Hi: It seems that rating the film at 1 ASA compensates for reciprocity. I'm not sure of the F-stop of the 12x18- its not my camera. We usually get a good estimate of the pinhole diamter using a loup and a fine ruler graduated in .5 mm From that we calculate the f-stop based on the focal length. We use a light-meter to get an exposure base.
It gets good negatives from exposures in the range of 5 min to an hour. Never had an exposure of less than 5 minutes with this film and LC-1 Gord On Mon, 4 Mar 2002, John Yeo wrote: > > > I use LC-1 and ortho film too. Its very good. However it is slow. An > ASA of 1. I've used a > > 12 X 18 camera. It ended up having an f stop in the range 0f 300. This > translates to an > > exposure of an hour on a bright sunny day for one picture. > > How does that work? For a sunny day exposure with ASA 1, you would have 1 > sec @ f/16. f/360 is 9 stops away from f/16, so your exposure should be > about 8.5 min... > > Or is it because of reciprocity failure that you are getting exposures of an > hour? > > John > > > _______________________________________________ > Post to the list as PLAIN TEXT only - no HTML > Pinhole-Discussion mailing list > Pinhole-Discussion@p at ??????? > unsubscribe or change your account at > http://www.???????/discussion/ > --------------------------------------------------------- Gordon J. Holtslander Dept. of Biology hol...@duke.usask.ca 112 Science Place http://duke.usask.ca/~holtsg University of Saskatchewan Tel (306) 966-4433 Saskatoon, Saskatchewan Fax (306) 966-4461 Canada S7N 5E2 ---------------------------------------------------------
