How can you avoid and reduce noise in your photos?

Monday 7 February 2022, 16:32 by Huub Keulers | 18,127 views | 19 comments

This article was translated from Dutch with the help of AI. Read the original.

We have all seen it in our photos: noise that sometimes makes our photos look ugly. But how can you prevent this noise? And when it cannot be avoided, how can you reduce noise in photos?

In this article, I will briefly explain how to prevent or remove noise.

What is noise?

Noise is essentially a disturbance of light sensitivity. The disturbance shows black or coloured pixels that should not be there. Every camera has noise reduction. However, there is a distinction between two types of noise.

With colour noise, coloured pixels appear among the correct pixels. Luminance noise is a milder form, where the pixels appear in different shades of grey.

What causes noise?

Noise is introduced when you take a photo with a long exposure time or use a high ISO setting on your camera.

But what counts as a high ISO setting? That depends on your camera model, but these days most cameras start to produce noise around ISO 1600 or 3200.

Compare it to turning up the bass on your sound system. With lots of bass, the sound will distort and the sound quality will get worse.

Does this mean you should never use long shutter speeds or go above ISO 100? No, of course not. Sometimes you have to, or even want to, use long shutter speeds or increase the ISO.

Landscape photographers, event photographers, corporate photographers and sports photographers sometimes shoot in low light, which requires a long shutter speed and/or a high ISO.

At the same time, there are simple ways to prevent too much noise in your photos.

Five ways to reduce noise

Below, I share five methods for minimising noise while taking photos. Not every method applies to every situation, so it is worth knowing them all and carefully choosing the right method for your specific situation.

1. Shoot at lower ISO settings
Yes, we are starting with the most obvious method. But photographers often push their ISO too high, too quickly, which leads to poor image quality.

If your camera is three years old or newer, its high-ISO quality should be perfectly good. You should not see too much noise appearing in your images, even up to ISO 3200.

However, a lot of noise can still become visible at higher ISO values, such as ISO 6400, ISO 12800 and beyond.

So do not increase your ISO unnecessarily. Instead, consider your exposure and realise that shooting at a high ISO will produce more noise in your photos.

Increase your ISO when necessary, but consider other options before choosing, for example, ISO 12800:

• Open your aperture to the lens's widest opening, for example f/2.8;
• If you are shooting in low light, use a tripod and lengthen your shutter speed;
• If you want to take a portrait, for example, use a flash.

Each of these strategies helps you get a nice, clear exposure without unnecessarily increasing the ISO.

If your shots are still too dark, you will of course need to increase the ISO. I recommend taking some test shots to find out what your camera's ISO capabilities are and at what point the ISO settings really reduce image quality.

For years, I shot with a Canon 5D mark I and knew that anything above ISO 1,000 was really difficult to use. Noise at ISO 1,000 and above was difficult to remove. And when I did manage to remove it successfully, the entire image looked like a watercolour painting 'thanks to' the noise reduction process.

So I worked within my limitations. These days, there are much better solutions for reducing and removing noise. In the latter category, the software programme 'Topaz DeNoise Ai' is one of the best solutions.

2. Shoot in RAW format
Does the idea of shooting in RAW intimidate you? It should not. RAW is a great way to get the most out of your images, so make sure you use it.

However, you do not always have to shoot RAW. But when you notice that you have less light available, definitely switch to RAW.

Why is this so important? Jpegs come with compression, a process in which noise is 'baked into' your images. This makes removing noise on your computer afterwards very difficult.

3. Get the exposure right
Brightening an exposure that is too dark makes noise more visible. That is why it is essential to get your exposure right from the start.

When you are taking photos, I strongly recommend checking your camera's screen, including the histogram, to make sure that your exposure is correct.

And do not be afraid to take several photos with different exposures, especially when dealing with a difficult scene. Better safe than sorry!

The higher your ISO, the less forgiving your photo is. In other words, if you use a high ISO value, you had better get the exposure right, because brightening an underexposed, high-ISO photo will result in an image with lots of noise.

This is called 'Expose To The Right' (ETTR): expose towards the right-hand side of your histogram. Of course, do not overexpose either. Although overexposure will not cause noise problems, it will wipe out details in the highlights, which is never a good thing.

