I posted a message in p.o-t about my idea for a holographic camera. i'd like to
test the principle using Pov if possible. What I'd need to know is if photon's
work realistically enough to test the functionality of lenses. I,m not so sure
simple raytracing would. And then there is the question of the exact shape of a
lens and the location of it's focal point and how to model a lens in Pov.  If
it's just an intersection of 2 sphere's or a squashed sphere, it would be quite
easy, but I'm not so sure it's that simple.

Nekar
--
#local N=<-20,40,100>;#local K=<20,-40,100>;#local R=seed(0);blob{#while((K-N).
x>0)#local X=N;#local N=N+<rand(R),rand(R),1>/3;#local N=(vlength(N-K)<vlength(
X-K)?N:2*X-N);sphere{<N.y,-N.x,N.z>,1,1 scale .02}sphere{N,1,1 scale.02}sphere{
<-N.x-40,N.y,N.z>1,1 scale.01}sphere{<N.x+40,-N.y,N.z>1,1 scale.01 }#end
pigment{rgbt 1}interior{media{emission <2,4,5>*5}}hollow}// Nekar Xenos

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in news:3affb136@news.povray.org Nekar Xenos wrote:

> What I'd need to know is if photon's work realistically enough to 
> test the functionality of lenses.

Works quite good. Did a few simple things like making a 'paralell' beam 
and a slide projector.

> And then there is the question
> of the exact shape of a lens and the location of it's focal point
> and how to model a lens in Pov.

Unless you want to use a-spherical lenses it's mostly simple 
sphere-sphere difference and intersection and sphere-box difference. 
You'll need to know the lens-makers formula to find the appropriate 
radii and ior for the lens.


Ingo

-- 
Photography: http://members.home.nl/ingoogni/
Pov-Ray    : http://members.home.nl/seed7/

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Thanks

> Unless you want to use a-spherical lenses it's mostly simple
> sphere-sphere difference and intersection and sphere-box difference.
> You'll need to know the lens-makers formula to find the appropriate
> radii and ior for the lens.

Does anybody know where I can get the lens makers info?

Thanks

Nekar

--
#local N=<-20,40,100>;#local K=<20,-40,100>;#local R=seed(0);blob{#while((K-N).
x>0)#local X=N;#local N=N+<rand(R),rand(R),1>/3;#local N=(vlength(N-K)<vlength(
X-K)?N:2*X-N);sphere{<N.y,-N.x,N.z>,1,1 scale .02}sphere{N,1,1 scale.02}sphere{
<-N.x-40,N.y,N.z>1,1 scale.01}sphere{<N.x+40,-N.y,N.z>1,1 scale.01 }#end
pigment{rgbt 1}interior{media{emission <2,4,5>*5}}hollow}// Nekar Xenos

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in news:3affbf92@news.povray.org Nekar Xenos wrote:

> Does anybody know where I can get the lens makers info?
> 
Sorry, should have added it:

P = n0/f = (ng-n0)(1/R1 - 1/R2)

P  is power of the lens in m^-1
n0 is refractive index of air, use 1.00
f  is the focal length of the lens.
ng is refractive index of the lens.
R1, R2 are the radii of the lens.

for more info:

http://www.google.com/search?q=lens+makers+formula&btnG=Google+Search

Ingo

-- 
Photography: http://members.home.nl/ingoogni/
Pov-Ray    : http://members.home.nl/seed7/

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Thanks :)

Nekar

--
#local N=<-20,40,100>;#local K=<20,-40,100>;#local R=seed(0);blob{#while((K-N).
x>0)#local X=N;#local N=N+<rand(R),rand(R),1>/3;#local N=(vlength(N-K)<vlength(
X-K)?N:2*X-N);sphere{<N.y,-N.x,N.z>,1,1 scale .02}sphere{N,1,1 scale.02}sphere{
<-N.x-40,N.y,N.z>1,1 scale.01}sphere{<N.x+40,-N.y,N.z>1,1 scale.01 }#end
pigment{rgbt 1}interior{media{emission <2,4,5>*5}}hollow}// Nekar Xenos

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Could I have the code for the slide projector? I've figured that just looking
through a lens isn't necessarily going to simulate the image a real camera would
make, just the same way as you wouldn't see the big image a slide projector
shows by standing in front of the screen and looking at the projectors lens. :)

I remember something from school that this requires a concave lens but I'm still
not sure why and how you simulated this with Pov. Does it have something to do
with caustics?

