Each camera has its own capabilities and characteristics. The concept of ISO is found in the instructions for each camera, figuring out how to use it correctly and what it is, you can significantly improve your own pictures.
ISO concept
ISO is the light sensitivity of your camera, or rather, the sensitivity to the perception of light from the camera's matrix. That is, if the ISO is 200, then less light will enter the matrix per unit of time than in the same time with the sensitivity value of 3200. The higher the sensitivity of the matrix, the clearer pictures you can take, but you should not assume that clearer pictures it's always good. The more ISO you can set on your camera, the more background noise appears in your images.
The standard ISO values are: 100, 200, 400, 800, 1600, 3200. And the noise appearing in the pictures is multi-colored bright points in the photographs, which are very different in color from the neighboring ones. Due to such noise, the picture looks like a photo taken with a 0.3 megapixel camera in a 2006 phone.
However, the ISO system was created for film cameras. In digital cameras, this parameter seems to correlate with the resulting exposure of the pictures on it and similar characteristics of the film apparatus. Therefore, this parameter on digital cameras has become fully called "ISO equivalent sensitivity". And it is expressed in ISO units for a film camera for the convenience of photographers.
How to use light sensitivity correctly
If you are photographing in an illuminated place, where enough light can enter the camera's matrix in a small amount of time, then it is worth setting the ISO to a small mark. If it is dark in the room, or you shoot in the late evening, then the value of light sensitivity should be several times higher. However, it's always worth taking a few test shots and finding the best solution.
Do not forget that for pictures at night, it is important to open the aperture so that more light can also enter the camera's sensor. If you are working with a tripod and static objects, then it is better to set the minimum ISO, but increase the camera lag. If you want to reduce the amount of noise in your photos, you can also use a flash to add light to your photo.
The setting of light sensitivity also depends on the size of your camera's matrix, if you have a fairly simple camera without interchangeable optics, then the maximum value for you is ISO 800. If you set this parameter higher, then any photo will be overwhelmed with unnecessary noise. On DSLR cameras, which have the best shooting parameters, ISO 1600 and 3200 can be used.
