From: ir@ene.nu   
      
   On Sat, 29 Jul 2006 08:29:54 -0400, Frederick Burroughs   
    wrote:   
      
   >Bracketing is the first step. Most digital cameras will do it. It is   
   >impossible for most cameras to capture all the tones in the real world   
   >in a single exposure. It is technically impossible. But if you set your   
   >exposure and allow the camera to bracket the exposure, you get several   
   >exposures; the one you set, plus some at longer, and some at shorter   
   >exposure times (shutter speeds). HDR software combines the multiple   
   >exposure into a single photograph of high dynamic/tonal range that more   
   >closely approximates the "real world," as seen by the human eye.   
   >   
   >The software dramatically increases the dynamic range. The result is   
   >very good detail in both the light and dark areas, and in the transition   
   >between the lightest and darkest areas. This is done by (greatly)   
   >increasing the information stored in each pixel. Because most computer   
   >monitors (and printers) are limited in the pixel size they display, the   
   >HDR photograph must be converted back into a form that will display   
   >correctly. There is some heavy duty theory and computer processing   
   >involved in these techniques.   
   >   
   >The result can be an apparent *loss* of contrast, without some judicious   
   >photo editing. I think this results from the increased levels of   
   >gradation from light to dark areas. Most of the HDR software   
   >applications allow a great deal of editing features, the goal being to   
   >output a photograph that better renders "reality."   
   >   
   >Brightness per se is not increased, the gradations of tone between the   
   >brightest and darkest areas is increased, dramatically. Since it is   
   >these gradations between light and dark that we interpret as volume, a   
   >photograph will appear to have more volume and depth (my understanding).   
   >   
   >I don't begin to understand the theory and technology behind this   
   >technique. But, I can *easily* see an improvement in the results.   
   >Software to generate and edit HDR photographs has become popular only in   
   >the last year, so its use by hobbyists is still in the very early stages.   
      
   Thanks a lot for the explanation, now I beleive I understand it   
   better.   
   The best thing with the digital camera is that it doesn't cost a   
   fortune to make errors anymore, when it's possible to make experiments   
   and explore it with unlimited amounts of pictures with instant   
   results. The only limit is the time..   
      
   Irene Andersson   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)