Demystifying Digital Image Noise: Causes, Prevention, and Post-Processing Solutions

Clip title: Before you delete a NOISY PHOTO, do THIS! Author / channel: Simon d’Entremont URL: https://www.youtube.com/watch?v=f84Uig3sy04

Summary

This video, presented by professional nature and wildlife photographer Simon d’Entremont, provides a comprehensive guide to understanding and effectively managing noise in digital photographs. The main topic revolves around demystifying image noise, identifying common mistakes photographers make both in the field and during post-processing that exacerbate noise, and offering robust solutions, including specific software recommendations, to produce cleaner images even from high ISO captures.

d’Entremont begins by explaining different types of image noise, such as fixed pattern noise (relevant for astrophotography) and read noise (from sensor electronics in very dark conditions). However, he emphasizes that the most prevalent issue for most photographers is photon noise, or “shot noise.” Using an analogy of rain falling into glasses (photocells on a sensor), he illustrates that a short exposure with fewer “raindrops” (photons) leads to greater variance and thus more noise, while longer exposures or more light result in less variance and a cleaner image due to an improved signal-to-noise ratio. This principle underpins his advice for in-field photography: to reduce noise, photographers should aim to capture more light by using longer shutter speeds, wider apertures, or adding external light sources.

A significant point addressed is the common misconception that high ISO settings create noise. d’Entremont clearly explains that ISO does not add light; it merely brightens an already captured, potentially dark image, similar to turning up the volume on audio. Therefore, a dark image shot at low ISO and brightened in post-processing will exhibit the same noise profile as an image captured brighter at a higher ISO, assuming the actual amount of light hitting the sensor was the same. This debunks the myth that strictly avoiding high ISO necessarily reduces noise if the underlying light capture is insufficient.

In post-processing, d’Entremont highlights two critical mistakes that worsen perceived noise: “pixel peeping” (zooming excessively into an image) and over-cropping. Over-cropping effectively magnifies noise, making it more visible. Additionally, raising shadows in processing tends to amplify noise because darker areas of an image naturally contain fewer photons and are inherently noisier. He advises against over-cropping and suggests adopting processing strategies that work well with darker shadows, such as moody or high-contrast looks. For unavoidable noise, he contrasts basic in-software noise reduction (which often blurs details) with more sophisticated solutions. His recommended tool is DxO PureRAW 6, which he uses as part of his workflow. He praises its advanced demosaicing engine, camera and lens-specific optical corrections, and intelligent DeepPRIME XD3 noise reduction algorithm that differentiates between subject and background, preserving detail while effectively cleaning up noise.

Description

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Tags

photography, photography tips, photography tutorial, digital photography, photography basics, setting the right iso, shutter speed, exposure triangle, learn photography, what is iso, aperture shutter speed and iso tutorial, sharpness, photography tutorials, lens sharpness, digital photography camera, ssharop photos, landscape photography, noisy images, noise reduction, photo editing, wildlife photography, sharp photos, sharp photos in low light, low light photography

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