Types of Noise in Photography
Luminance Noise
Luminance noise is the variation in brightness of individual pixels that creates a characteristic grainy structure in a photograph. Noise in photographs is often compared to grain in analogue photography.
Unlike chromatic noise, luminance noise can sometimes add an artistic touch to photographs, especially in black and white photography.
Chromatic Noise
Chromatic noise manifests itself as randomly distributed coloured dots in a photograph, particularly visible in the dark areas of the image. This type of noise is usually more problematic than luminance noise, as it introduces unwanted colours into the image, which can significantly reduce its quality.
Where Does Noise Come From?
High ISO
ISO is one of the main contributors to noise. The higher the ISO value, the more likely there is to be noise in photography. This is because increasing the sensitivity of the sensor involves an amplification of the electrical signal, which also leads to an amplification of noise.
Long Exposure Times
During long exposures, the camera sensor heats up, which can lead to so-called thermal noise. This photo noise is particularly noticeable during night photography or astrophotography, where exposure times can reach tens of seconds or even minutes.
Sensor Quality
The size and quality of the sensor have a significant impact on the noise in the images. In general, the larger the sensor and the larger the pixels, the better it handles noise. Therefore, full-frame cameras usually offer better image quality at high ISOs than cameras with smaller sensors.
