What is Noise in Photography?

Noise is generally easy to identify—it consists of pixels with inconsistent, unnatural colors that disrupt image quality. There are two main types of noise commonly found in photos:

1. Device-Generated Noise

• Gaussian Noise: This type of noise appears uniformly across the entire image. It becomes noticeable when increasing ISO, reaching a point where it becomes “unacceptable.”
• Salt and Pepper Noise: Often seen in dark areas of a photo, this type of noise is frequently discussed in photography forums.
• Quantization Noise: Caused by data compression, leading to random artifacts in the image.
• Film Noise: Common in analog photography, this type results from the physical characteristics of film development.
• Anisotropic & Periodic Noise: These appear as structured noise patterns in rows or columns, usually caused by electronic interference. If your sensor is affected by this, it likely needs professional repair.

2. Light-Generated Noise

• Shot Noise: Caused by fluctuations in light photons, leading to variations in image exposure over time. While this is a concern for videographers, it is less critical for photographers.

Understanding noise helps photographers control image quality and optimize camera settings for better results.