Noise reduction
Also known as: denoising, image noise reduction, NR, grain reduction
Noise reduction is processing that smooths out the random speckles and grain that appear in photos and videos shot in low light or at high ISO. It trades fine detail for a cleaner image, so heavy noise reduction can leave skin and textures looking soft or waxy.
- Smooths random grain from low light and high ISO
- Trades fine detail for a cleaner image
- Too much creates a soft, waxy look
Where noise comes from
Image noise is random variation in brightness and color, most visible in dark areas and shots taken in dim light. It grows when the camera raises ISO (sensor sensitivity) to compensate for too little light, and on small phone sensors that collect fewer photons per pixel.
Noise reduction analyzes the image and averages out these random fluctuations while trying to preserve real edges and detail. Phones apply it automatically as part of their computational photography pipeline, often blending several frames to cancel noise.
The detail trade-off
Denoising cannot perfectly tell noise from texture, so aggressive settings smear away fine detail — hair, fabric, and foliage turn into smooth blotches sometimes called a "watercolor" or "waxy" look. Light noise can be less distracting than the smearing used to remove it.
Shooting RAW lets you apply gentler, controllable noise reduction afterward instead of accepting the camera's baked-in result. It does not change file size much on its own; it is the source format and resolution that drive storage.