Basic introduction of SLR photography ⑥ focusing

A common problem for beginners in photography is that when shooting, they will find that the shutter button can't be pressed and the lens keeps clicking. This is the case that the camera is not focused successfully. As we all know, half pressing the shutter button is focusing. You can't press the shutter button if the camera is out of focus.

What is focus?

Focusing is also called focusing. The official explanation for focusing is that the process of changing the object distance and distance position through the camera focusing mechanism is focusing.

The fun of SLR is that more control details can be decided by you, and you can see which part you want, and the control is very accurate.

Auto focus mode/manual focus mode

There are two kinds of focusing methods, one is automatic focusing and the other is manual focusing. Auto focus is AF, and manual focus is MF.

Manual focusing:

In some cases, for example, the scene is too dark and the subject lacks a clear contrast area, such as a monochrome wall. When shooting through a net or cage, the autofocus system of the fuselage will fail, and the autofocus of the camera will not work well, resulting in our common situation of not pressing the shutter. In this shooting situation, the effect of manual focusing will be better.

Manual focusing is to focus manually by rotating the focus ring on the lens. Before manual focusing, switch the focusing mode to manual focusing (MF), rotate the focusing ring back and forth, and confirm whether the subject becomes clear with naked eyes in the viewfinder. When it is clear, it means that the focus is accurate.

Although manual is not as convenient as automatic, automatic focusing is by no means omnipotent. Manual focusing is also a basic skill that photographers need to master. Familiar with manual focusing and skilled use of manual focusing will bring convenience to some shooting to some extent. Especially when shooting macro, manual focusing is usually used.

Auto focus:

Select autofocus mode (AF), and just press the shutter button to start autofocus. After half-pressing the shutter, the camera automatically confirms the focal length. From the viewfinder, we can see that the scene changes from blurred to clear, and the focus in the viewfinder of the camera changes from red to green, and a buzzer sounds to complete the focus and lock the focus. This is the action of camera autofocus.

As long as you keep your finger in the button half-pressed state, the focal length will be locked at the current position. After locking, we can re-compose the picture and press the shutter completely to take pictures. Remember, the movement here is to move the composition up and down, not back and forth. )

The advantage of autofocus is fast and fast, but manual focusing is more accurate.

Auto focus (AF) is also divided into three modes, namely AF-S, AF-C and AF-A..

Single autofocus

When the distance between the user and the subject is fixed and the object is stationary, single autofocus can be used, which is also the most commonly used focusing method. Different topics choose different focusing points and focusing methods. Different topics choose different focusing points and focusing methods. Usually, you can't press the shutter button if the camera is not in focus correctly.

Single autofocus is suitable for still life, scenery, people, flowers and so on.

Artificial intelligence servo autofocus

Artificial intelligence servo autofocus is usually used in sports photography. After the camera is focused, the focusing system is still in working condition. As long as we keep the camera's focus frame always on the subject, the camera can ensure that the focus is always clear. When shooting a moving object, if the subject keeps moving towards the camera, as long as the photographer fixes the focus on the subject and keeps pressing the shutter button half-way, the camera will keep in focus. Usually, this focusing mode will work better with continuous shooting. In addition, in this mode, as long as the photographer presses the shutter button completely, the camera will take pictures, regardless of whether the focus of the subject is accurate or not.

Continuous autofocus is suitable for sports, racing cars and dynamic objects. , and friends' commonly used focus photos are also taken using this focus mode.

Artificial intelligence autofocus

Since there is a single autofocus mode suitable for shooting still scenes and an artificial intelligence servo autofocus mode suitable for shooting moving objects, why is there a third autofocus mode-artificial intelligence autofocus mode?

That's because the object we shoot is likely to move suddenly (such as shooting children or pets), and it takes a lot of power to use artificial intelligence servo autofocus, so the artificial intelligence autofocus mode came into being. It combines the advantages of single autofocus and artificial intelligence servo autofocus, automatically selects the focusing mode according to the moving speed of the object, selects single autofocus when the object remains stationary, and selects artificial intelligence servo autofocus when the object moves.

Choice of focus:

1. Single point focusing

Refers to focusing on a certain part of the subject, so that this part presents a high degree of clarity. Single-point focusing is suitable for shooting portraits, landscapes, still life and other subjects.

For example, when taking portraits, the focus is usually on people's eyes, so that people's eyes and faces will be very clear and sharp.

2. Multi-focus

Multi-focus means that the camera is aimed at the subject, and the focus in the camera will automatically photograph some parts of the subject, making the subject relatively clear in the picture.

When shooting, you can see that multiple focus frames light up at the same time in the viewfinder, and it will give priority to the object with the closest distance and the largest contrast.

The advantage of multifocal is its wide coverage, which is very suitable for shooting big scenes, buildings, people's memorial halls, sports and so on.

For example, when shooting a runner, multifocal can effectively fix the focus on the athlete.

Three. Number of focal points

At present, the number of camera focus is very large, and many camera manufacturers will also use focus as a publicity point. Generally, cameras with focus at 7 o'clock, 9 o'clock and 1 1 are entry cameras, with focus at1,mid-range cameras at 5 1 and high-end cameras at 6 1.

So, the more focal points of the camera, the better and more accurate the focusing performance?

In fact, this view is a bit too absolute. More focus points can only show that the focus system has a wider recognition range and is more conducive to shooting moving objects. In other words, when shooting dynamic subjects and big scenes, the more you focus, the more you can improve the shooting efficiency. In daily photography, the amount of focus does not have much influence on ordinary photographers. When shooting a static subject, you don't need to use a lot of focus points. You can choose a smaller number of focus points, which will save shooting time.

Simply put, it is single-point static focusing and multi-point dynamic focusing. No matter how many points there are, the picture has only one focus or focal plane.

There is no shortcut to photography, let alone a quick one in a day or two. What I can do is to share my accumulated experience with you. I hope you can shoot more and practice more, and keep improving. Let's study together and make progress together.

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