PanoTools:
Re: entrance pupil - nodal point
Dave 360texas.com 2004-Nov-12 21:50:23
As a matter of interest I also found this:
When viewing though the 8mm FC-E8 fisheye glass front at my pointed
up pencil is also pointed up.
When viewing through my Nikormat film SLR 50mm 1:1.4 lens, at my
pointed up pencil - the image is point down. meaning that the image
is inverted somewhere inside the lens, most likely at the iris
mechanism set at F16.
Interesting.
--- In #removed#, "Dave 360texas.com"
<#removed#> wrote:
>
> Ok..
> It only has an entrance and exit pupil through which ALL light
must
> pass before arriving at iris aperture physically located inside
the
> camera head at least 5 cm behind the rotation point.
>
> In this instance, this fisheye lens is acting only as a THICK
> complex LENS as the image is not inverted until it is inside the
> camera head.
>
> Image 3 This thick lens behaves according to your Higher Physics
> text book definition
>
> Image 3 http://360texas.com/images/lensangle.jpg
>
> Dave
>
> --- In #removed#, "Erik Krause" <#removed#>
> wrote:
> > On 12 Nov 2004 at 18:19, Dave 360texas.com wrote:
> >
> > > Image 2. The next picture is of a fisheye with no iris or
> aperature
> > > with groups of optics which channel the incoming light rays.
It
> > > appears that the image is inverted about mid center of the
lens.
> > >
> > > I suspect that the point where the image is inverted is a
nodal
> > > point.
> >
> > No. It is the point for the best location of the iris aperture.
In
> > this diagram you can see very good that there is no exact nodal
> > point. You find the nodal point for any viewing angle if you
> lengthen
> > the direction of the light rays outside the front lens to where
> they
> > cut the optical axis. It is easy to see that this point moves
with
> > the angle of view.
> >
> > best regards
> > --
> > Erik Krause
> > Ressources, not only for panorama creation:
> > http://www.erik-krause.de/
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