Source:http://www.gearlog.com High dynamic range photos are built from multiple shots of the same image that are merged with special software. The ideal HDR photo is a sandwich of three photos, one shot with the default exposure; one underexposed by two f/stops, meaning it gets one-quarter as much light; and one overexposed by two f/stops, meaning it gets four times as much light.
Many cameras, including most all DSLRs, can be set to bracket the photo, or shoot the normal, under- and over-exposed images either with three rapid clicks of the shutter or one click if you’re using the motor drive. On most cameras, look for the feature called auto-exposure bracketing (AEB). The first shot is normal, the second underexposed, the third overexposed.
If you have the camera on motor-drive and hold the shutter, it will take the three photos, then stop. If not, make sure to take all three photos manually; if you forget and take the second picture of something else a minute later, the camera will make that the underexposed second frame in the sequence of three. If the camera times out and goes to sleep, typically it shuts off AEB.
HDR images work best in these situations:
- Sunny days outdoors
- Snow or beach scenes
- Interiors with windows where you want to show the outdoors details (photo above)
- Night scenes with different levels of illumination over the picture
Conversely, on overcast days with less overall contrast, the camera sensor has enough range to capture all the information your eye sees in a single image. HDR imaging won’t improve the picture much, if at all. HDR software can correct (somewhat) for rustling leaves but not, say, sporting events on sunny days where you’ve keyed on a single player. (An HDR image of the stands would turn out okay.)
If you’ve got people in the photo, try to get them to stand still, and/or use the motor drive so the three photos are shot in a half-second or so. Quick shooting also means trees and leaves don’t move as much. A tripod is nice but not necessary if you’ve got a motor drive. You will need a tripod for nighttime exposures to avoid camera movement and also may need it interior photos. When you bracket exposures, if the normally exposed interior shot is with a shutter speed of 1/60 second, then the bracketed photos will be shot at 1/240 second and 1/15, which is tough to hold steady even if your camera has image stabilization.