What is noise?

The noise suppression ability of digital cameras has always been one of the factors to evaluate the quality of cameras, and images with more noise will be rated as poor quality; Cleaner images are considered to be of better quality.

In fact, the noise of digital images looks very similar to the particles on the film, but it is another matter in the bones. Noise in digital images is inevitable, even if the photographer covers the lens to shoot, there will still be some noise in the images.

When photographers use high sensitivity to shoot images, noise is more obvious. When the camera is exposed for a long time, another kind of noise-hot pixels will appear in the image. Most digital cameras provide two noise reduction functions-high sensitivity noise reduction function and long exposure noise reduction function to reduce the influence of noise on images.

1, high sensitivity noise

Just like shooting the galaxy with high ISO, sometimes it seems that the image is not a big problem.

But after zooming in, you will find that the noise may be very obvious.

High-sensitivity noise is the noise that photographers often encounter. When shooting an image with high sensitivity, some spots and particles will appear in the dark part of the image, and the sharpness will decrease.

High sensitivity noise can be divided into brightness noise and color noise. Brightness noise is usually a gray impurity in the image, which makes the image look not smooth enough. Color noise is the noise in the solid color part of the image, usually magenta or green.