‘Digital Noise’ –What Is It and How To Avoid It – AHHG! Another thing I hate! Bob Wild
How to handle digital noise
‘Digital Noise’ –What Is It and How To Avoid It – AHHG! Another thing I hate!
We will always end up with poor quality photos if you don’t understand how to get rid of the things that adversely affect digital photography like digital noise.
We’ve all seen it in our photographs, that uneven grainy look which makes them appear a little unappealing. In the days when photographers used film, they referred to noise as grain, and it looked better, but the digital equivalence of noise can usually make a good picture awful. Side note here, some of us still like that grainy noisy look especially in our black and whites.
Today, we are going to look at this key photography problem in detail. As I mentioned earlier, it has affected our photography in the past and therefore, we should know how to avoid it in the future.
What Is Noise?
Noise refers to aberrant pixels. It means pixels that aren’t representing the exposure or the color of the scene correctly.
When Does Digital Noise Occur?
Noise affects your image when you shoot at a higher ISO (1600 ISO or higher on average) or shoot a long exposure image. Does it mean you shouldn’t do long exposures or never go beyond ISO 100? No, there are times when you may require, or even want to shoot in those situations. – PS I love both of these techniques and HDR is another noise gathering technique.
We landscape photographers take our shots in less light anyways. The essential things to know are how to stop excessive noise and, how to handle it in your post-production. Let us look at how you can get less noise in camera first.
1. Reduce Noise In-Camera:
Shoot In RAW Format
I know you may find difficult to shoot in RAW, but you should. RAW is a perfect way to get the most out of your photos, so ensure to use it. You do not need to shoot RAW, but you should, I can’t stress this enough shoot in RAW
The reason behind this approach is that JPEG images are compressed in camera. Therefore, if there’s noise, compressing the photo into a JPEG file will amplified it, make it more prominent. Noise in JPEG files is often referred to as ‘artifacts’. If you’re shooting at a high ISO saving as JPEG’s, the noise can become worse. Besides, in post-production, you’ve much more flexibility increasing exposure and removing noise, with a RAW file than a JPEG.
Use In-Camera Noise Reduction
In many cameras, there’ll be a function known as Long Exposure Noise Reduction or High ISO Noise Reduction. It is a brilliant idea to turn this on if you’re doing long exposures or shooting at a high ISO. In my opinion, I know someone will gasp for air after reading this. 🙂
The reason is that after you have taken the shot, the camera will analyze the picture and look for any stray pixels rendered incorrectly. It’ll then fix the pixels. However, this takes some time, often as long as the exposure period.
So let say your shot took thirty seconds, the camera will perform the analysis and corrections which will take up to another thirty seconds. It may become unfeasible if you’re doing ten-minute exposures, or multiple exposure for let’s say star-scapes, but it may be worth using this on short exposures. If you have the time, I would do it on very long exposures, as it can boost the quality of the image. Another trick for long exposures, if you do not want to wait the extra time, would be to do an extra exposure keeping the ISO and exposure settings the same, but this time with the lens cap on, then when you are post-processing you can add the cap-on exposure into the stack, and using a blend mode you should be able to remove the excess noise. Why shoot with the lens cap on? So you get the same hot pixels which can be removed later in post.
Shoot At Lower ISO Settings
If your digital camera is a higher end camera or fairly new (less than three years old), the ISO functionality should be excellent. You should not see excessive noise creeping into your shots, even up to ISO 1000. But, there might still be a little bit of noise at higher ISO numbers, so be wary of your exposure.
Shooting at a low ISO means you’ll have less digital noise in your shot. Higher ISO settings tell the sensor of your camera to group all pixels together to receive more light. The grouping effect can make your picture look noisy and gritty.
How do you stop shooting at a higher ISO? You need to open your aperture to its widest setting if possible i.e. f/2.8. If you’re shooting in low light, you could use a flash, or use a tripod if possible.
If none of these choices offer you the right exposure, then you’ll have to push the ISO. Also, perform some test shots to determine the level at which the ISO settings on your camera begin to degrade the quality of the image. Noise will always show in the shadow/dark area’s first.
Be Careful When Doing Long Exposures
Long exposures produce some of the most dramatic photos, but if the exposure is very long, the camera sensor can start to heat up, and the pixels will render improper exposure and colors. You can still carry out long exposures, but again, be wary of how your camera handles the extended exposure period.
Does the picture look very grainy? Experiment to know where your camera starts to struggle. Then ensure that you do not shoot a long exposure for a longer period than whatever works well on your camera. The main point here is to know the precise limits of your gear and shoot within those limits. It’ll ensure high-quality images and easy editing of the pictures.
Check Your Exposure
At the debut of the digital cameras they were bad at rendering highlights correctly. Several photographers would opt to underexpose their images slightly to keep in mind detail in the highlights.
In other words, the shadow areas were very dark, and when you attempted to pull them up in Photoshop, the digital noise would become evident. In fact, experts have solved this issue, and the new generation of the digital sensors does an excellent job of handling shadows and highlights.
Thus, you can expose properly without fear of having problems in the highlights, or noise in the shadows. You can now overexpose a bit so that the shadows are a brighter than normal and then you can pull down all highlights in Photoshop.
Be cautious not to overexpose excessively, watch that you do not clip the highlights since the details may get lost forever.
2. Fixing Noise In Photoshop Or Lightroom:
Once you have taken a shot, you’ll want to open it up in Photoshop or Lightroom to find out how it looks. It’s a brilliant idea to zoom your picture to 100 percent to see the real details of the noise in it. When you make some adjustments, ensure to zoom into 100 percent (1:1 in Lightroom), but also zoom out to see the full photo ensure that the entire thing looks magnificent.
Noise Reduction Workflow In Photoshop And Lightroom Camera Raw
The controls in Photoshop and Lightroom Camera Raw are quite similar, so below is a quick overview of what every slider does and how to utilize them. In Lightroom, you’ll find the Noise reduction tools in the Develop Module. In Camera Raw you’ll find it as a third tab on the right-hand side of your screen. It’s the Detail tab.
The functions of sliders include:
Minimizes luminance noise that’s noise coming from under or overexposed pixels and this can be quite common in long exposures.
Regulates the luminance contrast and it’s suitable for noisy images. Higher values maintain contrast but can deliver noisy blotches or mottling. Lower values provide smoother results but can also have low contrast.
Controls the threshold of luminance noise. It’s useful for noisy images. Higher values keep more detail but can deliver noisier results. Small values provide cleaner results but also eliminate some detail.
Lowers color noise. You can quickly notice in underexposed shadow parts of a photo.
It controls the smoothness of the colors in the picture. It’s useful if you still have some rare color noise in your image after you’ve made all your adjustments above. Use this slider to finish off the noise reduction workflow.
Controls the threshold of color noise. Higher values help to protect thin, detailed color edges but can cause color specks. Lower numbers eliminate color speckles but can cause color bleeding.
So, understanding the ‘digital noise,’ how to avoid it, and what you can do about it will help in enhancing the final quality of your photos.
Hope that helps you in reducing digital noise in your photos.