph taken with a film camera. Usually, these older photos have lots of grain and noise. In the worst cases, noise can really ruin a good picture by adding splotches of discoloration.

Noise is what happens to your photos when you shoot in low light with a low signal-to-noise ratio. This ratio is measured in decibels, and the standard for professional photos is a minimum of a 30dB signal-to-noise ratio.

However, some photographers have different standards when it comes to noise, and what may be “too noisy” to a photographer may be perfectly fine to others. We will be discussing the signal-to-noise ratio in more detail in the upcoming sections.

So, the key is not to eliminate all the noise but to try to reduce the noise as much as you can so that the image becomes usable.

Generally speaking, a good photo has as little noise as possible. Sharp images can be enlarged, manipulated, and used for different purposes without losing their integrity. When a photograph has too much noise, smaller details appear unclear, and the image is considered unusable for many purposes, like large-scale printing.

What causes noise in a photo?

All pictures, no matter how crisp, technically have some noise in them. Noise is like the “background” of all pictures, and the only way to minimize noise is by overpowering it with the scene you are trying to capture by photographing more light.

When a photo has a lot of noise, it generally means that you did not capture enough light. However, noise can also be caused by other factors. Let’s discuss the three main causes, starting with the most common issue: light and high ISO values.

High ISO settings: Trying to “fix” little light

In an attempt to compensate for low light, photographers may increase their camera's ISO settings, enhancing the sensor's sensitivity to light. However, a higher ISO also amplifies noise, making it more visible in the final image.

This electronic noise becomes particularly noticeable in low-light environments, such as night scenes, where the camera's sensor struggles to distinguish between the actual light signal and the inherent electronic noise, resulting in images that appear grainy. Thus, while a higher ISO can make it easier to capture images in the dark by brightening them, it simultaneously increases the visibility of noise.

What's an acceptable amount of noise?

Since it is impossible to eliminate all noise, most people consider photos with a minimum signal-to-noise ratio of 30 dB “acceptable." But, then again, there is no cookie-cutter definition of an acceptable noise amount. It really depends on what you are trying to achieve as a photographer.

If you want to use your photograph for commercial or exhibition purposes, for example, you might want to aim for as little noise as possible.

In some special situations, having a higher-than-usual noise is also accepted professionally, like when sports journalists are trying to capture a match at nighttime. In this case, there is nothing really the photographer can do (capturing high-speed action in low light is very difficult), so some amount of noise is acceptable.

But let’s say you are trying to photograph an ancient artifact with intricate details for a museum publication. In this case, detail and color fidelity are paramount— if your photograph has too much noise, it is simply unusable.

When in doubt, try to imagine how your image would look after it is printed. How big do you want your print to be? How would your photo “react” when enlarged/ shrunk to the dimensions? Would it be too noisy, or would it maintain its integrity? Use your gut feelings.

Is photo noise bad?

The conventional answer is: Yes, photo noise is bad.

Photo noise is bad because it distorts light, color, details, and a photograph's overall fidelity. If you are trying to produce an image that represents a scene as accurately as possible, then noise is definitely bad.

However, photography is an art, and rules always bend when it comes to artistic pursuits. The other non-conventional answer to this question is: No, noise is not always bad.

When noise is good?

Some photographers actually prefer noise in some of their photographs. Just take a look at some of the most popular editing applications on your smartphone.

Some photography editing applications actually allow you to add noise, or grain, to a perfectly sharp photograph. Why would anyone want noise in a perfectly fine photograph?

Well, for one, having noise in your photograph can actually add character and mood, depending on what you are trying to shoot. Usually, this mood is nostalgic or vintage, reminiscent of old film photos.

Having noise or an extra layer of somewhat uncomfortable texture evokes emotions in the human eye and mind that a “smooth” picture cannot.

Noise can also be good for taking very realistic portraits. This is almost the opposite of smoothing over the skin using Photoshop— instead of trying to hide imperfections, noise will amplify those textures. Noise is the distortion of pixels. It is “bad,” but if you can control the distortion and play around with it, noise can actually add depth to your photo.

Types of noise in photography

Generally speaking, there are two main categories of noise in photography: luminance noise and color noise.

While entirely different problems cause these two types of noises, they may visually manifest similarly. Let’s discuss these two types of noises briefly.

1. Luminance noise

Luminance noise affects the lightness or darkness of your pixels. This type of noise is most similar to film grain and can sometimes be aesthetically acceptable, adding a kind of vintage texture.

2. Color noise

Color noise is often seen as random color specks like splotches of red, green, or blue. This type of noise is problematic and can be more distracting and harder to correct.

What is noise reduction in photography?

As the name suggests, noise reduction is the process of reducing the appearance of noise in photographs. Some cameras are manufactured with built-in noise reduction features, while other cameras would require extra work to reduce noise.

If your camera does not have a built-in noise reduction feature, you can quite easily edit the photos afterward using popular photo editing programs to reduce noise. The ‘luminance’ slider in Lightroom’s Develop Module allows you to reduce noise as much as you would like. Drag the slider to the right to reduce noise.

How to reduce noise in photography?

Noise reduction is not a complicated process to perform on your computer if you have noisy pictures. Still, if you can practice shooting with less noise, this skill will definitely take you further as a photographer.

There are a few things that you can do to reduce noise. Use this list as a non-exhaustive general guideline or indicator for experimenting with different settings. You may have to practice a few times before getting comfortable with these settings.

1. Experiment with lower ISO

Since one of the main causes of noise in photos is high ISO, it is only logical to experiment with lower ISO settings. Try to shoot at the lowest ISO possible. Depending on the size of the camera’s light sensor, some DSLRs are able to capture at higher ISO without risking noise in the picture.

But if you are unsure about your camera, you can try shooting with a wide aperture setting or use a tripod in low light— this way, you do not have to increase your ISO and risk making noise in your photos.

2. Experiment with higher exposure

Another way to reduce noise while taking photos is by experimenting with higher exposure settings (such as aperture (f-stops) and shutter speed) instead of increasing ISO for brightness.

Unlike ISO settings, increasing exposure on your camera will not increase noise. Be careful not to overexpose, though. While it will not cause noise, smaller details in your photo might be lost in the light.

3. Using Adobe Lightroom

It is not difficult to reduce noise in post-production if you are using the correct programs. Adobe Lightroom, one of the most popular editing programs for professional photographers, has a noise reduction slider that you can use to reduce noise well.

In conclusion, noise is a visual distortion of pixels that often appears in photographs when a picture is taken with insufficient light. Noise is generally not very good in photos, though some photographers use it intentionally to achieve emotional effects. To reduce noise, photographers can either experiment with their camera settings or edit it afterward using editing applications.