Teach you to understand the imaging differences of aperture size
- Dec 02, 2019
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Many people ask me how I should buy a camera. At this time, I usually ask each other for their use first. Not surprisingly, the vast majority of people just hope that the photos will have beautiful scattered scenes, so that the photos can be taken beautiful. But you know what? Even if you buy a very good and high-end SLR camera, you may not start a happy photography trip of "taking beautiful pictures at random", for the reason that you can't use it. Nevertheless, don't be discouraged, as long as you buy a certain level of cameras (a picture of a meteoric star, basically as long as the operation is right, you can take beautiful pictures! Today we're going to teach you the relationship between camera aperture and photo imaging. In short, how to set it so that you can easily take scattered and star-spangled photos! Previously, some very bad stores would use the phrase "this is the only way to shoot a scattered scene" or "this lens is the only star" to frighten girls, which is very angry! Please note that as long as you buy a camera with meteoric discharging parts, each lens can shoot astigmatism and stars! Above is a detailed photograph of the aperture. Each lens has a different aperture, but its function is the same (limiting the amount of light entering the camera)! In order to make this teaching easier to understand, so I will explain the effect of aperture numerical value on photographs and the applicable occasions. If you can't read it once, remember it. Then I suggest you put this article away and review it at any time so that you won't forget it! _________. Before you start, remember a super-super basic concept about aperture: the larger the aperture, the more light enters, the brighter the photo takes at the same shutter time; conversely, the smaller the aperture, the darker it becomes. I won't mention this concept later, because it's a very basic concept. You can imagine that if you close your eyes a little, it's darker outside, and if you open your eyes, it's brighter. That's probably the concept. So the bigger the aperture is, the less likely it is to be shocked by hand. That's because the larger the aperture is, the faster the shutter will be and the effect of your hand shocks will be avoided. This section will be explained in more detail later in the shutter speed section.，；。
Many people buy SLRs for only one purpose, that is, to take such scattered photos as the one below. But more consumers are disappointed that their cameras are not good enough. If you think so, you will soon become a fat sheep in the camera shop. Even with the cheapest camera head (usually only a few hundred pieces of the lens attached to the bill), the maximum aperture will be at least F4, to the extent that the photograph will be scattered.
As long as the aperture is larger than F4 (the smaller the number is, the larger the aperture is), the image will be blurred as shown above due to optical limitation. The width of the blurred band will be wider as the aperture is larger. In short, when the aperture is larger, the clearer part will be less (only the camera will focus on it). The smaller the aperture, the more clear the part and the less blurred the block. Does that make it clear to everyone? If you want to have beautiful scattered scenery like the first tone above, then you'd better open your aperture to more than f4, so that you can easily take beautiful scattered scenery photos! In addition, clear areas like the one above are generally called "depth of field". Therefore, the smaller clear areas under large aperture are called "shallow depth of field". The larger the aperture, the shallower the depth of field will be under the same aperture. Therefore, the smaller aperture can be used to obtain scattered photos.
So where does a large aperture fit/not fit? Let us give an example:
In the following picture, the protagonist I want to highlight is Shell (the purple-haired one) standing in front of me, and the personnels behind me are just background-like beings. At this time, I just need to open the aperture (this photo is f6.3, the whole fuselage depth of field is shallow) to make the rear deacon scattered, so that you can see the protagonist I want to highlight at a glance. This is also very suitable for shooting food, small things, by using a large aperture to disperse objects outside the theme, you can effectively highlight the protagonist you want to show.
In fact, the greatest use of large aperture is to produce scattered scenery, and scattered photographs are most suitable for decorating literature and art. As long as you take a picture with unknown meaning and add a few words with unknown meaning, you can immediately produce a very literary and artistic fresh look (fog!). Remember, once you buy a camera with the word "SLR" in its name, you can basically produce pictures like the one above by adjusting the aperture. Never listen to the myth that "you have to buy this to shoot a scattered scene".
Believe that smart as you all, see here should already know why the big aperture is not suitable for group photography, right? Because the depth of field of a large aperture is too shallow, when you focus on one person's face, there must be another poor person who is left out of the depth of field and becomes blurred. The following picture is a failed photo. Because the aperture is too large (f3.5), the only person who can be clearly photographed in the photo is the principal (the white Tang dress), and the others around him are not clear. If you are used to taking photos with a large aperture, you must remember to shrink when you take pictures of more than two people. A small aperture to F8 (or smaller) will prevent the unfocused person from turning into a poor blurred person.
