The term dynamic range describes the ratio between the brightest and darkest parts of an image. HDR or high dynamic range, can describe the cameras or techniques you can use to capture a greater dynamic range than SDR (standard dynamic range, a non-HDR format) camera sensors can record.
Most people may be familiar with HDR in terms of video. More and more content creators are producing HDR videos as many of the latest digital video cameras from Sony and Nikon — and even the camera in the iPhone 12 — can shoot in HDR. Currently, streaming services like Amazon Prime Video and Netflix support HDR10 and Dolby Vision HDR formats, but Netflix requires a subscription to their UHD Premium plan. You can also watch HDR TV content with an ultra HD Blu-ray player connected through an HDMI port that supports HDCP 2.2 or later.
To enjoy that video in its full contrast ratio, viewers need high-end 8K or 4K TVs capable of handling HDR content. These include OLED (organic light-emitting diode) screens and QLED (quantum dot light-emitting diode) screens, variants of the common LCD (liquid crystal display) HD TV screens.
For photography, HDR describes a type of photo that captures a dynamic range that can’t be achieved in a single photograph.