What is the formula of shutter aperture sensitivity?

The function of the aperture is to determine the amount of light entering the lens. When the shutter is constant:

The smaller the value behind f, the larger the aperture, the more light entering, the brighter the picture, the narrower the focal plane and the more blurred the background of the subject;

The larger the value behind f, the smaller the aperture, the less light entering, the darker the picture, the wider the focal plane, and the clearer the front and back of the subject.

Taking pictures of people is mainly about people's demeanor. The foreground is deep and the background is simple and vague. Then we must cooperate with the reflector to show people's light as silhouette light, and people's face and hair as contour light, which will show people's demeanor more. Usually, the depth of field of landscape photos is very wide. In order to highlight the theme, portrait photos are shot with a small range of depth of field and a large aperture. The smaller the value, the aperture of F4.0 is used.

Set aperture:

Turn on the digital camera and switch the mode to the aperture priority automatic exposure mode AV. You can set the aperture value at will, but if the aperture setting is too large, the contrast and sharpness of the picture will be reduced, so it is better to set F5.6 and F8, while setting the aperture value from F 1 1 will obviously affect the picture.

Aperture mainly changes with aperture value, lens focal length and shooting distance. When taking close-ups, you can set the aperture to F4.0 and F5.6, which is better, the depth of field will be smaller, and the photos will not be sharp.