What is the iso of digital cameras? The higher the number, the better?

First of all, ISO is called sensitivity on the camera.

In traditional cameras, such as Kodak 100 and 100, the film sensitivity is divided into slow film and high speed film according to the chemical reaction speed of the film to light. Digital camera senses the intensity of incident light as sensitivity through photosensitive element CCD; ISO sensitivity is increased from 100 to 400, and shutter speed is changed from115 seconds to 1/90 seconds. When shooting fast-moving objects, sensitivity and shutter speed should be improved, noise and particles are large, and high image quality requires low sensitivity and shutter speed, especially when shooting still life.

Generally speaking, the lower the ISO value, the finer the particles. Conversely, the higher the ISO value, the thicker it will be. If the ISO value is too high, it can have special effects in sports photography.