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
>
>
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---------------------------------------------------------
Gordon J. Holtslander Dept. of Biology
holtsg@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
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Received on Mon Mar 4 23:02:12 2002
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