What does ipad5 mean by shooting a square and time-lapse photography hdr?

When shooting in a large light ratio environment, ordinary cameras cannot record extremely bright or dark details due to the limitation of dynamic range. 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. What is HDR? HDR is the abbreviation of English High-Dynamic Range, which means "high dynamic range".

After HDR is turned on, it is normal for photos to be slower than ordinary photos, and the processing will be slower.