Archived posting to the Leica Users Group, 1999/07/27
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]> > "Noel H. Charchuk" wrote: > > > Alex asked: > > > What does the 'f' in f-stop stand for? > > ><snip> > > > According to the Ilford Manual of Photography, relative aperture is the > > > relationship of the focal length of the lens divided by the diameter of > > > the effective aperture. N=f/d. "The numerical value of relative aperture > > > is usually prefixed by the letter f and an oblique stroke, eg f/8. The > > > letter f and the stroke serve as a reminder of the relation between > > > relative aperture, effective aperture and focal length. The relative > > > aperture of a lens is commonly referred to as its f-number" > > ><snip> > > > > In other words: you don't know! > > Mark :-) Rabiner > > WTH you talkin', man? I thought he done good! > > -- > Roger Was kidding. ":-)" Your discription was so precise their would be no question. Although later on in the thread I was reminded that F stood for focal length which I knew once but those brain cells are long gone. The most important and interesting thing about your description for me is the emphases on the slash "/" which as you state represents a "relationship." I imagine a T stop would not represent a relationship but a fixed diameter. I now understand this issue for the first time. The idea that F stood for Focal length never sunk in because it did not compute; length and width being not the same thing. It is the "/" that counts. Mark Rabiner