Noise is an essential part of digital photography and can cause numerous imperfections in the image. It arises due to numerous factors such as incorrect exposure, settings, lighting, and even the condition of the camera.
Noise originates mainly from the image sensor of the camera and can cause the image to appear unclean. It is seen as dust-like particles that are distributed across the image randomly.
The quality of the light is one detrimental factor that causes the occurrence of noise in digital images. Noise is mostly concentrated on the darker and colored portions of the image, as they merge easily into the highlights and whites in the image.
Image noise is usually corrected by using various in-camera settings and through professional picture editing. Eliminating noise from digital images requires a knowhow about the various types of noise, and how they occur in the images. The following are three main types of image noise present in digital images.
Fixed Pattern Noise
Fixed pattern noise is a type of image noise that occurs commonly in digital images. This noise will appear on the images as numerous colored patterns distributed within the image. Fixed pattern noise mostly occurs due to the heating up of the camera sensor. Prolonged usage can cause the image sensor to heat up thereby causing various irregularities in the captured image known as noise.
Fixed pattern noise is most visible in photos that involve long exposures. This type of noise can be avoided by capturing images in a cool atmosphere and letting the camera to rest sufficiently after long exposures.
Random noise is another common image noise that occurs in digital cameras. It occurs mostly due to incorrect settings during the capture of the image such as using high ISO values. Random noise appears mostly when using ISO values as high as the 3200 range. However, most of the modern cameras come with advanced features that allow capturing images with significantly lower amounts of noise even while using higher ISO values. This will allow in significantly reducing the occurrence of random noise in images.
Banding noise is another type of image noise, which is entirely dependent on the type of camera used for capturing the image. Most of the high-end cameras come with advanced noise reduction features that reduce banding noise largely. However, older cameras are highly prone to banding noise especially when captured using high ISO values. Banding noise is mostly found in the shadow regions of the image. Banding noise also occurs while using certain white balance features while capturing the image.