What does HDR mean in the lens?

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.