Has anybody tried building a physically accurate camera lens and
turning on photons to see what that does for a realistic lens flare?

-- 
Tim Cook
http://empyrean.scifi-fantasy.com
mirror: http://personal.lig.bellsouth.net/lig/z/9/z993126

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Timothy R. Cook wrote:
> Has anybody tried building a physically accurate camera lens and
> turning on photons to see what that does for a realistic lens flare?
> 

Wouldn't that require an insane number of photons, as well as a 
high-quality dispersion setting? I'm thinking this might be a great 
thing to try in 2006... ;P

-Xplo

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Timothy R. Cook wrote:

> Has anybody tried building a physically accurate camera lens and
> turning on photons to see what that does for a realistic lens flare?
> 

You can check it against OSLO which has DXF output, giving you identical 
geometry for your POV simulation. The demo may even have the optics you 
need for a camera zoom lens.

http://www.sinopt.com/software1/soft_hilites.htm

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Hey,

> Has anybody tried building a physically accurate camera lens and
> turning on photons to see what that does for a realistic lens flare?

Someone did this about two years ago I think (it was a long time ago,
anyway), except instead of photons (which may not have even been around at
the time), they just used a sphere with a really high ambient value as the
light source, and I think they gave a very slight coloured tint to the
lenses. The results were... OK, I guess. Nothing nearly as nice as you'd get
with a lensflare include like Chris Colefax's. If you do a seach back in
this group, you *might* find it, but it was years ago, and I couldn't tell
you who it was or what it was called...


John

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"Timothy R. Cook" <tim### [at] scifi-fantasycom> wrote in message
news:3d8bff77@news.povray.org...
> Has anybody tried building a physically accurate camera lens and
> turning on photons to see what that does for a realistic lens flare?

I seem to remember this being discussed somewhere, pov.advanced-users maybe?

jim

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John Mellerick wrote:
> Someone did this about two years ago I think (it was a long time ago,
> anyway), except instead of photons (which may not have even been around at
> the time), they just used a sphere with a really high ambient value as the
> light source, and I think they gave a very slight coloured tint to the
> lenses. The results were... OK, I guess.

That's why I was asking what happpened if you also used photons; I saw
the original post.

-- 
Tim Cook
http://empyrean.scifi-fantasy.com
mirror: http://personal.lig.bellsouth.net/lig/z/9/z993126

-----BEGIN GEEK CODE BLOCK-----
Version: 3.12
GFA dpu- s: a?-- C++(++++) U P? L E--- W++(+++)>$
N++ o? K- w(+) O? M-(--) V? PS+(+++) PE(--) Y(--)
PGP-(--) t* 5++>+++++ X+ R* tv+ b++(+++) DI
D++(---) G(++) e*>++ h+ !r--- !y--
------END GEEK CODE BLOCK------

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In article <3d8cced6$1@news.povray.org>,
 "Timothy R. Cook" <tim### [at] scifi-fantasycom> wrote:

> That's why I was asking what happpened if you also used photons; I saw
> the original post.

Nothing really, other than a slowdown from wasted computations. Photons 
just light up surfaces and media. A lens doesn't have a surface that is 
very diffusively reflective, and the camera can't "see" the photons. 
Lens flares are specular reflections of the light source, not caustics 
on the lenses.

I guess you could make every single object in the scene interact with 
photons, use reflection with a fine-grained normal on all diffusely 
reflecting objects to scatter the reflected photons, and put a screen 
with double-illuminate between the camera and the lenses. I don't know 
if this would work, if it does, it would require insane numbers of 
photons and wouldn't have any advantages.

-- 
Christopher James Huff <cja### [at] earthlinknet>
http://home.earthlink.net/~cjameshuff/
POV-Ray TAG: chr### [at] tagpovrayorg
http://tag.povray.org/

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> > Has anybody tried building a physically accurate camera lens and
> > turning on photons to see what that does for a realistic lens flare?
>
> Someone did this about two years ago I think (it was a long time ago,
> anyway), except instead of photons (which may not have even been around at
> the time), they just used a sphere with a really high ambient value as the
> light source, and I think they gave a very slight coloured tint to the
> lenses. The results were... OK, I guess. Nothing nearly as nice as you'd
get
> with a lensflare include like Chris Colefax's. If you do a seach back in
> this group, you *might* find it, but it was years ago, and I couldn't tell
> you who it was or what it was called...


Perhaps that was me, this a posting I did in Nov 2001
http://news.povray.org/povray.binaries.images/19888/
It used a real 35mm camera lens setup with fresnel reflection and an ambient
light source so it is pure specular reflection and doesn`t use photons.  I
think I did this during beta testing of 3.5, but I have retried the image
recently with the final release of 3.5 without success so there must`ve been
some change regarding fresnel reflection in the interim.

-tgq

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