Photography 101: Noise Control

Is noise making your photographs better or worse?

Noise can be a tricky aspect of photography, and there are still many photographers who have a difficult time understanding the different factors that make a photograph noisy. For the best picture quality, the composition has to be perfect. This requires proper camera settings based on the subject and available lighting.

It took me minutes to learn to use a DSLR the first time I bought one. But it took months for me to master the art of DSLR settings. You barely learn anything from auto-modes. The art is in altering the ISO, aperture, and shutter speed, and taking a picture manually. Noise is the outcome of a particular setting. And for a long period, I thought that taking noisy pictures with high ISO settings made my captures better. I couldn’t be more wrong!

Understanding what Noise is

This photo, taken at ISO 12,800, has a tremendous amount of noise. This is way too much for any reasonable use.

Noise is grains in a picture. It ruins the integrity of the color composition, veils the entire image with dots, and blurs out details. Could it be any worse?

You can make a picture come out noisier, or less, by fluctuating ISO settings. When I first tried this, I swear my shutter sound became louder. But that doesn’t affect the quality of the picture being taken, so it’s a topic better left undiscussed.

Later on, I figured that high ISO settings can make images noisy and ruin the overall composition. There will always be some amount of noise in every picture. If you record your voice on your phone, you will notice that there is a sound in the background that couldn’t be heard during the recording. This sound is “noise” in a video.

Similarly, when a camera snaps a photo, a lot of unwanted light is recorded and makes it noisy. If you decide to keep the cap on your lens and take a picture, it is more likely that it will come out with bright pixels if the brightness of the picture is increased in an editing software. These pixels are noise.

So, why does it happen?

As mentioned earlier, every photo has noise to some degree. It is impossible to edit this or prevent it from happening, because it’s an inherent property of light. There are two types of noise in photographs- Shot Noise and Digital Noise. In both cases, the picture will have dark/bright/discolored pixels, and both can make a picture unusable.

Shot/Photon Noise

The reason why we can see in general is because light is being reflected from every surface around us. This light is captured by our eyes, and our brain paints the picture. The same is true for a camera. Shot noise happens because of the photons reflecting from the subject being photographed. The photon number being emitted from the subject varies with every second of exposure and gives the picture a graininess. The effect is inconspicuous and random.

Consider a light bulb. The average photon emission of a dim light is around 1,000 photons. But this number isn’t a constant. In the first second of exposure, let’s assume that the bulb is emitting 1,000 photons. In the following second, it can be 986 photons, 1,024 photons after that, and so on. For every one second long exposure, the pictures will come out differently because of this inconsistency. This is called Shot Noise.

Digital Noise

Digital noise happens because of imperfections in your camera. Usually, the internal hardware or the lens is to blame for this. The effects of digital noise are comparatively more distinct than shot noise. The reason why enhancing a black image (if taken with your lens cap on) can show grains is because of digital noise from your setup. This can be easily countered by upgrading your gears for better performance.

How I reduce noise from my photography

There will always be noise in a photograph, and you can never take it completely out of a picture. The noise is an inevitable backdrop that has to be dealt with by allowing more light to enter through your lens. By doing that, you are capturing as much light from your subject/focal-points as you can to overpower the grains in the background and capture more details.

If you have taken a picture without capturing enough light emitting from the subject, the picture will be dark- that’s a given! Furthermore, when you decide to do a little bit of post-production to brighten the image, it will become grainy and lose color. Essentially, you are making the noise more visible.

Signal-to-Noise ratio

The term signal here means the actual focal point of your image and the details you want to emphasize. The overall light captured to do this is termed as “Signal.” When you’re taking a picture, noise is always in the backdrop. Photographers have to work their way through this to balance the ratio between the two.

The ratio between the signal and noise has to be inclined towards the signal, which means that the light coming from the signal has to be proportionally greater than the noisy light.

Here’s how you can reduce noise from your photographs:

  • Use longer shutter speeds so more light enters through your lens
  • Use a wider aperture to allow more light to enter at a time
  • Get more luminous exposure by photographing bright subjects

Note: Anyone advising you to lower ISO settings to reduce noise is making it simpler than it is. Lowering ISO with the rest of the settings kept the same will only make your images darker. Eventually, you will end up with a dark picture that would need post-processing. Consequentially, it will make the image noisier.

