copied and pasted from Mark's post: > d = 2fc*(m+1)/m^2 > > where d=dof, f = f stop, c = circle of confusion size, and m = magnification.
Now, if anyone can see a value for focal length in the above formula, he needs to talk to a good shrink about his over active imagination. My reply was change "f" to "a" (aperture-diameter) to correct the formula. (Though in the copy I have f = aperture, which is the same as using a). Us people who know everything are getting real tired of you people who think you know everything <GRIN>. Ciao, Graywolf http://pages.prodigy.net/graywolfphoto ----- Original Message ----- From: "mishka" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Thursday, July 24, 2003 7:08 PM Subject: Re: Shallow DOF with 6X7 lenses (was: 6x7 lenses - Brotherhood comments solicited) > T Rittenhouse wrote: > > Change f (f-stop) to a (aperture diameter) and it works fine. > > if you look at the formula, as Mark and I wrote it, the > DOF has dimensions of length. if you change f-stop to the actual > diameter, the dimension will become length^2, which cannot be. > > best, > Mishka >
