This technique has been around since the 1950’s with film and uses a minimum of three (up to 5) exposures separated by 2 stops each. A tripod is necessary, as well as a still subject or scene. The three images are then stacked using software. The benefit is a greater tonal range and detail in the subject that cant be obtained with a single exposure. I used this technique for this image of an old farm truck in a field to bring out the detail and texture in the rusted body of the truck.
HDR Photography Photo Workshop (Wiley's Photo Workshop Series)