Dear Jan-Peter, I do know of this solution. I actually built a very similar one (with a better light source) couple of years ago, and nearly all generic camera profiles for RPP are calculated using it. However, for lens profiling it is not a good one, adding too much hassle to measure SPD for each filter and combining those. A ~$2000 monochromator might be an easier solution than, as now we are not limited with sensor sensitivity to 9mkW radiation power ;) I'm actually looking for a more straightforward solution, like a halogen lamp and a decent spectrophotometer. Paying ~$10,000 for a spectroradiometer to support a free raw converter seems a little excessive ;) On May 27, 2011, at 9:59 AM, Jan-Peter Homann wrote: > Hello Iliah, > > I don´t know how if you are doing professional work in this area, but may be > camSPECS from Image Engineering, could deliver some very interesting inside > views for your work. > > ... from the vendor... > camSPECS is a fast and affordable solution to measure the spectral response > of a digital camera system (access to RAW image files required). It contains > the hardware and software tools, which are necessary to perform the > measurement. > > The light source is a modified slide projector with a stabilized power > supply, a special filtering of the light source and a customized optical > system. A set of 39 narrow-band interference filters is used to generate the > narrow-band light. The slide transportation system of the projector is used > to move the filters one after another in front of the lamp. Beside the > interference filters are neutral density filters, which are used as a > brightness reference to correct for exposure variations. Exposure data is > used to correct for different exposure levels. So it is possible to perform > the measurement even with the camera set to automatic exposure control. > .... from the vendor .... > > http://www.image-engineering.de/index.php?option=com_content&view=article&id=73&Itemid=63 > > Best regards > Jan-Peter > > Am 26.05.11 04:48, schrieb Iliah Borg: >> Dear Listmembers, >> >> For raw conversion, I need to decide if I'm going to use lens / filters >> (polarizing filters are my primary concern) correction matrices over sensor >> "profiles" or not. To make up my mind I need to take measurements of >> spectral transmissions of different lenses and filters. Instrumentation I >> have is: i1Pro and Spectrolino/SpectroscanT. I'm not sure I can use the lamp >> in SpectroscanT (if you know it is possible please advise so), so I started >> with i1Pro. >> >> From reading argyll/spotread documentation it seems that I can use emission >> mode, measuring separately the light source as a backlit and the light from >> the same source passing through the lens; than calculate the transmission >> dividing the pairs of numbers for each wavelength. As far as I understand no >> ambient light attachment is needed in this case. >> >> Another option would be to use -t flag, however only DTP41T and SpectroScanT >> are listed for this flag (with the option to use Spectroscan with a separate >> backlit light). Does this mode works for i1Pro too? An attempt to run it >> with i1Pro caused no error messages, however the results are different from >> those obtained through spotread with -e flag (might be of course because in >> a quick experiment the lens was not placed to the same position). >> >> Any comments and advice would be highly appreciated. >> >> On a side note, running spotread from Argyll CMS 1.3.3 with -p flag >> /projector measurement mode/ (OS X 10.6.7) returned "unsupported for my >> i1Pro. >> >> -- >> Iliah Borg >> ib@xxxxxxxxxxx >> >> >> >> >> > > > -- > ---------- Please note the new adress -------------- > > homann colormanagement --------- fon +49 30 611 075 18 > Jan-Peter Homann ------------ mobile +49 171 54 70 358 > Cotheniusstr. 3 -------- http://www.colormanagement.de > 10407 Berlin -------- mailto:homann@xxxxxxxxxxxxxxxxxx > > > -- Iliah Borg ib@xxxxxxxxxxx