What does exposure value mean?

In photography, exposure value (EV) represents all camera aperture shutter combinations that can give the same exposure. This concept was developed in Germany in 1950s, which tried to simplify the process of choosing between equivalent shooting parameters.

Exposure value can also represent a step difference on the exposure scale, and 1EV corresponds to twice the exposure ratio, which is usually called "first gear".

Exposure value was first represented by symbols. This usage continues to be used in ISO standards, but the abbreviation EV is more common in other places.

Although theoretically all exposure value's same shooting parameters will give the same exposure, they may not be able to take exactly the same photos. Exposure time (shutter speed) determines the degree of motion blur.

Extended data exposure is a combination of aperture, shutter and sensitivity ISO.

There are three factors that can affect whether a photo is exposed correctly: aperture, shutter speed and ISO (sensitivity). Among them, aperture and speed jointly determine the amount of light entering, and ISO determines the photosensitive speed of ISOCCD/CMOS. If the light input is not enough, we can open the aperture or slow down the shutter speed, and if not, we can increase the sensitivity (ISO).

The disadvantage of large aperture is that the resolution is not as good as that of middle aperture. If the shutter speed is reduced, the picture may be pasted, and the quality of the picture will also decrease after the ISO is improved. Without a perfect plan, how to choose should be flexible.

Baidu Encyclopedia-exposure value