What does the f value of the aperture mean?

The f value is the aperture value, and we use the f value to represent the aperture size.

Aperture is a device used to control the amount of light entering the photosensitive surface of the fuselage through the lens, usually in the lens. We use the f value to represent the aperture size.

Aperture f value = lens focal length/lens aperture diameter According to the above formula, to achieve the same aperture f value, the aperture of a long focal length lens is larger than that of a short focal length lens.

The complete series of aperture values is as follows:

f 1，f 1 .4，f2，f2 .8，f4，f5 .6，f8，f 1 1，f 16，f22，f32，f44，f64 .

function

1, which can adjust the amount of light entering the lens. For example, domestic kittens always shrink their pupils into a line during the day, and automatically Zhang Kaicheng a round hole at night. So in the same way, when taking pictures, the aperture should be narrowed when the light is strong, and the aperture should be opened when the light is dark. That is to say, the smaller the F value (other parameters remain unchanged), the more favorable it is for shooting at night.

The adjusting ring on the rotating lens or the knob on the digital camera body is used to adjust the aperture size.

2. Aperture is the most important factor to determine the depth of field. Small aperture (large aperture value), depth of field, large aperture (small aperture value), depth of field! For example, nearsighted friends, if they don't wear glasses, always habitually squint at things, so they can often see things clearly. To use photographic terminology, this is called: narrowing the aperture (pupil) and increasing the depth of field!