How to use iso in digital camera photography?

1, ISO is the sensitivity. If ISO is the lowest value in the case of sufficient light, the picture quality can be improved and the picture can be more detailed, especially when it is enlarged twice. The purpose of improving ISO in the case of insufficient light is to make the shutter focus at high speed (called safety shutter) when the hand-held camera does not use tripod to shoot, so as to make the photo clear and sacrifice the image quality. Noise is a light-colored dot with small pixels like dust. The darker the color, the more obvious the ISO is. So the higher the ISO, the louder the noise. Therefore, take photos in an environment with insufficient light conditions, and try to use a tripod to reduce ISO. 2.ISO has nothing to do with background blur. Background blur is called shallow depth of field in photography. The shallower the depth of field, the clearer the background. This is what the aperture does. The larger the aperture, the smaller the aperture and the greater the depth of field. This is because when focusing, there is enough light to ensure the correct exposure of the focus, and the shutter is usually very fast. The photosensitive element has no time to receive the light reflected by the out-of-focus object, which leads to the unreal imaging of the out-of-focus object. This is not only valid for the background, the object in front of the subject is called foreground instead of background, and a large aperture can blur the foreground and background. At this time, it depends on the position arrangement of the subject when the photographer composes the composition. 3. The aperture size is proportional to the shutter speed. The larger the aperture, the faster the shutter speed and the less realistic the picture. The smaller the aperture, the slower the shutter speed and the clearer the picture. Both aperture priority and shutter priority can cause the main body to protrude and the auxiliary body to blur, and the decisive factor is the size of the aperture. These two modes mainly aim at shooting different objects and adopt the most convenient shooting mode. Usually, the aperture is first used to shoot static objects and it is more convenient to control the depth of field (as you said, the degree of background blur), and the shutter is first used to shoot dynamic objects (for example, a slow shutter speed can make the running water look as soft as satin on the screen). Therefore, it is more convenient for the landlord to get the effect of blurring the background. All this is not easy for all models except SLR cameras, such as card machines. I don't know if I have described this, but the landlord understands. . . I think I should understand!