What do iso sensitivity, exposure compensation and white balance mean?

Sensitivity, also known as ISO value, is a measure of the sensitivity of negative film to light, which is determined by the measurement of sensitivity and several values, and has recently been standardized by the International Organization for Standardization.

Exposure compensation is an exposure control method, which is generally about 2-3 ev. If the ambient light source is dark, you can increase the exposure value (such as+1EV, +2EV) to highlight the clarity of the picture.

White balance literally means white balance. White balance is an index to describe the white accuracy of the mixed red, green and blue primary colors in the display. White balance is a very important concept in the field of TV camera shooting, through which a series of problems such as color restoration and tone processing can be solved.

Extended data:

Advantages of high sensitivity

The influence of sensitivity on photography is manifested in two aspects.

One is speed. Higher sensitivity can get faster shutter speed and be easier to understand. The second is image quality. The lower the sensitivity, the finer the image quality, the higher the sensitivity and the higher the noise.

High sensitivity defect

When the gain amplitude increases, the noise information is also enlarged accordingly, so the noise becomes more and more obvious in high ISO pictures. At the same time, the number of pixels related to imaging will also double. In order to ensure that the original image information of the imaging size will be expanded, noise is generated. There are fewer photosensitive pixels, and only pixel interpolation can get a complete image in the process of white balance.

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.

Automatic white balance

According to the color temperature measurement system in digital camera, the relative proportion of red light and blue light is measured. Then adjust the exposure according to the secondary data to generate the gains of red, green and blue electrical signals. The biggest advantage of automatic white balance is that it is simple and fast.

Sensitivity exposure compensation white balance