High-dynamic-range imaging (HDR) is a process used in photography to capture a greater dynamic range between the lightest and darkest areas of an image. When you take a photo the camera sensor is limited to the amount of detail it can record. Have you ever taken a picture in a brightly lit room only to discover either the room is too dark or the window overexposed lacking detail!
HDR compensates for this loss of detail by taking a series of images at different exposures and combining them together to produce a picture that is representative in both dark and well lit areas.
This is usually done by taking three images of exactly the same scene each at a different shutter speed. This results in an overexposed, normal and underexposed image based on the amount of light getting through to the sensor. It is called bracketing and can also be done by changing the aperture or the ISO.
Many DSLR’s have ‘automatic exposure bracketing’ as a function and you can take three photos with just one click of the shutter, each in different exposures. They can also be combined within the camera and my Sony A77 does this extremely well, creating HDR’s with a more natural look. If your camera doesn’t have AEB you can do this manually by setting your camera on a tripod and varying the exposure times.
I usually shoot 3 to 5 images in RAW and combine them with HDR software. I am able to get more out of a RAW file than JPEG’s although many photographers only use JPEG’s and may disagree!
Compared to a digital sensor the human eye has a much higher dynamic range and HDR would be better used to recreate e.g. the colours lost in a sunset or quite simply enhancing the lost detail.HDR is also commonly used to display images in a way that exaggerates contrast for artistic effect. Unfortunately HDR has gained a bad reputation due to the unrealistic images created.
HDR High Dynamic Range Photography Processing
For combining (post processing) I prefer to use Photomatix and Lightroom. These are amazing applications that are able to combine your images easily and please see my reviews on why I choose to use them.