When and how to use exposure compensation?

If you use a camera with an exposure meter or automatic exposure function, you should consider exposure compensation in the following situations:

1, backlight photography. If your subject's back is facing the bright sun, that is, in the case of backlight, exposure compensation must be carried out in order to accurately show the details of the subject.

2. The reflectivity of the subject itself is too high or too low. For example, shooting on the mining face of a coal mine, or shooting a bride wearing a white wedding dress in a high-profile background, if the exposure given by the exposure instrument is not compensated, then the dark coal and white skirt recorded on the film may be the same gray tone of 18%.

3. Reciprocal exchange rate is invalid. If the exposure time is too long (more than l/ 10 second) or too short (less than11000 second), the exposure curve of ordinary film will be distorted. If you still shoot according to the exposure combination given by the exposure meter, there will be underexposure. If you use color film, there will be problems of color saturation and color temperature deviation.

4. Shoot moving objects in extremely weak light. Sometimes the light at the shooting scene is particularly weak, the artificial light illumination is insufficient, the subject is moving, and the film sensitivity in the camera can not meet the requirements of spotlight. At this time, it is also necessary to make compensation, that is, reduce the given exposure within the allowable range, control the number of steps to reduce the exposure during development and carry out forced development (or "sensitized development"), and also get a clear negative.

Generally speaking, exposure compensation is white plus black minus. In a white environment, the luminosity is low and needs to be increased, and vice versa.

Extended data:

The role of exposure compensation:

When the shooting environment is dark, 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, you should lower the EV value. 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, it is necessary to increase the exposure, which is simply "the whiter the more", which runs counter to the basic principles and habits of exposure. Actually, it's not, 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, resulting in underexposure, 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.

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