HDR Photos are fun to shoot, because you can do so much with them. Each photo consists of a layer of several photos taken at a different exposure to catch the details in different light levels. Low exposure will capture the details in high lit areas and high exposure will capture the detail in low lit areas. The photos taken in the mid range will capture the the details in between. When the photos are stacked you end up with a true 64 bit image that has details in all areas of the photograph.