Camera aperture, why is the smaller the value, the larger the aperture?

Aperture 1 maximum, and other values are its denominator, so the larger the denominator, the smaller the aperture. Specifically,

The aperture value (f) is a relative value obtained from the focal length (f) of the lens/the light passing diameter (d) of the lens.

The formula is: F=f/D

The larger the lens light passing diameter (d), the smaller the aperture value (f), so the light entering amount of F 1.8 aperture is larger than that of F2.4 aperture.

This is one of the representations, and sometimes the focal length/aperture value is used to represent the aperture size.

The formula is: f/f = d.

The smaller the aperture value (f), the larger the lens light passing diameter (d), so the light input of f/ 1.8 aperture is larger than that of f/2.4 aperture.

Extended data

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!

References:

Baidu encyclopedia-aperture