What do you call this sort of shareware and how would you find it on the internet? I did do some calculations manually and the exponent went down as the times went up. That is, for a metered time of 3 seconds, raising it to the 2.1 power gave you ten, which was what the chart said the adjusted time should be, but for four seconds the exponent was 1.95, for five seconds it was 1.85. I assumed it would keep going like that so I gave up.
--shannon ---------- >From: "G.Penate" <pen...@rogers.com> >To: <pinhole-discussion@p at ???????> >Subject: Re: [pinhole-discussion] HP5, Delta films and reciprocity >Date: Sat, Jul 20, 2002, 2:30 PM > > > ----- Original Message ----- > From: "Shannon Stoney" <shannonsto...@earthlink.net> > >> This is interesting, a variation on the formula I was given. Where did you >> get this formula? I wonder if such formulas exist for all films? > >> I have been using this formula successfully for about a month. It seems to >> give good times. I have no idea why this "works" mathematically. > > The formula you use is known as "Best Curve Fit", it works by finding a formula > whose curve fit best to all the points in a graphic of "metered vrs reciprocity > corrected values". In other word, you first find by experimentation as many > values as possible and then apply the "Best Curve Fit" method of choice (there > are many, BTW) to find a formula that matches them best. Once you have a > formula, you can inter and extrapolate to find any other corrections you want. > > There are shareware programs available that allow you to find the formulas w/o > having to do it manually and w/o having to like or to be good at math. > > Guillermo > > > > _______________________________________________ > 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/