4. Be careful with long shutter speeds
Long shutter speeds often produce images with lots of noise. The camera sensor will heat up and cause unwanted noise. Do not let this stop you from using long shutter speeds.

You could even consider taking a series of long exposures and then checking each file for noise on your computer.

Once you have determined your camera's limitations, make sure that you do not set the shutter speed longer than your camera can handle. The main point here is to know the limits of your equipment and shoot within those limits.

5. Use in-camera noise reduction
Most cameras offer a function called long exposure noise reduction. If you shoot in jpg format and take long exposures, it is a good idea to turn this on.

Why?

Well, as discussed above, photos with a long exposure time are particularly susceptible to noise. A long exposure noise reduction option is designed to counter this problem.

Your camera then takes a second exposure and uses the noise profile of this second image to reduce noise in the first photo.

However, long exposure noise reduction has a serious drawback: it takes time, usually as long as the original exposure.

So if you use a shutter speed of 30 seconds, the camera needs an extra 30 seconds to remove the noise. And if you shoot for an hour, you need another hour to reduce the noise, which is a very long wait!

So yes, it can be impractical if you are taking 10-minute exposures. But for medium-length long exposures, it is often worth using.

Reducing noise in Lightroom or Adobe Camera Raw

Even with the best techniques, you will still get noise in your photos, at least occasionally. That is where post-processing techniques for noise reduction come in.

Below is my recommended workflow with Lightroom Classic or Adobe Camera Raw. Keep in mind that you can use similar methods in other programmes, such as the previously mentioned 'Topaz DeNoise Ai'.

100% enlargement of the man's dark coat, with lots of visible colour noise
Step 2: Adjust the Luminance slider
Under the 'Detail' tab, you will find the 'Noise Reduction' option. The 'Luminance' slider reduces luminance noise, that is, noise caused by overexposed or underexposed pixels.

A great many high-ISO images suffer from excessive luminance noise. So zoom in to 100 per cent and then increase the 'Luminance' slider until the noise starts to disappear.

Do not go too far, though.

In Lightroom, you will find the various noise reduction options under the 'Detail' tab.
Step 3: Refine your result with the 'Detail' and 'Contrast' sliders
The 'Detail' and 'Contrast' sliders control the amount of detail and contrast retained in your photos after luminance noise reduction.

You can see that noise reduction 'smooths out' noisy pixels, which automatically reduces detail and contrast. But by increasing these sliders, moving them to the right, you retain more detail and contrast.

As you would expect, however, the sliders have a drawback:
When you increase the values, you also reduce the strength of the noise reduction. So while you get a sharper image, you also see more noise again.

Step 4: Adjust the colour slider
The 'Colour' slider reduces colour noise, the second type of noise found in your photos, often in underexposed shadow areas. So increase the 'Colour' slider and zoom in to 100 per cent to see the effects.

Here you can already clearly see that the colour noise has been removed
Step 5: Refine your result with the 'Detail' and 'Smoothness' sliders
As with luminance noise reduction above, you can further adjust your photo with the 'Detail' and 'Smoothness' sliders.

Do you want more detail in your photo? Then increase the 'Detail' slider, moving it to the right. Higher values protect thin, detailed colour edges, but can also result in colour speckles. Lower values remove colour speckles, but can lead to colour bleeding.

Do you want to keep colours nice and even? Increase the 'Smoothness' slider. And you are done!

The final 100% enlargement after noise reduction

A final note on noise reduction

Although I wish I could give you standard, one-size-fits-all noise reduction settings, that is simply not how it works. Every photo is different, so you have to check each adjustment until you get the result you want.

I tend to increase 'Luminance' and 'Colour' to around 50, and then work from there. I move each option up and down and pay close attention to how it affects the photo while zoomed in to 100 per cent.

After each adjustment, I then zoom out to see what effect it has on the overall image. And when I am happy with an adjustment, I move on to the next slider. Is the process a little laborious? Certainly. But if you do it properly, you will eliminate the ugliest noise in almost every photo.

Practice is important here too, so try this on as many images as possible. Before long, you will be able to predict the effect of each change.

The final photo after editing in Lightroom

Conclusion

Now that you have read this article, you know that avoiding and reducing noise does not have to be too complicated. Just follow the steps I have given you and your images will improve.

Now it is your turn: Do you have any other tips for reducing and removing noise? Share your thoughts in the comments below.

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