Let me get some of my confusion straightened out, before I go into overload! <g>
Some sources I've read and some posts I've read here quote line pairs per mm, while others speak of lines per mm as resolution values. I have observed some posters using one value when they meant the other, and I doubt they intend to. I think we ought to stick with one system of measurement, for clarity, and I'm intending to start with me! I assume a resolution test target would have varying values of line widths and spacing, for evaluation purposes, but for illustration, can I assume a "line pair" is defined as two black lines of equal width separated by white or grey space the same width as the lines? For instance, if I were to specify a .01mm line width, a line pair would be two .01mm black lines, with a white space of .01mm width separating them. The "pair" would then have an .03mm overall width. In attempting to equate this to lines per mm values, I will assume the width of one line, plus a space of equal width as being a 'unit' and however many units fit into a 1.0 mm space is the "lines per mm" value. That being so, given the same line widths in each case, for the same resolution capability one would have double the "lines per mm" value than "line pairs per mm." Agreed? In other words, a lens with a resolving power of 25 line pairs per mm can also be said to be able to resolve 50 lines per mm. Same actual resolution capability, different units. Is one of them any industry-accepted "standard?" keith whaley [EMAIL PROTECTED] wrote: > > Even with a perfect lens, there's no way you can get close to 100 lp/mm at aperture > 22. > > DagT > > > > > Fra: "J. C. O'Connell" <[EMAIL PROTECTED]> > > NOT TRUE, > > > > Even the best 35mm film is only about 200 lp/mm. > > > > Even using an excellent lens of 200 lp/mm results > > in a film/lens combination of only 100 lp/mm. > > > > The film DOES affect the result, even the best films.... > > JCO
