One of the topics we cover is HDR or high dynamic range photography. This is a technique that uses Photoshop or specialized software to merge together multiple photographs that have different highlights and shadows (exposure value), in order to make one image that uses the best of all the exposures. This style of photography is well suited to creating scenic or landscape photographs where the foreground has different exposure than the background.
Digital cameras use chips to record information on. These chips have limitations and cant properly record all the information in an exposure with a wide range of light values. In simple terms this means the chip cant record accurately the both the colors of a foreground subject and the sky. The range is to much. In most cases the foreground will look right but the sky or background is overexposed and washed out. When we use HDR techniques we are able to fix this.
Here is how it works. Start by composing an image in the camera of a desired scenic view. Use the camera menu options. Each manufacturer has different settings and menu options and set to auto bracket. There is a control dial that will let you set 3,5,7, or 9 exposures. The dial also lets you control the range of change like 1/3 stop, 1/2 stop, or 1 full stop. I select five stops, at 1 stop increments. The idea is to take several photographs from the same exact location and vary the shutter speed. To do this set the camera on Aperture control at F-8 and let the camera set the shutter speed. Once set I will take five photographs. The first will be at the right exposure, the nest two will be lower, and last two will be higher.
Once the images are downloaded into the computer we use a tool in Bridge called Merge to HDR. The software takes the five exposures and uses all the best highlight and shadow detail from each image to make the foreground, mid ground, and background look their best.