What is Noise in Photography?

This is a guide covering noise in photography.

Have you ever tried to take a photovgraph at night and noticed an unwanted grainy effect ruining your picture? If yes, you have experienced the frustrating problem of noise in photography.

It is one of the most common issues photographers face who are trying to shoot in low light.

But noise is not inevitable— meaning, you can avoid it. There are ways to reduce noise in photography (though a number of photographers actually prefer the ‘Noisy’ style for some photographs), and this article will tell you everything you need to know about Noise.

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 would have lots of grain and noise in them. 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 are shooting in low light when there is 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 more in detail about signal-to-noise ratio in the upcoming sections.

The thing is it is technically impossible to produce a photograph without any noise. A small amount of noise would always be present.

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

Generally speaking, a good photo is one with as little noise as possible. These sharp images can be enlarged, manipulated, and used for different purposes without losing their integrity.

When a photograph has too much noise, smaller details will appear unclear and the image would be considered unusable for many purposes, like large-scale printing.

What Causes Noise in a Photo?

Again: 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 there is a lot of noise in your photo, it generally means that you did not capture enough light.

But noise can also be caused by other factors. Let’s discuss the three main causes, starting with the most common issue: light.

1. Too Little Light

Noise happens when you are taking photos in a dark environment, like at night.

All digital cameras have an electronic sensor — which is responsible for measuring the light in each pixel from the scene you are trying to shoot.

Interestingly, the sensor is also made up of a lot of tiny pixels. This causes the “background noise” that we were talking about earlier.

When you are taking night photos, the sensor will measure a low amount of light from each pixel.

When the light measured is too low, it becomes too close to the background noise that the sensor naturally carries, and manifests as the grainy dots we call “noise” all over your pictures.

This is why when you shoot in low light, your image will come out with a lot of noise.

2. High ISO Settings: Trying to “Fix” Little Light

In an attempt to reduce noise and compensate for low light, some photographers may opt for higher ISO settings.

But setting a higher ISO does not automatically mean noise is reduced.

In fact, it can create even more noise— a high ISO is the number one contributor to noise.

3. Slow Shutter Speed: Too Much Light

A camera’s shutter speed indicates the duration of time that the camera shutter (light sensor) opens.

When the shutter setting in your camera is not appropriate to what you are trying to shoot, the noise will inevitably appear.

If your shutter speed is too slow, your light sensor “collects” more light than it needs to, and the sensor will then measure the accumulated light in each pixel.

Since the sensor is also made up of a lot of pixels, this combination of high pixels will result in noise.

This time, noise is created from having too much light, instead of too little.

What’s An Acceptable Amount of Noise?

Since it is impossible to get rid of all the noise, most people consider photos with a minimum of 30dB signal-to-noise ratio “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.

When enlarged, a photo with too much noise will simply look blurry and distorted.

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 that you are trying to photograph an ancient artifact with intricate details for a museum publication.

In this case, detail and color fidelity are of paramount importance— 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 noise distorts light, color, details, and the overall fidelity of a photograph.

If you are trying to produce an image that represents a scene as accurately as possible, then noise is definitely bad.

A picture with too much noise will also look bad when you try to enlarge it for printing purposes. The noise, or distorted pixels, will look even more deformed.

But photography is an art, and rules bend all the time when it comes to artistic pursuits. The other, non-conventional answer to this question is then: 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 applications, like VSCO (a photography editing application with 40 million users per month), 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.

Because images with noise appear “rougher”, it is sometimes the perfect technique when trying to photograph the more “gritty” side of life, such as when taking pictures of war.

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 take control of 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: shot noise, and digital noise.

While these two types of noises are caused by entirely different problems, they may visually manifest in a similar way. Let’s discuss these two types of noises briefly.

1. Digital Noise

This type of noise is also called the “electronic noise”. It is the result of randomness caused by the internal workings/ electronics of your camera.

Noise caused by a small light sensor in your camera is also categorized as digital noise.

2. Shot Noise

Shot noise, on the other hand, is noise caused by the inconsistent number of photons of the object you are capturing. Photography is the art of capturing reflected light, and many times, these lights are random and not fixed.

Imagine a scene with a mountain, some trees, and an ocean. In this case, all three objects are reflecting different amounts of lights in an unfixed pattern.

The result of this is the shot noise. Shot noises usually will appear more strongly in your photos compared to digital noise.

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 come with 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.

Be careful to not overdo it, though, since too much noise reduction will result in a plastic-like texture.

Allow your photograph to maintain a certain low level of noise.

How Can I Reduce Noise in Photography?

Noise reduction is not a complicated process to perform on your computer if you have noisy pictures, but 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 in order 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 DSLR, 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 having 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 to not 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, well, reduce noise.

You can check out this step-by-step guide on how to reduce noise on Lightroom.

Final Remarks

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.