Archived posting to the Leica Users Group, 1996/05/21
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]You wrote: > > > >On Mon, 20 May 1996, Wolfgang Sachse wrote: > >> >> > Edward Meyers wrote: >> > >> > > This LED illumination device could be a big help... >> <snip> ... >> ..and Bill Christenson followed: >> > >> > ... I understand John Sexton will make 7+ minute exposures ... >> >> Hi - >> >> How does he compensate for reciprocity failure? >> >> -- Wolfgang >> =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= >> Wolfgang Sachse Cornell University >> sachse@msc.cornell.edu http://www.msc.cornell.edu/~sachse >> =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= >> >In color there are other problems. With B&W, check the manufacturer's >info sheets. Or call the tech numbers. Ed Meyers> > I have made many exposures of 10 to 20 minutes with my view camera shooting interiors with color tungsten film. There is practically no reciprocity failure from my 20 years of experience using tungsten film. I usually add a 82C filtermwith strobes and room light to keep the film color neutral. The exposure is simply determined by taking a Polaroid first. I use 55 Polaroid 4x5 positive negative film and check the density on the negative. I then shoot the same exposure as a well exposed negative and shoot six sheets with the same exposure. I only have one processed by the lab and still have five sheets to make any necessary corrections in the processing. I am rarely off by more than +/- 1/2 stop. Hope this helps. Mel Weinstein Santa Monica, California photog3@ix.netcom.com