What is photometry? Please explain fixed-point metering, multiple metering and center offset metering.

These terms only appear in digital cameras. If you don't play SLR, it doesn't make much sense to understand this ~

No matter ordinary digital camera users or skilled photographers, the higher pursuit of the best shooting effect of photographic works is the same. And a good photographic work depends largely on whether the operator can capture the best exposure. Theoretically, the correct exposure must coordinate the adjustment of shutter speed and aperture. Therefore, we must first measure the brightness of the object to measure the correct exposure. Like traditional cameras, digital cameras also provide a variety of metering methods to help users solve specific problems to meet the different needs of photographers.

As the so-called concrete analysis of specific problems, different shooting environments need to use different metering modes. Now, let's briefly talk about the functional characteristics and suitable shooting environment of the three most commonly used metering modes of digital cameras.

Multi-region evaluation photometry

This is the most commonly used metering mode when we use digital cameras in our daily life, and it is also the automatic default metering mode when most digital cameras shoot. In the process of shooting, the automatic metering system of digital camera will divide the whole picture into several areas, but the segmentation shape and method of each camera are different. After dividing the regions, the metering system determines the weighting ratio of each region according to the picture position of the reference object, and finally determines all the weighted final exposure value. This metering mode considers the overall exposure of the picture more, and tries to make most of the objects in the picture achieve better shooting results. It is mainly used for shooting when there is no strong contrast between shooting objects. Through multi-point sampling and integral operation, the most suitable exposure for the whole picture can be calculated. In the final analysis, this metering mode is a global balanced exposure of the whole scene light, so it is most suitable for general mass shooting activities.

Suitable for shooting purposes: group photos, family photos, general scenery photos, etc.

Group photos, family photos and ordinary scenery photos generally do not require highlighting local scenes, but pay more attention to the harmony and unity of the overall picture effect. Therefore, the regional balance of scene exposure is the first key issue. Therefore, it is most appropriate to take this kind of photos and choose the multi-area evaluation metering mode.

Demonstration example:

This is a photo taken by multi-area evaluation photometry mode. It was sunny and the light was average when shooting. The photographer first selects the appropriate shooting angle with the telephoto lens, then fixes the subject in the central part of the composition picture, and finally shoots with the multi-area evaluation metering mode automatically defaulted by the camera. Because the main advantage of multi-area evaluation photometry is that the overall exposure is better under normal light, such landscape photos can generally meet the satisfaction of users. However, because the light changes quickly, we need to pay attention to some problems in some special situations. For example, if the direct light in the sky is too bright, the strong light will directly affect the photometric reading, making the exposure time too short and destroying the effect. The solution to this problem is actually very simple. The solution is to let the camera lens face down slightly when metering, and try to exclude the brightest part when metering. In this way, the final overall picture can be exposed relatively evenly.

Second, central focus photometry.

This metering mode focuses on the center and strives to make the central object more prominent. But at the same time, the rest of the pictures are average. How much central area to reach depends on different cameras. Center focus photometry can be understood as a flexible way, which not only needs to express the main body of the picture, but also needs to take into account the overall exposure. Compared with multi-area evaluation photometry, it began to focus on highlighting the main body of the picture, but did not give up the appropriate performance of the surrounding environment. Its use value in practical application is far greater than that of multi-area photometry. However, when using this metering mode, we should pay special attention to it, because the camera should move properly, so it is often impossible to decide metering and composition at the same time.

Suitable for shooting purposes: personal travel photos, special scenery photos, etc.

When traveling at home, you should take photos at various scenic spots as a souvenir. At this time, you should not only show that you have been here, but also show that you have been there. At this time, the central focusing photometry of digital camera plays an important role. In addition, taking some special scenery photos also needs to use the central key metering mode. The photos taken by this metering mode can produce a proper sense of hierarchy, and keep the overall picture relatively complete on the premise of highlighting the central image.

Demonstration example:

This photo was taken in central focus metering mode. Because this mode depends on the information of the whole picture to determine the exposure value, but it accounts for a large proportion in the central part, so the exposure of the central main scene is relatively large and the effect is more prominent. Take the subject as the standard when shooting, and let him try his best to achieve the most accurate exposure. At the same time, try to use a large aperture to make the background picture loose and fuzzy, and the main scene is relatively concentrated. This photo clearly reflects these characteristics of central focus photometry. In the photo, the portrait of the child is fixed in the center of the picture. In the case of a little side light, the brighter part of the child's face is the main body of operation, and the brightness of this part is the main body, supplemented by the brightness of other scenes to complete the final metering. After the main exposure adopts central metering, the background scene behind it adopts the method of average metering to avoid the conflict with the main picture due to the prominent effect.

Three-point photometry

Another metering mode of digital cameras is spot metering. When using the spot metering function, the metering area is limited in the center of the picture, which makes the measurement of the exposure required for the most important performance object part in the center of the picture more accurate. Usually, as long as you aim at the medium gray tone of 18% in the scene and aim at a small photometric area, you can get accurate exposure data. For example, when shooting backlight photography, spot metering, a unique metering mode, can provide essential technical support for improving the texture of the subject and enhancing the visual impact. Although spot metering mode is very accurate in measuring local scene exposure, its operation is very simple.

The specific process is to open the operation menu screen of the digital camera, adjust the metering option and set it to "spot metering". Then put the focused subject in the center of the picture, and then press the shutter half. You can determine the exposure while focusing, then press the shutter to adjust the composition, and then press the shutter button completely.

Suitable for shooting purposes: stage photography, personal art photos, special story photos, etc.

The main advantage of spot metering is that even if you are far away from the subject, you can accurately choose partial metering to meet the exposure requirements, which has obvious advantages for those who cannot get close to the subject for metering. In our actual shooting process, we sometimes need to face the special environment of backlight, photometry, reflection and other light, such as taking stage photos. At this time, the difference between the bright outline and the illumination in front of the camera will affect the photographer's field of vision, resulting in underexposure of the scene. The spot metering mode of digital camera is designed to solve this problem. This mode can measure the most accurate exposure by limiting the photometric area of the subject to the center of the picture. Besides being used for shooting stage photography, spot metering mode is an inevitable choice for personal art photos, feature films, instant snapshots and other shooting operations.

Demonstration example:

This photo was taken under the condition of large aperture and close distance, using spot metering mode. Backlight has a great influence on the picture. When shooting, it is necessary to readjust the picture to exclude the light source from the picture and ensure that no glare enters the lens. Then the exposure of the central scene is measured by spot metering mode, and then the composition is re-composed according to the exposure, and the exposure is increased by one and a half to two and a half files. Although spot metering mode can get accurate exposure under the conditions of large contrast, backlight and backlight, we still inevitably need to pay attention to the following points in practical use: 1. When digital cameras use spot metering, it is best to put the focal length of the camera at the telephoto end. 2. It is best to make an exposure combination disk by yourself, which is convenient for the conversion of exposure combination. 3. Do a good job in the conversion and exposure combination of nonstandard exposure numbers.

The real happiness of using digital cameras can only be deeply understood in continuous shooting. The different characteristics and different applications of the above three metering modes provide users with more freedom of choice. In an era of popular DIY, people are more creative than rigid, so there is no established general rule for the use of digital camera metering mode. More surprises and beauty also need you to find and experience in actual shooting. Let's do it together and experience the incomparable happiness brought by digital camera photography.