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Mailinglist:PanoTools
Sender:Dave 360texas.com
Date/Time:2004-Nov-11 01:55:06
Subject:Re: entrance pupil - nodal point and Entrance Pupil location

Thread:


PanoTools: Re: entrance pupil - nodal point and Entrance Pupil location Dave 360texas.com 2004-Nov-11 01:55:06

My next question is what is the definition of "Nodal Point" and 
definition of "forward lens Entrance Pupil location" ?  After 
learning each definition, then we can compare the physical locations.

Please work with me on these issues.

--- In #removed#, "Dave 360texas.com" 
<#removed#> wrote:
> 
> BTW.: 
> Quote "There is not only one aperture inside each lens. There are
> several designed to minimize stray light. Any of them could be the
> one limiting the diameter of the pencil of rays if you don't stop
> down. Would this mean that the "no parallaxe point" moves if I stop
> down?" /Quote
> 
> I agree there is only 1 aperature device inside each lens.  
Because 
> it it a mechanical device that permits the camera owner to dial in 
> the F-Numbered like F-11, 16, 8 etc.  Dialing in the F-stop number 
> allows the depth of field to be changed.  Hence the Circle of 
> Confusion factor to come into play.
> 
> Dave @360Texas.com
> 
> 
> --- In #removed#, "Erik Krause" <#removed#> 
> wrote:
> > On 10 Nov 2004 at 22:52, John Houghton wrote:
> > 
> > > > On 10 Nov 2004 at 8:59, John Houghton wrote:
> > > > Sorry, but from optical geometry this can not be true. You 
> don't 
> > > > change refraction by putting an aperture somewhere, hence 
you 
> can  not 
> > > > modify the location of nodal point with this technique. 
> > > 
> > > I did say that this did not change the position of the nodal 
> point.  
> > > It is nevertheless the case that if you experimentally 
determine 
> > > the "no parallax" point, it corresponds to the position of the 
> > > aperture, not the nodal point.  Try it yourself.
> > 
> > I'll do it, but first off all please tell me the exact settings 
> you 
> > used. And please could you explain the theory why the "no 
> parallaxe" 
> > point should corresponds to the position of the aperture? This 
is 
> > contradictory to all I learned about geometrical optics and what 
> > proved to be true all the time...
> > 
> > BTW.: There is not only one aperture inside each lens. There are 
> > several designed to minimize stray light. Any of them could be 
the 
> > one limiting the diameter of the pencil of rays if you don't 
stop 
> > down. Would this mean that the "no parallaxe point" moves if I 
> stop 
> > down?
> > 
> > best regards
> > -- 
> > Erik Krause
> > Ressources, not only for panorama creation:
> > http://www.erik-krause.de/





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