Well if there are infinite settings going from 32 bit to an final 8 bit image, where is the benefit of calling the final image "HDR"? The common use of hdr in recent photography trends, is that your final output is a capture that looks more real to your eye, and properly done has a mildly surreal look, as the photo has multiple exposures that capture the lighting just so. The magic happens when you tonemap the image in the appropriate software, and the highlighted areas are combined into a final image. Most good photography sites say "true HDR photography" cannot be culled from a single set of data or image. Yes an .exr file- which I do understand to be an HDRI format, contains the infinite lighting possibilities, but to really make the image POP takes multiple captures, with contrasting areas of highlights and reflections. Once these are combined the true nature (as implied by a photographer) is revealed in the final image. One single .exr file tonemapped in Photomatrix (in my experience) is no where near the result of multiple images or exposures. The same can be said from a photographers perspective. A RAW file contains infinite possibility's, and yes a decent HDR can be produced from a single file. To really achieve the desired effect though takes multiple exposures to get the lighting to pop at every level. In my camera I shoot bracketed RAWs that give me three RAW image files at different exposures. Some people take up to twenty. If I tonemap one RAW file, I would never consider that a TRUE HDR photograph. I feel the same holds true for .exr. You can do it with one. But try it with three or better yet six! - Bill .