When the aperture is narrowed, it looks like the image above from the front. It will use the aperture blade to shrink the inside of the lens to a small hole (f16 above). At this time, the photograph will get more details and deeper "depth of field" than the large aperture. In short, there will be less scattered field.
First, let's look at the difference between large aperture and small aperture. The following picture is taken by the f2.8 aperture. You can see that except for the nose and eyes of the grass-mud horse building blocks, the rest of the area is not clear, and even the clarity of the clear area is not very high (compared with the figure below). This is what I said earlier: "The large aperture has astigmatism, but fine." Savings are poor. The reason for this phenomenon is that when the aperture is large, more lens area will be used, and it is usually difficult for ordinary lenses to achieve the "excellent" state of the whole lens, so it is inevitable that full aperture will cause deterioration of the picture quality. If you see the comment that "full aperture is still good", usually that one. The lens is a very high-end and noble lens. The following picture is taken by shrinking the aperture to the small aperture of f14. Under the small aperture, not only the whole grass-mud horse head is very clear, but also the back and foot parts are quite clear. The surface texture of the whole building block can also be better displayed. The detail clarity of the whole picture is also better than that of f2. 8 is even higher. This is "small aperture has less scattered scenery and more details". Do you remember that? If you don't remember, you can use four fingers like me to make small holes (simulate the small aperture state) as shown above and look out, you will find that when you shrink to a certain extent, even without glasses, you can see small characters in the distance, although the principle is different from that of small aperture, but the principle is not the same as that of small aperture. In this way, you can remember that "small aperture has less scattering and more details".
What can a small aperture do? For my most commonly used purposes, there are three types:
The so-called "star" means that when you shoot a bright spot (such as a street lamp), you will produce the same prickly light as the above picture. A lot of people mistakenly think that the star is made by special lens. In fact, this is not right. Just like the asterisk in front of you, as long as you set the aperture to the correct value, every lens can shoot the stars! Generally speaking, as long as you zoom the lens to f10, you can shoot a short "spine" star, and the smaller the aperture is (the larger the number is), the longer the spine of the star will be. Above is the star captured by zooming the aperture to f22. Even the flash of the iPhone can shoot the star captured. Is it super simple?
In the following picture, we want Shell and Sebastian to be clear at the same time. It's a concept of "group photo (more than two people)". Therefore, it is not appropriate to widen the aperture at this time, at least to shrink to F8 in order to bring all the details you want to take into the picture and maintain the clearest state. In the following picture, not only the faces of the two people are very clear, but also the coffee cup and the wallpaper pattern on the back can maintain a clear state, which is achieved by reducing the aperture. In addition, if you go to famous scenic spots to take pictures, please narrow the aperture and take pictures again. Otherwise, each picture is only clear to you. The leaning tower of Pisa behind the tower of Paris is not clear. Why don't you take pictures in Da'an Forest Park?
Keep in mind that when the aperture is small, more details can be taken and the picture will be clearer. When we are shooting small things, we usually want to take more details, such as the headphone plug shown below is a good example. Headphone plugs are only about four centimeters long, and it is absolutely impossible to use a large aperture to photograph all the details above. Not only will the details be less, but also because the depth of field is too shallow, the problems of logo clarity (middle section) and plug part (front section) are not clear. So at this point I will zoom in to F14 to get more details and deeper depth of field to make the picture clearer. Generally speaking, all lenses have the best picture quality around f8. As the saying goes, "f8 without rotten mirror" is exaggerated, but it is also the best picture quality at f8. Why not minimize the aperture? This is because when the aperture is small to a certain extent (such as f22), the quality of the picture will deteriorate because of the problems of light diffraction, so it is not that the aperture can be infinitely reduced to make the quality of the picture infinitely better. Generally, when I pursue the details of the quality of the picture, I always turn between F8 and f14. Of course, different lenses will have different appropriate values. Personal experience is for reference only.
Photography is a game of manipulating light and shadow, so knowing the aperture and shutter is the first step to play photography well. Before I understand the relationship and application between them, I basically regard it as a devil's devil's way to learn other skills. The above teaching is mainly to give you a basic concept, so that you can first understand the difference between the size of aperture, as to how the actual photography will be, but also ask you to take your camera to the actual outdoor shooting to see, learning or through practice in order to let you really absorb these knowledge.