HDR (High Dynamic Range) imaging is a set of techniques used in photography to reproduce a greater dynamic range of luminosity than standard digital imaging or photographic techniques.
The aim is to present the human eye with a similar range of luminance that is familiar in everyday life. The human eye adjusts constantly to the huge dynamic changes ubiquitous in our environment. The brain continuously interprets this information so that most of us can see in a wide range of light conditions. Most camera sensors, on the other hand, cannot.
HDR is achieved by taking multiple exposures (usually 5 or 7) of the same image and then combining those images in editing software like Photoshopto to create an HDR image. You can view my tutorial on HDR images and Photoshop for Free by taking the “Photoshop Techniques” Course here on YPS.
You can also create HDR images on your iPhone with apps that do all the hard work for you. My favorite HDR iPhone apps in order of preference are:
HDR apps usually take 2 exposures and combine them. Here’s an example done with HDR Fusion.