Archived posting to the Leica Users Group, 2001/02/09
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]>> Also, the films of today are much better at resolving fine detail than the >> films of 30 years ago -- yet our perception of DOF has not changed much, >> which would run counter to your argument. >> > How does that counter my argument? > > Because you're making the claim that DOF is an objective property. If the > materials have changed, then DOF should have changed too. That does not counter my statements. It just means that no one has taken the initiative to re-evaluate it. In fact, as I have said before, noted experts in the field have stated it needs to be re-thought. But you conveniently ignore that. > Which means that people are in all likelihood misunderstanding what DOF DOF is a characterization of any optical system. Photography has adopted its own definition of it to mean what it wants it to mean, but outside of photography, it is characterized differently. I have designed quite a number of digital imaging systems, that have nothing to do with humans viewing prints at a particular distance. And, of course, these systems have DOF, and they are not subject to viewing a print at 1.5x the longest side of the print. I understand 'pohotographic' DOF as you are refering to it, but as I just said, there are MANY other DOFs. I believe that may be one of the reasons you are having trouble understanding my points. > No, I'm not going to push this into the subjective/objective philosophical > debate. That would be a cop out. But, if it doesn't require perception, > what measuring device would you use that is independent of magnification? Well, that IS your argument. ALL measurements have error, period. You need to understand that in order to understand what measurement is. > > That does not negate the ability to measure it, it only adds error to your >> measurement. I believe the 'area of confusion' will be negligible to the >> overall measurement that can be achieved. > OK, first off, you're going to have to define "area and confusion" and how > it relates to DOF. Do you mean the CoCs, or something else? Because I did not want to confuse the issue using COC for something that is not photography based. The 'area of confusion' I am using is technically called error when it applies to measuring. > If you want > to convince others that your understanding of something is correct, you need > to provide convincing arguments for it. You need to be able to present how > it relates to other known knowledge, what the implications are, and also > account for existing phenomena. Simply stating that you believe something > doesn't cut it. It also requires 1) the willingness for someone to understand it, and 2) their ability TO understand it. > I, personally, believe that there is no such thing as "area > of confusion" and that is has absolutely not relevance to this discussion > at all Because you don't understand measurement, and that all measurements have error. I am going to guess you do not have either an engineering or scientific background, and as such, this knowledge is not inherent in your skill set. It does not mean you can not learn it, but not being exposed to the background and the experience leaves this knowledge lacking. > -- but I'm willing to bet a rather large sum of money that my > belief is > not sufficient to convince you that I'm correct. Correct about what? What it appears to me you are doing is parroting the common photographic definition of DOF, which is completely irrelevent to my points. I really believe you don't understand why. >>> Which requires something to be viewed at a particular magnification and >>> physical distance from the eye. >>> >> No. It converges, whether YOU view it or not. > Second, the "convergence" which I assume you are referring to isn't actually > convergence. What it is is the effects of focus. Of course it is the effect of focus, that is what we are talking about. It's when you state such simplistic 'understandings' that are inherent (at least to me, and I would hope anyone that could follow and understand these things) in the discussion, makes me wonder if you really get what is being said. You have yet to explain anything to me that I didn't already understand. What word you you suggest that is clearer (in your opinion) the the effect that happens to the lines? This is insanely time consuming, and I really have better things to do. If you really want to understand my points, and you really don't already, perhaps we ought to do this in a forum that is more appropriate for this type of discussion, say with a white board, the next time you are in the Boston area? - -------------------------------------------------------------------- Mail2Web - Check your email from the web at http://www.mail2web.com/ .