Is f an aperture? The bigger the f, the bigger the aperture?

Aperture is the device that controls the light in the camera lens, because the image is projected onto the film through the light and shadow passing through the lens. In order to control the amount of light reaching the film, it can be adjusted by opening the aperture. The size of the aperture center opening represents the aperture value, which is usually expressed by f+ value. The smaller the value, the larger the aperture opening, and the more light enters, and vice versa. Usually when shooting, "opening the aperture" means lowering the aperture value and opening the aperture, such as from F5.6 to F4, or from F2.8 Similarly, "turn down the aperture" means turning the aperture up and down, for example, turning the aperture from F5.6 to F8 or F 1 1. This conventional statement is just the opposite of the aperture value marked on the lens, so be careful not to make a mistake.

Shutter is a device for controlling exposure time in camera. Commonly used 135 SLR cameras generally use focal plane shutter. The focal plane shutter usually has two curtains, a front curtain and a rear curtain, which are driven horizontally or vertically through the film plane by a taut spring device. There used to be many horizontal focal plane shutters, but now almost all of them have been replaced by vertical shutters. When the shutter button is pressed, the front curtain starts to move from top to bottom, and then a certain gap is reserved according to the shutter speed, followed by Hou Lian, so that light is projected onto the film from the reserved gap between the front curtain and the Hou Lian, and the film is sensitized. The wider the gap, the more light passes, and the narrower the gap, the less light passes. The faster the shutter speed, the narrower the gap, and the slower the shutter speed, the wider the gap. This is how the focal plane shutter adjusts the amount of light according to the length of time. We can see it in the marking order of shutter speed, such as 1/4, 1/8,115, 1/30, 1/60,1/. It is not difficult to see that there is a multiple relationship between the two, which refers to the exposure time of a fraction of a second. For example, 1/30 seconds is twice as much as 1/60 seconds, and the amount of light passing through the shutter is twice as much. On the contrary, 1/30 seconds is half the time of115 seconds, and the amount of light passing through the shutter is doubled.

Aperture and shutter are devices for adjusting and controlling exposure. They are multiplying or multiplying, and this relationship can be combined in different ways to get the same exposure. For example, when the apertures F8 and 1/30s are correct exposure value, if the apertures F5.6, 1/60s or F 1 115s are combined, they will get the same exposure. So the photographer can choose the light and shutter speed according to his own purpose.

Aperture (aperture)

Aperture is one of the important mechanisms that affect the exposure of a photo. It usually consists of 5 to 9 pieces of metal. It can be composed of apertures of different sizes to control how much light can enter the lens.

The size of the aperture is generally composed of F+ number or 1:XX, such as F2.8, F32, 1: 2.8, 1: 32 ... and so on. Among them, 2.8, 4, 5.6...32 are called aperture values. Every time the aperture is increased (for example, F4-> f 2.8 will double the light input, that is, the light input of F.28 is twice that of F4 (1: 2.8 >: 1:4).

In other words, the smaller the value, the larger the aperture, and vice versa (the inverse ratio is very important, don't make a mistake). The larger the aperture value, the higher the shutter can be kept in a dark environment. Of course, the better, but the price is relatively expensive.

In order to calculate the exposure value in actual photography, the scale value corresponding to the aperture value indicates the light passing ability of the lens.

Because the aperture value changes in multiples of 2, if the aperture value is directly used to represent the luminous flux of the lens, it will be difficult to calculate the exposure value in actual photography. Aperture Value is usually expressed by AV (abbreviation of "aperture value" in English) and by simple scale value, which provides convenience for calculating exposure value in actual photography. See table for the corresponding relationship between aperture value (AV) and aperture value (F).

Aperture value (AV) 0 1 2 3 4 5 6 7 8 9 10

Aperture value (f)11422.845.681162232