Ceramic Pinhole Cameras
Posted: Sat Sep 18, 2010 2:44 pm
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It is based on the ISO of the film, and the f-stop of the pinhole. The f-stops range from about f120 to f350. I can generate a chart that will give you an effective ISO for the f-stop that can be used with a light meter. For my 4x5 inch pinhole camera, the f-stop is about f225. With ISO 320 film, and looking it up in the chart, I know that I need to use an ISO of 12 with my light meter, and I use an f-stop of f45, since that is the smallest f-stop the meter can use. Other than that, it is just a matter of using the light meter to determine the number of seconds for the base exposure, and then I use a chart to determine the reciprocity effect exposure time.JohnSR wrote:Those were interesting. Was wondering how you determine the exposure time?