POV-Ray : Newsgroups : povray.general : Source and camera film characteristics adjustement Server Time
29 Jul 2024 18:20:19 EDT (-0400)
  Source and camera film characteristics adjustement (Message 1 to 3 of 3)  
From: CIAS
Subject: Source and camera film characteristics adjustement
Date: 18 Aug 2010 14:35:00
Message: <web.4c6c26c53242f23c5ad854f30@news.povray.org>
Hi,
I'm a newbee in POVRAY.
I have two questions, which are the same...
- is it possible to change the characteristics of the ligth by specifying a
temperature for blackbody spectrum ? because I use non conventionnal ligthning
- in other and, is it possible to specify a sensibility to the camera point of
view ? I mean is it possible a ASA sensibility and time exposure ?

My objective is to model and simulate experiences of high speed camera
observation. I must set the ligth : power, x,y,z place...

In fact, I want to know if it is possible to make QUANTITATIVE images with
POVRAY ? according to calibrate illuminants and optical density of the films.

Thank you

Christophe


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From: Alain
Subject: Re: Source and camera film characteristics adjustement
Date: 18 Aug 2010 15:27:16
Message: <4c6c3414@news.povray.org>

> Hi,
> I'm a newbee in POVRAY.
> I have two questions, which are the same...
> - is it possible to change the characteristics of the ligth by specifying a
> temperature for blackbody spectrum ? because I use non conventionnal ligthning
> - in other and, is it possible to specify a sensibility to the camera point of
> view ? I mean is it possible a ASA sensibility and time exposure ?
>
> My objective is to model and simulate experiences of high speed camera
> observation. I must set the ligth : power, x,y,z place...
>
> In fact, I want to know if it is possible to make QUANTITATIVE images with
> POVRAY ? according to calibrate illuminants and optical density of the films.
>
> Thank you
>
> Christophe
>
>
>

There is nothing preventing you from using lights that are any colour 
beside white, you only need to provide the rgb value you want. Even 
negative values are legal. Keep in mind that POV-Ray use a 0..1 scale, 1 
been 100%, but you are not limited to that range.

You can only set the RGB colour of the light. That mean that you can 
reproduce the /broad/ aspect of the light. The black body case been 
effectively the simplest, can be replicated quite easity.
What you can't do, is to reproduce the effect of a light source that 
have a non-continouus spectrum, especialy if the object(s) been 
illuminated also have non-continouus colour characteristics.

I can recoment lightsys. It's a collection of include files designed to 
reproduce as well as possible real world illumination. It allows you to 


For the sensibility and exposure time, you should output to some High 
Dynamic Range format. You can then adjust the exposure as you want with 
some external image processing application.
For that, you'll probably need to use the current version 3.7 beta, as I 
don't think that version 3.6 can handle such formats. The current beta 
is fully functionnal and quite stable, it's only limitation is been time 
limited to prevent corrected bugs from older versions from been 
uselessly reported.



Alain


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From: Mr
Subject: Re: Source and camera film characteristics adjustement
Date: 26 Aug 2010 04:35:02
Message: <web.4c762665ffed041460a600320@news.povray.org>
Alain <aze### [at] qwertyorg> wrote:

> The current beta
> is fully functionnal and quite stable, it's only limitation is been time
> limited to prevent corrected bugs from older versions from been
> uselessly reported.
>
>
>
> Alain


Ah! That's the Povray secret I had never realized that reason for the date limit
system it's excellent!

Back on topic, I hope you will be able to do what you want in Povray, but
however, if you haven't already, have a look at Luxrender. If you have found
pros and cons and can't decide between these two renderers, I hope you chose Pov
;-)


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