POV-Ray : Newsgroups : povray.general : Modelling vignetting in the 'camera' Server Time
5 Nov 2024 18:22:40 EST (-0500)
  Modelling vignetting in the 'camera' (Message 1 to 2 of 2)  
From: Don Barron
Subject: Modelling vignetting in the 'camera'
Date: 27 Jan 2003 17:00:19
Message: <web.3e35aba5659c4c6c51153da0@news.povray.org>
Does anyone have any suggestions as to how one might simulate the vignetting
in early camera lenses. So for example how to control the brightness of the
image in terms of its angular distance from the look_at according to cos(
theta)


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From: Charles
Subject: Re: Modelling vignetting in the 'camera'
Date: 27 Jan 2003 20:01:04
Message: <3E35D76B.3FAA68D3@enter.net>
Don Barron wrote:
> 
> Does anyone have any suggestions as to how one might simulate the vignetting
> in early camera lenses. So for example how to control the brightness of the
> image in terms of its angular distance from the look_at according to cos(
> theta)

Not angular brightness, exactly, but if I understand the artistic
effect you're shooting for, try this instead:

Sample may need adaptation for your particular scene, but it will 
do to decide if it's what you need. Animation of scale could
be made into a wipe effect, the color of the border is variable
at need, and different patterns will allow for different border
shapes...
-----------------------------------------------------------------
#include "transforms.inc" //needed for Reorient_Trans

/*camera location and look_at are declared because the effect
  depends on them later... */
#declare CamPos=<0,10,-20>;
#declare CamTarget=<0,2,0>;
#declare CamAxisDiff=CamTarget-CamPos;

camera {
    location CamPos
    look_at CamTarget
}

plane { //this is the filter...
    y, -0.9*vlength(CamPos)
    pigment { 
        wood
        color_map {
        [ 0 rgbt<0,0,0,1>  ] 
        [ .25 rgbt<0,0,0,1> ] 
        [ 1 rgbt<0,0,0,0>  ]
        }
        rotate<90,0,0>
        scale 2.25        
   }
   no_shadow
   Reorient_Trans(y, CamAxisDiff) 
   translate CamTarget
}

//a generic scene to vignette...
light_source { <100,100,-100>  rgb <1,1,1> }
plane { y, 0  pigment {  checker color rgb .5 color rgb .75 } }
sphere {  CamTarget, 2  pigment { rgb<0,0,1> }  finish  { phong .75 } }


-- 
@C[$F];
The Silver Tome ::  http://www.silvertome.com 
"You may sing to my cat if you like..."


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