Nigelnaturist
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H.D.R. or H.D.R.I. to give its full abbreviation stands for High Dynamic Range Imaging, its a process where by you 2 or more images (usually at least 3) that are taken of the same scene at different exposures, the correct one then over and underexposed, usually at least +-2 stops but can be anything you want, you do this to capture detail in areas of the image that would be either overexposed i.e. skies and shadows, so you underexpose to get more detail in the skies and overexpose for shadow detail, these at the basic level are then combined in software or the darkroom, to produce an image with greater tonal range, to some extent dodging and burning in the darkroom has a similar effect as there is usually detail that a straight forward image lacks.
However the term H.D.R. has become a bit of a cliquish in recent years, in early digital photograph with limit colour/tonal depth it was a way of getting more detail, modern DSLR's with upto 16bit raw file images have a greater tonal range to start with, but it needs software to extract it like the dodging and burning of the darkroom, even so even a 16bit image can lack full tonal range so it is still sometimes useful, the draw back is that a 10megapixel image shot in jpeg is about 4Mb a raw image is 10Mb approx. but you can do so much more with a raw file than a jpeg, for instance colour cast is not an issue as you just set it to the correct temperature, though most A.W.B. (Auto White Balance) in most cameras does a pretty good job.
You can in this image see the under/overexposed images on the right and the original image combined in photomatix.
However the term H.D.R. has become a bit of a cliquish in recent years, in early digital photograph with limit colour/tonal depth it was a way of getting more detail, modern DSLR's with upto 16bit raw file images have a greater tonal range to start with, but it needs software to extract it like the dodging and burning of the darkroom, even so even a 16bit image can lack full tonal range so it is still sometimes useful, the draw back is that a 10megapixel image shot in jpeg is about 4Mb a raw image is 10Mb approx. but you can do so much more with a raw file than a jpeg, for instance colour cast is not an issue as you just set it to the correct temperature, though most A.W.B. (Auto White Balance) in most cameras does a pretty good job.
You can in this image see the under/overexposed images on the right and the original image combined in photomatix.
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