What are the EU values in photography?

It should be EV value: EV (exposure value) value: exposure value. Replace the shutter speed and aperture value with integer values as shown in the following table. The integer value corresponding to the shutter speed is called TV, and the integer value corresponding to the aperture is called AV value. By adding these two values, you can easily get exposure, which is called EV value (that is, exposure value). As long as the EV value is the same, no matter how the shutter speed and aperture are combined, the exposure is the same. Through the combination of different shutters and apertures, the exposure is the same, but their suitable shooting environment and shooting effect are different. For example, if you use the shutter of 1 1 25 seconds and the aperture of f11in sunny conditions, you will get the same exposure as the shutter and aperture of 1/250 seconds and f8 respectively. Shutter priority is similar to aperture priority. We set the shutter speed manually, and the aperture size is automatically matched by the camera. Under normal circumstances, if you shoot manually, the shutter speed should not be lower than1/60s, otherwise the camera will be unstable and the picture will be blurred. Of course, if you have enough power or use a tripod, you don't have to worry about stability. On digital cameras, shutter priority is generally represented by "S". The main application scope of shutter is shooting moving objects and occasions, but it takes a long time to accumulate experience to shoot properly. For example, when shooting walking or fast moving, the shutter speed is set at about 1/250 seconds, so that a relatively clear and jitter-free picture can be obtained; To shoot a faster free fall or flying object, it is necessary to increase the shutter speed to about 1/400 seconds; It takes more than 1/800 seconds to shoot maximum ride. On the contrary, if you want to take some photos that are relatively vague and have another artistic conception, you will get better results by lowering the shutter relatively, such as 1 sec,1/sec and so on. 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 metering 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. Thank you.