What is the HDR mode of mobile phone camera mode?

HDR (High Dynamic Range) shooting technology has been widely used for more than a century. As early as 1856, the pioneers of photography realized the effect of high dynamic range by combining several films with the same scene and different exposure, and balanced the light and dark areas in the photo.

Mobile phone HDR refers to high dynamic range compensation. Due to the limited dynamic range of digital photosensitive elements, we will encounter a particularly strong spot-to-light ratio when taking pictures. If the exposure is determined by strong light, it will cause weak light and dark, and the picture will lose its layering. On the contrary, if the exposure is determined according to the weak light, the strong light will be excessively whitened.

HDR technology is to solve this contradiction. Through the imaging processing inside the machine, the strong light part will not be overexposed, and the weak light part will be enhanced to a certain extent. This function has certain practical value. Of course, it can also be processed by software later, but it is certainly not as convenient as the HDR function that comes with the camera.

HDR is the latest and most advanced means to pursue picture fidelity. HDR seems to be a high-end term. In fact, to put it simply, after using HDR technology, the bright places of photos will be brighter and the dark places will be darker, thus making the details between light and dark more obvious. In fact, the effect of HDR photography in daily use is not obvious, because in sunny environment, the details of the object are very clear, so the characteristics of HDR are difficult to show. However, in the case of backlight or dim light, the role of HDR is very obvious. The original chaotic picture suddenly made a lot of HDR pictures clear, recording the brightness value of the actual scene far exceeding 256, and the excess part could not be displayed on the screen.

You can imagine: in photoshop, open a picture taken indoors and out of the window. The part outside the window is overexposed in the strong sunlight, showing a piece of white without too many details. Nothing you can do can stop it. Dimming will only turn white into gray without showing more details. But if you record the same scene with hdr, if you reduce the exposure, the original pure white part will show more details.

HDR is the abbreviation of English High Dynamic Range, which is a post-processing technology. Dynamic range refers to the relative ratio between the highest value and the lowest value of electrical signals, which is reflected in the details that can be displayed in high light areas and dark areas. The larger the dynamic range, the richer the levels. In order to get the picture effect of HDR, it is not enough to take only one photo. It is necessary to take a series of different photos of exposure value and synthesize a high dynamic range photo through software. In the era of film photography, people can increase or decrease the brightness and darkness of photos by local lightening or deepening when developing in darkroom. Although there are few opportunities to contact the darkroom now, you can still find two tools in Photoshop, dimming and deepening, to simulate the effect of local lighting or dimming in the darkroom. Using HDR technology, we can break through the limitation of tolerance, bring the details of photos to an unprecedented level, and further broaden the space of photography creation.

There are also some SLR cameras with HDR function, which can shoot in high light ratio environment. Due to the limitation of dynamic range, ordinary cameras cannot record extremely bright or dark details. Even in the case of high aspect ratio, the photos processed by HDR program can get better levels than ordinary photos, no matter the highlights or dark parts.