Image noise is a problem every photographer has to deal with. Those tiny dots of color or grain can spoil even the most perfectly composed image, and sometimes it seems unavoidable.
So what can you do?
Whether you want to fix it in-camera, or are happy to dive into Lightroom or Photoshop, there are several things you can do to eliminate noise. And that will help you take sharper photos.
Read on for a noise-free future.
1. Shoot at Low ISO
Noise is most commonly introduced into a photo when the camera sensor’s sensitivity is pushed beyond a level its capable of handling. This happens when you shoot at a high ISO setting.
ISO determines how sensitive the sensor is to light. It’s used as part of the so-called “exposure triangle”—along with shutter speed and aperture—that enables you to control the exposure of a photograph.
It’s shown as an ISO value, such as ISO 100, and each time that value doubles the sensitivity also doubles. So, a camera will draw in four times as much light at ISO 1600 as it does at ISO 100.
Modern DSLR and mirrorless cameras can shoot with relatively little noise at up to ISO 1600, but get progressively worse above that point. Small sensor cameras and smartphones might start to show noise at ISO 400 and beyond.
To shoot sharp photos, always keep the ISO setting as low as possible. This is easy in good light, while in low light set a slower shutter speed and select a larger aperture first. Only start bumping the ISO to a level beyond what your camera is comfortable with as a last resort.
Also, if you’re shooting in Auto ISO mode, keep an eye on what setting your camera chooses. Many cameras allow you to set a maximum ISO even in Auto mode, so make use of this too.
2. Use Faster Lenses
As we mentioned, setting your lens to shoot at a larger aperture is a good way of keeping the ISO low.
The aperture is the hole at the back of the lens that controls how much light is able to hit the sensor. A larger aperture, indicated by a smaller f-number, increases the amount of light.
Every lens is restricted in the maximum aperture it offers, so switching to one with a larger maximum (often referred to as a faster lens) can be hugely beneficial. For instance, a prime lens with an f/1.8 aperture lets in twice as much light as a zoom does at f/3.5. That’s the equivalent of switching from a potentially noisy ISO 1600 to a clean and crisp ISO 400.
3. In-Camera Noise Reduction
All camera software offers in-camera noise reduction. This is applied when you’re shooting in JPEG mode, but never in RAW. Logic states that you should turn this on and set it to the maximum level to get noise free images.
In-camera noise reduction can be a rather blunt instrument. It works by smoothing the image to blend in the noise. But it can also end up smoothing out fine details, or giving skin a fake, waxy looking texture.
Experiment with your camera’s settings to find the level you’re happy with. As a general rule, if you post-process your images in Lightroom then keep it set low. Lightroom can handle noise reduction far better. But if you upload your photos directly to Instagram or elsewhere you can afford to set it a little higher.
4. Long Exposure Noise Reduction
Long exposure photos are highly susceptible to noise because the sensor can get very warm while they’re being shot. This causes hot pixels in the image.
Cameras that can shoot with long exposures, especially DSLR and mirrorless cameras, have a long exposure noise reduction option to fix this. What’s different about it is that it usually works when you’re shooting in RAW, too.
Long exposure noise reduction works by shooting two frames. The first is your intended shot; the second is a “dark frame” shot as if you’d left the lens cap on. The dark frame captures nothing but the hot pixels, which the software then uses as a map to remove them from the original image.
5. Master Noise Reduction in Lightroom
If you’ve tried to minimize noise while shooting but are still left with some to clean up, where do you go next?
Lightroom. It’s how many professionals gets their photos to look tack-sharp.
The photo editor’s noise reduction tools are simple yet powerful. Similar tools are also available in most other image apps, including Apple Photos, and work in the same way.
There are two types of noise, and they’re tackled in different ways.
Remove Color Noise
Color noise is seen as specs of random color dotted throughout the image. It’s ugly, and you’ll always want to remove it. Fortunately, it’s a trivial fix, and you might not even need to do anything.
You remove color noise by desaturating those random dots. Lightroom automatically applies a setting of 25 on the Color Noise slider to every RAW image, and more often than not that’s enough.
You can increase it if you need to, but don’t go too far or you might start smudging the other colors. On the whole, color noise reduction shouldn’t degrade your image quality in any noticeable way.
Remove Luminance Noise
Luminance noise is random pixels that are brighter or darker than they should be, while still of the right color. Not all luminance noise is bad, as it can sometimes take on the appearance of film grain, giving your image a nice texture. It’s harder to fix fully, though.
Lightroom removes luminance noise by softening the image. This has the effect of removing fine detail, and if you push it too far natural textures will start to look artificial.
Ultimately, it’s about finding the balance between reducing noise and retaining detail. We’d always recommend prioritizing the latter.
To get started, zoom fully into your image. Then get to work on the three noise reduction sliders:
- Luminance: This is the main tool. Drag it to the point where you find a good balance between noise and detail.
- Detail: This allows you to recover some fine detail, but the effect is very subtle. It’s set to 50 by default. Increase it to add more detail, but beware of introducing unwanted artifacts to the image.
- Contrast: This slider lets you recover some of the local contrast that may been smoothed away by the Luminance slider. A value of around 10-20 often works well.
You can also apply local noise reduction using tools like the Adjustment Brush or Graduated Filter. You get less control on the settings, though, and it only works with Luminance noise.
Once you’re done you’ll probably need to sharpen the photo. This can increase the noise once more. Again, you have to find a balance between the two that you’re happy with.
6. Discover Exposure Stacking in Photoshop
When you’re shooting low light photos on a tripod you can minimize noise by shooting at slower shutter speeds. But you won’t be able to get rid of it entirely.
Photoshop, and other major photo editing apps like Affinity Photo, have an ingenious fix that solves the problem automatically.
It’s called exposure stacking, and it works by blending multiple images that are essentially identical. If they’re shot together, from a tripod, the only differences will be the dots of noise that are distributed randomly on each frame.
The software identifies those differences as noise, and discards them.
The process for Photoshop goes like this:
- Shoot between three and six images (without moving the camera in between).
- Open Photoshop and go to File & Scripts > Open Files into Stack.
- In the Load Layers box that opens, check the options labelled Attempt to Automatically Align Source Images and Create Smart Objects After Loading Layersthen hit OK.
- Go to Layer & Smart Objects & Stack Mode & Median.
That should be it.
A similar process is used in smartphone camera apps that have an HDR mode. They shoot multiple frames in succession and combine them. It’s primarily designed to maximize the dynamic range of the camera, but also serves to reduce noise and help you take sharper photos on your phone.
7. Be Careful When Post-Processing
Image noise is the result of the physical limitations of your camera’s hardware. But it can also be created and exacerbated by poor post-processing of your photos.
Lightening up an image, excessive color correction, and over-sharpening can all seriously downgrade the quality of a photo.
If you want to process your shots, then you should always try to shoot in RAW. RAW files can handle a lot more editing work than JPEGs. You can even shoot them on iPhones and Androids these days, so there’s no excuse.