Do you know the basic knowledge you have to know when learning SLR - aperture, shutter and their combined use?

The lens is like a person's eye. Maybe you go around in a big circle, and finally realize that photography is just a blink of an eye, a simple combination of aperture and shutter.

1. Aperture

Aperture is a device used to control the amount of light passing through the lens and entering the photosensitive surface of the body. It is usually inside the lens. The size of the aperture is expressed in terms of f value. For a lens that has been manufactured, you cannot change the diameter of the lens at will, but you can control the amount of light passing through the lens by adding a polygonal or circular hole-shaped grating with variable area inside the lens. This device is called an aperture.

In order to accurately control the exposure, the aperture has steps. Common aperture values ??are 1, 1.4, 2, 2.8, 4, 5.6, 8, 11, 16, 22, and 32. Each number here represents one level of aperture, and the difference in light transmission between each level of aperture is doubled. The smaller the number, the greater the amount of light.

2. Shutter

The shutter is the mechanism used by the camera to control the effective exposure time of the photosensitive film. It is an important part of the camera. Its structure, form and function are an important factor in measuring the quality of the camera. Generally speaking, the larger the shutter time range, the better.

In order to accurately control the exposure, the shutter is also arranged in levels. For example, 4 seconds, 2 seconds, 1 second, 1/2 second, 1/4 second, 1/8 second, 1/15 second, 1/30 second, 1/60 second, 1/125 second, 1/250 second, 1/500 second, 1/1000 second, these speeds are basically doubled.

3. The combined use of aperture and shutter

Aperture and shutter have their own numerical values, and there is a corresponding relationship. When shooting, for example, with an aperture of 5.6, the shutter speed should be 1/250 second. If you want to obtain the same exposure, you can make the aperture one step larger, use 4, and the shutter speed one step smaller, use 1/500. Or if the aperture is one step smaller, use 8, and the shutter speed is one step slower, use 1/125 second.

We can use a variety of different aperture and shutter combinations to obtain the same exposure, but the photo effects obtained by each combination are different. For example, in the picture below, the exposure is the same, but the clear range before and after the subject is different.

This involves depth of field, which is the clear range before and after the subject in focus. A large depth of field means a large range of clarity; a small depth of field means a small range of clarity. Applied to aperture, the larger the aperture (the smaller the aperture value), the smaller the depth of field; the smaller the aperture, the larger the depth of field.

If applied to actual shooting, when photographing people, to highlight the subject and blur the background, use a large aperture; when photographing landscapes, if the scenery from near to far is clear, use a small aperture.

The different visual effects of photos are achieved through different combinations of aperture and shutter.