What does exposure compensation of camera mean? How to apply it specifically?

Exposure compensation exposure compensation 1. What is exposure compensation? Exposure compensation is also an exposure control method, generally around 2-3 ev. If the ambient light source is dark, you can increase the exposure value (for example, adjust it to+1EV and +2EV) to highlight the clarity of the picture. In the process of digital camera shooting, if you press the half shutter, a picture similar to the final effect will be displayed on the LCD screen, and all focusing and exposure will start. The exposure at this time is the exposure of the final picture. If the picture is obviously bright or dark, it means that the automatic metering accuracy of the camera has a big deviation, and exposure compensation should be forced, but sometimes the brightness displayed during shooting is different from the actual shooting result. Digital camera can browse the picture immediately after shooting, and at this time, you can see the brightness of the shot picture more accurately, and there will be no discrepancy. If the shooting result is obviously bright or dark, it is necessary to shoot again and force exposure compensation. When the shooting environment is dark and it is necessary to increase the brightness, and the flash can't work, exposure compensation can be carried out to increase the exposure appropriately. When making exposure compensation, if the photo is too dark, the EV value should be increased. Every time the EV value increases, it is 1.0, which is equivalent to doubling the light input. If the photo is too bright, the EV value should be reduced. Every time the EV value is reduced, it is equivalent to doubling the amount of light entering. According to different cameras, the compensation interval can be adjusted in units of 1/2(0.5) or 1/3(0.3). When the photographed white object looks gray or not white enough in the photo, it is necessary to increase the exposure, which simply means "the whiter the more". This seems to run counter to the basic principles and habits of exposure, but it is not. This is because the camera's photometry often focuses on the central subject, and the white subject will make the camera mistakenly think that the environment is very bright, so it is underexposed, which is also a common problem that most beginners are prone to make. Because the shutter time or aperture size of the camera is limited, it is impossible to reach the adjustment range of 2EV all the time, so exposure compensation is not omnipotent, and it is still possible to underexpose in too dark environment. At this time, it is necessary to consider matching the flash or increasing the ISO sensitivity of the camera to improve the brightness of the picture. Almost all digital cameras have the same exposure compensation range, which can be added and subtracted within plus or minus 2EV, but the addition and subtraction are not continuous, but jump at intervals of 1/2EV or 1/3EV. Early old digital cameras, such as Kodak's DC2/KOOC-0/5, were separated by/KOOC-0//2EV, so there were -2.0, -65438 +0.5,-/KOOC-0/.5,-/KOOC-. So there are -2.0, -65438 +0.7,-1,-1.7, -0.3 and +0.3,+1.0,+1.3. Generally speaking, the smaller the brightness contrast of the scene, the more accurate the exposure, otherwise the deviation will increase. There are high and low grades of cameras. If the grade is high, the measurement will be more accurate, and if the grade is low, the deviation will increase. If it is a traditional camera, the film tolerance is relatively large, and the exposure deviation will not be a big problem within a certain range, but the CCD tolerance of a digital camera is relatively small, and a slight exposure deviation may affect the overall effect. In a word, the adjustment of exposure compensation is determined by experience and sensitivity to color. Users must compare the image quality, sharpness, reduction and noise under different exposure compensation in order to take the best photos. Generally speaking, a negative with rich layering can be called correct exposure. Most modern cameras have the function of internal metering. In most cases, shooting according to the data provided by the exposure meter can make most negatives get basically correct exposure. This is because the exposure meter reads 65,438+08% gray tone, and 65,438+08% gray is the average light value in our daily life scenes, such as our skin color. However, the correct exposure is not equal to the best exposure, especially when white or bright objects are dominant in the picture, there will be obvious deviation if shooting only according to the photometric data of the camera, that is to say, the white objects, bright objects and dark objects in the picture are all 18% gray scale, which is naturally unsatisfactory. Therefore, exposure compensation plays an extremely important role in the absence of incident exposure meter or gray board. Our common cameras with automatic exposure function generally have exposure compensation function, while cameras with manual exposure need to compensate exposure by controlling shutter and aperture. From the picture below, we can see the results of different exposures of white objects and black objects. ● Increase the exposure, measure the exposure according to the white tea set, and the main shadow of the picture is dark. Add 0.5EV (half stop) exposure on the basis of the original measurement, improve the main shadow, and add 1EV (1 stop) exposure on the basis of the original measurement, and the white subject will be correctly represented ● Reduce the exposure, and measure the exposure according to the black subject. The light tone of the black subject is reduced by 0.5EV (half stop) exposure on the basis of the original metering, and the tone of the black subject is reduced by 1ev( 1 stop) exposure on the basis of the original metering, so that the black of the subject is correctly represented. As can be seen from the above picture, exposure compensation plays an important role in scene representation. Some experienced photographers often use the words "white plus black minus" to explain the essentials of exposure compensation. Because of the different reflectivity of various scenes, there is no specific standard for compensation range, so photographers should form the habit of carefully observing scenes, analyze the balance and reflectivity between black, white and gray, grasp the exposure essentials they need from thinking and practice, and shoot wonderful works. 