It’s important to lay a good foundation, and you can learn the aperture of photography at home
This year is destined to be an unusual year. For the sake of good health, I believe that everyone has reduced unnecessary outings. If you are a photographer, you may wish to learn some basics at home to lay a good theoretical foundation for shooting in the future. , And if you are already familiar with the basics of photography, you may wish to take a look at it. Quandang is a review.
Today’s article, let’s talk about photography first Common nouns in: aperture.
What is an aperture?
Aperture is a device used to control the amount of light entering the photosensitive surface of the body through the lens. Usually, we use the F value to express the aperture size, and F The smaller the number, the larger the aperture, and the larger the number after F, the smaller the aperture. The aperture priority mode we see on the camera is simply that the camera’s metering system calculates the value of the exposure, and then decides how much shutter speed to use to shoot according to the aperture value we set.
Aperture priority mode
The aperture of a camera has a variety of forms, including fixed, variable, cat-eye, and iris-type instantaneous apertures. Now the aperture of our SLR camera lenses is basically an iris-type instantaneous aperture, which is usually It is composed of multiple overlapping arc-shaped thin metal blades, and the size of the central circular aperture is changed by the clutch of the blades. Generally, the more arc-shaped thin metal blades, the closer the hole shape is to a circle. In addition, the number of aperture blades will also affect the effect of the starburst in the photos we take, and the roundness of the light spots taken through the lens.
When we use the camera to shoot, the iris type instantaneous aperture is usually only It will shrink to the predetermined aperture size at the moment the shutter is opened, and usually stay at the maximum aperture position. This is why when we shoot with a SLR, we will find that the image exposure effect in the viewfinder is different from the actual exposure effect of the photo taken. One of the reasons for the difference.
When we take off the lens and observe the aperture mechanism in the lens separately , You will find that some aperture mechanisms shrink to the minimum aperture position, while others remain at the maximum aperture position. This is related to the design of the lens. The previous lens is equipped with an aperture ring, which can be adjusted manually, but now the aperture mechanism of the lens is generally controlled by the camera’s components, so it will be in different positions before use. It will remain at the maximum aperture position after power on.
The relationship between aperture and depth of field
To talk about the relationship between aperture and depth of field, we must first talk about what depth of field is. Depth of field refers to the sharpness that can be achieved at the front of the camera lens or other imagers The range of the front and back distance of the subject measured by the imaging of the image, if put in plain terms, is the distance of a clear image in the range before and after the focus after the focus is completed. This front and back range is called the depth of field .
There are three factors affecting depth of field, namely aperture, lens focal length and The distance between the camera and the subject, when we discuss the relationship between aperture and depth of field here, it is based on the default that the other two points are fixed. If you want to get the exact depth of field value, we need to bring in the corresponding formula, but for beginners, what needs to be understood is the effect of the aperture on the depth of field, not a more specific optical theory. Because all the photography knowledge we learn serves for creation, it’s okay to be able to shoot without blindly using a large aperture.
aperture 2.8 shutter 1/60 sensitivity 640
Aperture 5 Shutter 1/160 Sensitivity 100
The larger the aperture, the shallower the depth of field, the more obvious the background blur effect, and the more prominent the subject; the smaller the aperture, the greater the depth of field Larger, the less obvious the background blur effect is, it can explain the environment while expressing the main body and highlight the atmosphere. Therefore, we need to adjust the aperture size according to the subject matter we are shooting, such as portraits, still life and other subjects are suitable for shooting with a large aperture, and for some subjects that require background to contrast the environment, such as humanity sweeps the street, you need to reduce the aperture appropriately for shooting.
The effect of aperture on exposure
Aperture also has an effect on the amount of light entering the camera, the amount of light mentioned here, we can understand the impact on the photo exposure effect, we usually say The overexposure and underexposure is a manifestation of the exposure effect. In addition to special creative needs, we generally hope that the photos we take can be correctly exposed, and the parameters that affect the exposure are also determined by three factors.
The three factors of are: aperture, shutter, and sensitivity. As before, when discussing the impact of aperture on exposure, the shutter and sensitivity values are fixed by default.
When we introduced the aperture earlier, we said that the iris aperture passes through the blade The clutch changes the size of the central circular aperture, and the size of this aperture affects the amount of light. In the same time, the larger the aperture, the greater the amount of light entering, and the more light the camera receives, the more “brighter” the perception is directly reflected in the photo. In other words, under other conditions unchanged, the larger the aperture, the brighter the picture, and the smaller the aperture, the darker the picture.
On the basis of learning this knowledge and having a certain understanding, We can simply summarize the role of the aperture as: the larger the aperture, the brighter the picture, the shallower the depth of field, the stronger the background blur, the smaller the aperture, the darker the picture, the greater the depth of field, and the weaker the background blur. After studying on paper, I feel shallow, knowing this matter must be practiced. I hope that you will not blindly pursue large-aperture shooting in future shooting, use a large aperture to highlight the subject, use a small aperture to set the atmosphere, and use the aperture flexibly to improve yourself The purpose of the level of photography.
Author:SINA,If you need to reprint,please indicate the source:http://www.todaycamera.com/camera-reviews/its-important-to-lay-a-good-foundation-and-you-can-learn-the-aperture-of-photography-at-home