Hi, Greg, Thank you for the input. With your confirmation, I can be rest-assured that I don't have to worry about taking couple more under-exposed brackets for concentrated light sources, which also make the alignment and merging process harder.
I am actually on Windows with HDR Shop. Really hope that there is a windows version of Photoshere such that we can use its flare reduction feature, which seems not available anywhere else. I have read comments in this mail list and other places about merging directly from RAW for accuracy. In my experience, it brought me more troubles than generating visually obviously better IBL results. At the end, I am not after pure scientific accuracy. Hence, I just use commercial applications like Adobe Lightroom to convert RAW brackets to intermediate TIFFs, with minimum color or luminance related adjustments applied, for HDR merging. I have had this "capturing concentrated light sources" question for quite a while and did came across Stumpfel's paper/thesis and corresponding section in your book (the section written by Debevec). My main interest is image-based lighting for visual effects type of works. As I came across a SIGGRAPH course note by Ben Snow's (ILM) and read about their on-set lightning acquisition workflow: Canon 1DS + Sigma 8mm fisheye + 0.6 ND filter for exterior shot. If compared to Stumpfel's 3.0 filter with varied aperture sizes controlled by laptop to shorten the exposure time for over-exposed brackets, I wonder if the former is simply capturing the environment map as a high-ish dynamic range image (instead of fully recover light sources illumination) and relying on visual-based indirect approach (via 18% gray sphere photograph) to calibrate the light source's contribution. But then what's the point of using that 0.6 ND filter if the indirect calibration of light source's contribution will be conducted anyway? Why not just capture an environment map without the filter and manipulate the pixel values of the light source in floating point space in post until whatever their calibration approach tells them that the illumination of the light source is properly represented? best, Jason _______________________________________________ HDRI mailing list [email protected] http://www.radiance-online.org/mailman/listinfo/hdri
