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From: jeh@ritcv.UUCP (Jim Heliotis)
Newsgroups: net.rec.photo
Subject: A Question: f-values vs. #Stops
Message-ID: <39@ritcv.UUCP>
Date: Tue, 30-Apr-85 12:29:31 EDT
Article-I.D.: ritcv.39
Posted: Tue Apr 30 12:29:31 1985
Date-Received: Wed, 1-May-85 06:41:25 EDT
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Organization: Rochester Institute of Technology, Rochester, NY
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What is the relationship between f-stops and stops?  I think I know what it is
in shutter speeds:

	delta(stops) = log2(old-speed / new-speed)

sort of like S/N ratios in bels.

Can anyone tell me the equivalent formula for f-stops?  A description of
exactly how they are measured would be nice, too.

				Jim Heliotis
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