for constructing a positive lens use a sphere-sphere intersection, for a
negative one a difference of a cylinder with two spheres. To calculate the
radii of the lens you need the lens-makers formula (could simply be made
into a macro)
P=(nl-n0)((1/R1)-(1/R2))
P=n0/f

P=power of the lens
nl= ior of the lens (put this one also in your interior)
n0= ior of air (~1)
R1, R2= radius of the lens-surface
f=focal distance of the lens

for construction of optical systems you need Newtons and/or Gauss' lens
equation.
For looking through a system POV-Ray is ok, for making the path of light
visible you need Nathans' uv-patch. POV lenses are perfect, no abberations
or dispersion. I constructed a fresnel-lens that works fine, the macro is at
twyst's macroscope.

Ken posted a URL with a lot of optics info a few days ago. ( I lost the url
already, Ken how do you maintain  400+ bookmarks? A utility or just your
neural network?)


ingo
--
Met dank aan de muze met het glazen oog.



Rune S. Johansen heeft geschreven in bericht <37124c8f.0@news.povray.org>...
>Is there any tutorials on how to make lenses that works in POV-Ray?
>I mean how to use lens shapes with ior cleverly.
>F.x., is it possible to make two lenses that gives different zoom
>when back and forth away?
>
>Thanks,
>
>Rune S. Johansen
>http://hjem.get2net.dk/rsj

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