clark_savage_jr. Posted May 25, 2001 Share Posted May 25, 2001 I have several old lenses mounted in Kodak ball bearing shutters thatdate from around 1916. The callibrations are in U.S. stops. How dothese relate to modern f/stops? Link to comment Share on other sites More sharing options...
william_hahn1 Posted May 25, 2001 Share Posted May 25, 2001 See this thread (which I found by typeing "US fstops" into a google search): <p> http://hv.greenspun.com/bboard/q-and-a-fetch-msg.tcl?msg_id=000P49 Link to comment Share on other sites More sharing options...
john_henderson1 Posted May 25, 2001 Share Posted May 25, 2001 Actually, according to Kingslake (<em>History of the Photographic Lens</em>), U.S. stands for "Uniform Scale" and is N*N/16, where N is the f-number. <p> The beauty of this system is that doubling the U.S. number halves the exposure, instead of the f-number system in which multiplying the f-number by the square root of two halves the exposure. Link to comment Share on other sites More sharing options...
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