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This photo has been brightened in Adobe Camera Raw. Sony a7 III | Sony Vario-Tessar T* FE 24-70 mm F4 ZA OSS | F4 | 1/50 sec | ISO 10,000 |
Noise is a common frustration among photographers, especially beginners. Showing up as speckles or tiny color dots in your photographs, noise can spoil what might otherwise be a great photograph by reducing sharpness and adding artifacts that distract from the subject. While the best course of action is to avoid noise to begin with, there are tools to reduce it in your photographs after the fact. In this article, we’ll touch on how to prevent noise and what to do if it’s unavoidable.
How to avoid noise
First and foremost, let’s address a common misconception: high ISOs aren’t the cause of noise in photographs. Noise is much more complicated than that, and is caused by multiple factors. There’s so much going on there, that it’s a topic worthy of a separate article (or two). We won’t be getting into the nitty gritty of what causes noise here, but will touch on ways to reduce its impact.
Maximize exposure
The most effective way to get clean images is to capture as much light as you can. The easiest way to think of this is to use as low an ISO as possible: not because the ISO setting reduces noise but because it means you’ve captured as much light as possible with the aperture and shutter speed, and, as a result, don’t need to bump up the ISO. So think about how long an exposure your subject’s movement and your hand shake will tolerate, and open up your aperture as much as you can. Letting in more light is key to minimizing noise.
Avoid underexposing
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I underexposed this image of a dark grocery store substantially. Sigma BF | Sigma 35mm F2 DG Contemporary | F4.0 | 1/2000 sec | ISO 12,800 Photo: Abby Ferguson |
Brightening the dark image (from the Raw file in Adobe Camera Raw) emphasized the noise caused by not letting in enough light due to a too-fast shutter speed. |
Sometimes the noise you see in edited photos is a result of brightening an image that was underexposed. Brightening overly dark images emphasizes noise that’s already present from a lack of exposure, so it’s best to get your exposure close to correct in-camera. Understanding how to use your light meter and histogram will help you dial in your exposure more accurately in-camera, which will then allow you to optimize image quality with less noise even when editing.
Shoot in Raw
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| This example is a brightened version of the JPEG file shown above, which reveals even greater noise, loss of detail and dynamic range when brightened. |
If you’ve dabbled in photography for much time at all, you’ve likely come across content that tells you to shoot in Raw. That’s because Raw files contain all the data from the sensor. They provide multiple benefits, including greater dynamic range, which provides more flexibility when editing. Both of those help in keeping noise levels in check. The extra data in Raw files also makes it possible to remove more noise in post-processing without losing as much detail as JPEGs.
Use in-camera long exposure noise reduction
Long exposures can also be a culprit for noise because of heat generated by the sensor when it remains active for long periods, resulting in thermal noise and hot pixels. To combat this, many modern cameras offer long exposure noise reduction. This setting captures two photos, one right after the other. The first is the image of the scene, while the second is what’s called a dark frame. It’s taken with the shutter closed, meaning it contains only noise and hot pixel data. Having both allows the camera to subtract information in the dark frame from the first frame, thus reducing noise.
When possible, increase light
One of the main causes of noise is simply not having enough light in a scene. Adding light isn’t always an option, of course, but if you’re in a situation where you can add artificial light or change to a brighter location, you’ll be able to better manage noise in your images. This could be by using a flash (or a constant light source like a lamp), or, if possible, moving your subject towards the light.
Reducing noise in editing
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| Adobe offers an AI-based “denoise” tool in Camera Raw and Lightroom, along with manual noise reduction tools in both programs and Photoshop. |
If you’ve already taken the photo and are seeing higher levels of noise than you’d like, you’re not necessarily out of luck. Traditionally, noise reduction meant loss of sharpness and detail in images, so it was a tradeoff. Now, though, many editing programs offer quite effective noise reduction tools that also preserve detail, and some use AI to maintain sharpness during noise reduction by creating apparent detail. Certain platforms even allow you to selectively reduce noise using masks or brushes, keeping the noise reduction only to areas where it’s needed and keeping sharpness where it’s not.
Our DPREVIEW Tribute:
After nearly 25 years of operation, DPReview closed on 10 April 2023. This difficult decision was part of the annual operating plan review that parent company, Amazon, shared earlier this year.
Over the course of 25 years, DP Review built up a reputation as being one of the most informative places to go for information about that new camera or lens you’re after. DP Review began as an independent reviews site based in the UK in 1998, the brainchild of Philip and Joanna Askey, but it was eventually purchased by Amazon in 2007 and relocated over to Seattle in the USA in 2010.
Cheers DPReview – thanks for the great work and content that guided photographers, videographers and techno junkies the world over!