--
/* Nekar Xenos */#local N=<-20,40,100>;#local K=<20,-40,100>;#local R=seed(0);
blob{#while((K-N).x>0)#local X=N;#local N=N+<rand(R),rand(R),1>/3;#local N=(
vlength(N-K)<vlength(X-K)?N:2*X-N);sphere{<N.y,-N.x,N.z>,1,1 scale .02}sphere{N
,1,1 scale.02}sphere{<-N.x-40,N.y,N.z>1,1 scale.01}sphere{<N.x+40,-N.y,N.z>1,1
scale.01 }#end pigment{rgbt 1}interior{media{emission <2,4,5>*5}}hollow}

"ingo" <ing### [at] homenl> wrote in message
news:Xns### [at] povrayorg...
> in news:3affb136@news.povray.org Nekar Xenos wrote:
>
> > What I'd need to know is if photon's work realistically enough to
> > test the functionality of lenses.
>
> Works quite good. Did a few simple things like making a 'paralell' beam
> and a slide projector.
>
> > And then there is the question
> > of the exact shape of a lens and the location of it's focal point
> > and how to model a lens in Pov.
>
> Unless you want to use a-spherical lenses it's mostly simple
> sphere-sphere difference and intersection and sphere-box difference.
> You'll need to know the lens-makers formula to find the appropriate
> radii and ior for the lens.
>
>
> Ingo
>
> --
> Photography: http://members.home.nl/ingoogni/
> Pov-Ray    : http://members.home.nl/seed7/

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in news:3b0a1144@news.povray.org Nekar Xenos wrote:

> Could I have the code for the slide projector?

Posted in p.t.s-f
Message-ID: <Xns### [at] povrayorg>

Ingo

-- 
Photography: http://members.home.nl/ingoogni/
Pov-Ray    : http://members.home.nl/seed7/

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Thanks!  =)

--
/* Nekar Xenos */#local N=<-20,40,100>;#local K=<20,-40,100>;#local R=seed(0);
blob{#while((K-N).x>0)#local X=N;#local N=N+<rand(R),rand(R),1>/3;#local N=(
vlength(N-K)<vlength(X-K)?N:2*X-N);sphere{<N.y,-N.x,N.z>,1,1 scale .02}sphere{N
,1,1 scale.02}sphere{<-N.x-40,N.y,N.z>1,1 scale.01}sphere{<N.x+40,-N.y,N.z>1,1
scale.01 }#end pigment{rgbt 1}interior{media{emission <2,4,5>*5}}hollow}
"ingo" <ing### [at] homenl> wrote in message
news:Xns### [at] povrayorg...
> in news:3b0a1144@news.povray.org Nekar Xenos wrote:
>
> > Could I have the code for the slide projector?
>
> Posted in p.t.s-f
> Message-ID: <Xns### [at] povrayorg>
>
> Ingo
>
> --
> Photography: http://members.home.nl/ingoogni/
> Pov-Ray    : http://members.home.nl/seed7/

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Dear Nekar,

I'm a professional lens designer ( and keen  even obsessive MegaPov user).
I  have done a lot of work with Nathan Kopp's photon mapping and used it to
simulate real lenses to assess stray light.    It really does trace real
rays and one can form images with them - limited only by the lens
aberrations.  It is quite simple to model lenses by the technique you
describe.  I have written a whole array of includes to model the four lens
shapes - and catalogues of materials.   I've used isosurfaces to represent
aspheric lenses.   But you'll need a very fast PC - a typical raytrace
through a 5 element lens may take 30mins ( on my P3/400MHz ).  I'm facing up
to acquiring the fastest twin Athlon PC.  Typically I trace rays at 128
positions in the image field - this is a long job..

If you're really serious about this requirement I could send you some worked
examples.

So, what's this idea for a holographic camera?
If you want to e-mail me use my office address which is

don### [at] ukthalesgroupcom

Yours,

Don Barron




"Nekar Xenos" <j-p### [at] citywalkcoza> wrote in message
news:3affb136@news.povray.org...
> I posted a message in p.o-t about my idea for a holographic camera. i'd
like to
> test the principle using Pov if possible. What I'd need to know is if
photon's
> work realistically enough to test the functionality of lenses. I,m not so
sure
> simple raytracing would. And then there is the question of the exact shape
of a
> lens and the location of it's focal point and how to model a lens in Pov.
If
> it's just an intersection of 2 sphere's or a squashed sphere, it would be
quite
> easy, but I'm not so sure it's that simple.
>
> Nekar
> --
> #local N=<-20,40,100>;#local K=<20,-40,100>;#local
R=seed(0);blob{#while((K-N).
> x>0)#local X=N;#local N=N+<rand(R),rand(R),1>/3;#local
N=(vlength(N-K)<vlength(
> X-K)?N:2*X-N);sphere{<N.y,-N.x,N.z>,1,1 scale .02}sphere{N,1,1
scale.02}sphere{
> <-N.x-40,N.y,N.z>1,1 scale.01}sphere{<N.x+40,-N.y,N.z>1,1 scale.01 }#end
> pigment{rgbt 1}interior{media{emission <2,4,5>*5}}hollow}// Nekar Xenos
>
>

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