What do you think of the histogram?

I believe that friends who like photography are familiar with histograms, but how should we treat histograms? I searched an article below, which may be helpful to you.

Compared with traditional cameras, digital cameras have a very practical function, that is, histogram display function. Histogram is a tool to determine the exposure of photos through the exposure histogram displayed on LCD. We can intuitively see the exposure of the photos taken through the horizontal axis and vertical axis of the histogram, which can bring great convenience to photographers when shooting. ?

Compared with the pixels of existing digital cameras, the LCD screen used for framing or framing is often only a few hundred thousand pixels, and the display size is not large. Therefore, on this small LCD screen, it is generally impossible to fully show the details of the photos. Many times, even if the photos are not exposed correctly, it is difficult to reflect them on the LCD. The built-in exposure bar graph of digital camera provides a good method for photographers to check whether the exposure is accurate or not. The coordinate diagram in the histogram is the tone curve of the digital photo, which represents the tone distribution of the image. The horizontal axis of the histogram is 256 gray levels: the left end is 0, the middle is 127, and the right end is 255. The vertical axis shows the number of pixels that make up each tone. The higher the line, the more pixel information there is. ?

The horizontal axis of the histogram represents the number of pixels in the photo from dark to bright from left to right. The histogram with accurate exposure is distributed from left to right, with light and dark details. At the same time, there will be no pixel overflow on both sides of the histogram. As shown in figure 1. The vertical axis of the histogram represents the area occupied by the corresponding part of the picture. The higher the peak value, the more pixels there are in the bright and dark values. ?

Figure 1 correct exposure.

In the process of shooting, if the left part of the histogram is very high and the right part is very low, it means that the picture is dark and the exposure should be increased. As shown in figure 2, the exposure is insufficient.

Figure 2 Underexposure

If the right half of the histogram is high and the left half is low, it means that the picture is bright and the exposure should be reduced. As shown in Figure 3, the exposure is over.

Figure 3 Overexposure

? When the curve in the histogram is biased to one side, it may be that there is something wrong with the exposure. At this time, you should adjust the corresponding exposure value and take a new picture, as shown in the figure. Remember the complementary light principle of black-and-white subtraction when shooting, or you can use the surround exposure mode of digital camera to shoot. These are all ways to get accurate exposure.

By looking at the histogram, we can also judge the contrast of the photos. When all the colors in the histogram are gathered in the middle and there is no vertical display on both sides, the contrast of this photo will be too low and the details will be difficult to be recognized by the naked eye. For example, Figure 4 shows a low contrast.

Fig. 4 Histogram of Contrast Deficiency Curve