ISO adjustments can reduce noise

There’s a reason I used ISO 3200 here rather than brightening a low-ISO photo in Lightroom or Photoshop: The image quality is better, thanks to the lower level of electronic noise.

Apart from the shutter speed and aperture, ISO settings can be altered to make an image darker or brighter. It also means that you can moderate the extent of noise captured in your photographs. ISO settings cannot be used to regulate shot noise. Since shot noise is emitted naturally from the signal and is not affected by your camera settings, there is no possible way for you to reduce it by changing the ISO.

The only type of noise affected by ISO settings is digital or electronic noise. A camera with normal settings will have a reduced degree of digital noise if the ISO is increased. Again, what matters here is not the noise, but the ratio between noise and signal.

To have a good signal-noise ratio, you cannot shoot a dim scene with high ISO settings. This move will make your image brighter and reduce noise to some extent even though the subject itself is not bright. But the quality of the image will be compromised. Bright subjects always make for better photos.

If your camera can take pictures with less digital noise at higher ISO settings, that’s a good thing! But in the end, it comes down to the ratio to make a photo good enough straight out of the camera with little to no post-processing. The trick here is to flood the image with light to drown the noise in the backdrop.

My take on noise reduction software

If you’re wondering whether an editing software can take care of noise in your photographs, the answer is yes it can, but it has its drawbacks. Software will use algorithms to identify noise and reduce it. But in the process, it will reduce the sharpness of the image and harm the details in the picture. Too much noise reduction, and your image will look bland and fake.

Noise reduction software:

  • Lightroom: Fast and simple to use. Can reduce noise from raw images. The details section has different noise reduction sliders that can be used to take out luminance and chromatic noise.
  • Photoshop: You can use masks to choose where you want to reduce the noise from. It is by far the best and the most accurate software for post-processing. Photoshop uses a similar algorithm as its competitor, Lightroom, to reduce stacking and blending noise from photographs.
  • Capture One: You can reduce hot pixels from an image using this software. It will also allow you to reduce luminance and chromatic noise.
  • Noise Ninja: You can get the photo-ninja package to use this software. Undoubtedly, a top pick for the job. You can also add the plugin to Lightroom and Photoshop.
  • Neat Image Pro: This is a plugin that can be used to edit out noise by allowing the software to automatically detect heavy-noise areas and fix it. The only drawback of the software is the reduced sharpness in the aftermath.
  • Noiseware: The developer Imagenomic developed this plugin to help reduce noise from images efficiently. The interface is easy and it’s a one-click noise reduction software.
  • Topaz Denoise AI: This software automatically recognizes noise in a photograph and edits it out. It has sliders and settings that can identify noise and preserve details of the image. The “Denoise” filter can be used to target chromatic and luminance noise.
  • Skylum Luminar: It is similar to Lightroom and has multiple options to reduce noise.
  • Nik Dfine 2: A feature in the Nik collection Pro, allows users to reduce noise without the hassle of having a complicated panel. Google provides a Nik collection package for free. The software gained immense popularity ever since.

For luminance noise reduction, Topaz and Luminar can be effective. But if you want to conserve the details of your image, I’d recommend using Noiseware.

Noise reduction can be useful if you do it moderately and only to the background, not the main subject-points. You can use selective noise reduction to improve areas in your picture that represent the background and none of the details. While the obvious noisiness has to be removed, if your picture requires more noise reduction, it’s probably a better idea to reshoot the whole thing with more light.

I used noise reduction here, including local adjustments to improve the quality of the background. This is especially noticeable at larger print sizes.

Summing it all up

A longer shutter speed, a wide aperture, and more light from the source can drastically improve the quality of your photograph. While noise reduction software is always there to do the dirty work, it’s better to click an image that is good to go as soon as you import it to the computer.

Make sure to capture as much light as possible to submerge the noise in the lights from the details. You can always increase the ISO setting to take brighter images with less digital noise and do further editing to reduce shot noise.

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