2. If the exposure compensation principle is fully automatic, the camera itself has an exposure compensation device, which generally increases or decreases by three levels according to the normal value. The basis of compensation mainly depends on shooting conditions, such as front light or back light, and the exposure of front light, back light and dark light should be increased; For example, under the same lighting conditions, the exposure of blacks will increase by 1 and 2 levels compared with whites; The intensity of the reflected light in the surrounding environment is large, so the exposure can be appropriately reduced, and the exposure can be appropriately increased if it is small. If you set the shutter and aperture manually, you should know that the shutter and aperture determine the exposure. Then, according to the above, the purpose of exposure compensation can be achieved by appropriately increasing or decreasing the shutter speed and expanding or narrowing the aperture. General automatic exposure compensation is to modify the corresponding aperture value. If you want to pursue the dynamic effect of photos, you should use the shutter prerequisite function. That is to say, in addition to controlling the luminous flux, the shutter also has a main function of making photos have special dynamic effects. For example, the shutter speed is fast, which can condense the water column seen by the naked eye into water droplets, while the shutter speed is slow, which can also turn the water column of the same object into a water curtain. If you pursue this, you can fix the shutter first and make the aperture compensate accordingly. If the depth of field is different, we should use the first function of the aperture, that is, fix the aperture first and let the shutter speed make corresponding exposure compensation. 3. Exposure and exposure compensation value (EV) Exposure is defined as how much light hits the camera's sensor. This mainly depends on the camera setting shutter speed and aperture. Exposure value (called Electric) sets the number of camera exposure representatives. We will explain what digital mode is and how to use exposure compensation. Exposure depends on two things: how much light the camera lens sensor transmits and how long the sensor exposure time is. The former is functional value. The aperture of the latter is the function shutter speed. How much is exposure value? This may be a light weight that will touch the sensor. It must be recognized that exposure value is a measure of how the sensor is exposed, not based on the actual impact on the sensor. Exposure value lit the scene independently. For example, double aperture and shutter speed represent the same value. If exposure value is used in a very bright lens during the day or night, each stop value and shutter aperture represent all exposures that may lead to the same occasion. Although exposure value is a combination of values and shutter speed at the same aperture, the picture may be very different (aperture controls the depth of field, while shutter speed controls how much motion is captured). The electric car means that the exposure is set at the aperture f number 1.0 of 0.0. The shutter speed is 1 sec. All others are exposed to some relative values. Numerical values are two cardinal numbers. This means that the EV-7 1 type plus or minus 1- represents that each step of exposure (actual combination, hitting the sensor) is halved or doubled. It is also unlikely. You will find that your absolute setting is exposure value. You don't support input cameras at all, exposure value. But when you will use exposure value to set exposure compensation, the exposure compensation method will determine what is lower or higher than automatic detection. The camera automatic exposure setting is not perfect, and some photos are exposed or above under the scene effect. In this case, exposure compensation can also solve the problem. When you get a useful photo, it is still a little overexposed. When you choose to set the exposure compensation value, plus the current exposure setting, the exposure compensation value usually does not exceed +/-5. For example, compensation-secretly exposing the picture (or reducing the exposure), compensation 2 electric will make light (above exposure). A good example is to use exposure compensation in bright days. By using commercial -0.5ev or IUD to reduce exposure compensation, we can get richer colors and details. Exposure value can also use automatic tagging together. When using automatic exposure, you need to prepare an extra series of pictures for each of you every time you take a picture with a stand camera. 4. What is the difference between exposure compensation and flash compensation by changing IS? O Fill the photo with flash exposure compensation is to fill the photo with built-in flash. "The distance between the object and the background" is the biggest difference between flash exposure compensation and continuous exposure compensation. When the distance between the object and the background is far enough, the exposure compensation of the flash mainly considers the metering mode and the reflectivity of the object, and no longer considers the background, because the brightness change of the flash on the background can be ignored. Ordinary exposure compensation must always consider the brightness of the background. References:

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