Science popularization: What is spot metering| Love to play computer games - 上海419贵族宝贝-上海后花园1314-上海品茶网-阿拉爱上海

We often see some metering options in the shooting settings of mobile phones, one of which is "spot metering". Do you know what spot metering means? What's the use? Next, let's discuss it together.

Spot metering, as the name implies, is to measure the light of only one point, which is usually the center of the whole picture, accounting for about 9% of the whole picture. The advantage of this method is that it can measure the light of the most suitable place in a certain picture according to the photographer's preference, without other influences, especially when the light and dark contrast in the scene is strong, Or the subject can measure the light correctly without being disturbed by other nearby lights. For example, when you take a portrait, it is absolutely necessary to spot test the face. When you take photos with large light ratio (such as half of the sky and the other half in the shadow), you need to measure the light of the part you want to expose correctly. Generally speaking, your focus is basically the point you need to measure the light correctly. With a camera with point measurement linkage, the light measurement point is the focus, so you can directly focus on the composition and automatically measure the light. If not, it is necessary to measure the light first and then focus on the composition. (The above content is extracted from Baidu Encyclopedia)

However, the current mobile phones generally have three metering modes: matrix metering, central metering and spot metering. Today, we mainly want to know about spot metering. Other metering modes can be discussed later.

After the point metering mode is enabled, the focus position is the metering point. Now, the focus setting of mobile phones is not the fixed central focus of long ago, but the touch screen focus. The advantage of focusing by touching the screen is that it is easy to get the composition you like, without destroying the composition in order to clear the shooting object. In addition, the focus is the metering point, so it is easier to control the exposure of the picture.

Next, let's look at the daily application of spot metering:

The author here uses Xiaomi 2A as a simple demonstration. These three metering modes are actually the same as the three shooting metering modes mentioned by Xiao Bian. Here we choose "midpoint metering". In fact, this principle is the same as "spot metering". In fact, for mobile phones... the two are the same.

Here, I will make a demonstration with different metering points for the same picture composition. You can pay attention to the changes of the picture exposure. First place the light measuring point in the building outside the window, and then you can see that the surrounding environment is dark except the building outside the window is exposed clearly.

Then, when the light metering points are placed in the dark place of the above picture in the same composition, the exposure will be increased to show the dark place.

Put the metering point in a darker place, and the picture will be brighter. In fact, you should have noticed that if the metering point is placed in a different light and shade area of the viewfinder, it will have a great impact on the exposure of the picture. This is the effect of spot metering. By controlling the metering point, you can get the exposure you want in the same composition. You can't do this if you use central metering or matrix metering. As for the exposure of the above example, it depends on your personal preference.

Here, I would like to talk about the advantages of the metering point and the focus separation operation. This function is relatively new for mobile phone shooting.

When shooting this kind of subject near, but it will light up (here we use a small screen as an example), place the light metering point (remember that the common mobile phone focus and the light metering point are at the same point) on the display, then the lens detects that there is enough light source for the focus, and does not need to increase the exposure, it will reduce the exposure to show the subject. If the exposure drops, the surrounding environment will be very dark.

Then we hope that when we can only move the metering point to make the surrounding environment brighter, the above picture will easily appear. The surrounding environment is bright, but the focus is not right.

As in the above case, if the focus and metering points can be processed separately, the effect will be much better.

Nubia Z5 is used here. For the current smart phones, only the Z5 has a built-in function that can separate the focus and metering points. This function is only available in professional mode. The common mode is also the focus point, which is the metering point.

The green box on the screen is the focus, and the red circle box is the metering point. When you click the screen with your finger, the camera will focus first. At this time, the metering point and the focus point are still at the same point. At this time, we can see that the metering point will get the same situation as Xiaomi 2A on the screen.

Well, now is the main topic. As mentioned above, the professional mode can operate the focus and metering points respectively. At this time, we press the focusing box on the screen with our fingers, and drag it outward, and the light measuring point of Z5 camera will be pulled out. Remember to press the finger on the screen all the time when dragging the light measuring point or focusing, just as you drag the icon to drag the focus/light measuring point. At this time, the editor moves the metering point to the black border of the screen, and the exposure of the picture will be changed.

Then continue to drag the metering point, and the exposure of the picture will be changed. In addition, in the process of dragging the metering point, the focus has always remained unchanged. It is also clearly focused on the computer screen.

I believe you have understood the advantages of separating the focus and metering point. You can adjust the exposure at will without affecting the focus.

The above is the explanation of spot metering and the demonstration of daily application examples. If you are shooting in a large light dark contrast environment, but you don't want to control the picture by adjusting the metering, and you want to show the whole picture completely, you'd better choose to turn on HDR. As for the application of HDR, it can be written before the editor《 What you don't know about HDR 》Take a look.