Hi Rob et al, one thing I could imagine to avoid setups with mounting internal filters (or, even worse, combining filter wheels and fisheye lenses ...) during the somewhat time-critical process of taking an exposure series... Did anyone try yet to use a short-pass filter at 350nm assuming a smaller direct/indirect ratio at short wavelengths, trying to apply models os spectral angular sky distributions to calculate back luminances? Or is this just a silly idea introducing too many uncertainties to remove a basic mechanical problem...?
Cheers, Lars. -- Dipl.-Ing. Architect Lars O. Grobe On Jan 26, 2011, at 0:50, "Guglielmetti, Robert" <[email protected]> wrote: > > On 1/25/11 4:33 PM, "Lars O. Grobe" <[email protected]> wrote: > >> Hi Claus! >> >> I am not optimistic about capturing sky and sun using a simple camera. >> Without worrying about hdr codes - unless you achieve an exposure quick >> enough to have a non-saturated sun image, the hdr code cannot do the >> magic and invent pixel values. You may try low-transmission filters, but >> that costs you the weaker sky luminances. So probably, hardware needed. > > > You could use filters to get the luminance peaks and extend the series by > re-shooting without the filter. Time and camera handling are definitely a > problem for getting an honest (and alignable) LDR series. Greg has a paper > on this someplace, I think. Can't find it right now... > > > Rob Guglielmetti IESNA, LEED AP > Commercial Buildings Research Group > National Renewable Energy Laboratory > 1617 Cole Blvd MS:RSF202 > Golden, CO 80401 > T. 303.275.4319 > F. 303.630.2055 > E. [email protected] > > > > > > > _______________________________________________ > HDRI mailing list > [email protected] > http://www.radiance-online.org/mailman/listinfo/hdri _______________________________________________ HDRI mailing list [email protected] http://www.radiance-online.org/mailman/listinfo/hdri
