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From: Tony[B]
Subject: focal_blur post_process request
Date: 16 Jun 2001 15:37:43
Message: <3b2bb587@news.povray.org>
Hi. I was wondering if for the next version of MegaPOV, someone could make
the post-processed focal blur more like the real focal blur. You know, where
you can specify a point in 3D space you want it to consider the center and
then blur out from there, not from the camera. Can it be done? Is it already
possible and I have to go hide my head in the sand out of embarrassment from
not having seen it before? Thanks in advance.

--
Anthony Bennett


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From: Daniel Lin
Subject: Re: focal_blur post_process request
Date: 16 Jun 2001 18:20:57
Message: <3b2bdbc9@news.povray.org>
Just set focal_point to be whatever you want, like:

camera
{
    //blah

    aperture whatever
    blur_samples whatever
    confidence whatever
    variance whatever

    focal_point wherever //This is where it's focused at
}

(P.S. To people who know much more than me: is this right?)
(P.S.2: is there a mathematical relation between the aperture and the
f-stops on a camera?)

--
Me (Daniel Lin (dli### [at] yahoocom))


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From: Tony[B]
Subject: Re: focal_blur post_process request
Date: 16 Jun 2001 19:09:53
Message: <3b2be741@news.povray.org>
Daniel, thank you for your suggestion, but I'm afraid you misunderstood. For
regular POV, there is a slow, slow version that works as you described. For
MegaPOV, this can be done after rendering, in a post processing pass, but
there is no such thing as a focal_point. It goes from the camera outwards.
I'm asking for the post processed version to have this "focal_point"
feature, like the regular POV. Understand now?


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From: Daniel Lin
Subject: Re: focal_blur post_process request
Date: 16 Jun 2001 20:03:25
Message: <3b2bf3cd@news.povray.org>
Yep.  Oooh, then I have no idea what the answer is.  I'd like to know, too,
then.

BTW, does anybody know what relation (if any) there is between the apeture
setting and the actual f-stops on cameras?

--
Me (Daniel Lin (dli### [at] yahoocom))


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From: Oldstench
Subject: Re: focal_blur post_process request
Date: 17 Jun 2001 02:31:06
Message: <o3uoitcmsh7sea44m5fr0ci11mq9bq26hh@4ax.com>
"Tony[B]" <ben### [at] catholicorg> wrote:

>Hi. I was wondering if for the next version of MegaPOV, someone could make
>the post-processed focal blur more like the real focal blur. You know, where
>you can specify a point in 3D space you want it to consider the center and
>then blur out from there, not from the camera. Can it be done? Is it already
>possible and I have to go hide my head in the sand out of embarrassment from
>not having seen it before? Thanks in advance.

I honestly do not think that is possible, as post-processing happens to the
2d bitmap, not the actual scene file.
Oldstench................


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From: Warp
Subject: Re: focal_blur post_process request
Date: 17 Jun 2001 09:49:51
Message: <3b2cb57f@news.povray.org>
Tony[B] <ben### [at] catholicorg> wrote:
: For
: regular POV, there is a slow, slow version that works as you described.

  It's not that slow if you know how to use it. And it's a lot more accurate
than the post-process focal blur.

-- 
#macro N(D,I)#if(I<6)cylinder{M()#local D[I]=div(D[I],104);M().5,2pigment{
rgb M()}}N(D,(D[I]>99?I:I+1))#end#end#macro M()<mod(D[I],13)-6,mod(div(D[I
],13),8)-3,10>#end blob{N(array[6]{11117333955,
7382340,3358,3900569407,970,4254934330},0)}//                     - Warp -


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From: Tony[B]
Subject: Re: focal_blur post_process request
Date: 17 Jun 2001 10:47:24
Message: <3b2cc2fc@news.povray.org>
post_process has access to depth information.


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From: Tony[B]
Subject: Re: focal_blur post_process request
Date: 17 Jun 2001 10:48:07
Message: <3b2cc327@news.povray.org>
>   It's not that slow if you know how to use it. And it's a lot more
accurate
> than the post-process focal blur.

Alright. Tell me how to make it silky-smooth and still be not-so-slow.


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From: Warp
Subject: Re: focal_blur post_process request
Date: 17 Jun 2001 10:50:33
Message: <3b2cc3b8@news.povray.org>
Tony[B] <ben### [at] catholicorg> wrote:
: Alright. Tell me how to make it silky-smooth and still be not-so-slow.

  Set variance to 0 and choose a proper blur_samples.

-- 
#macro N(D,I)#if(I<6)cylinder{M()#local D[I]=div(D[I],104);M().5,2pigment{
rgb M()}}N(D,(D[I]>99?I:I+1))#end#end#macro M()<mod(D[I],13)-6,mod(div(D[I
],13),8)-3,10>#end blob{N(array[6]{11117333955,
7382340,3358,3900569407,970,4254934330},0)}//                     - Warp -


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From: Francois Dispot
Subject: Re: focal_blur post_process request
Date: 17 Jun 2001 12:48:07
Message: <3B2CDF43.E4D6BE9E@club-internet.fr>
Daniel Lin wrote:
> 
> Yep.  Oooh, then I have no idea what the answer is.  I'd like to know, too,
> then.
> 
> BTW, does anybody know what relation (if any) there is between the apeture
> setting and the actual f-stops on cameras?

Since the following macro works:

http://www.wozzeck.net/images/DoF.html

it seems that aperture has the "right" value... I mean that f-stops are
actually focal-length-divided-by... values. Eg. your nice 300mm f/2.8
has an "aperture" of 107 mm. The problem is to determine the "focal
length" of your camera, which is certainly not the one you get in 24x36
mm. See the macro page and source for more details.
-- 

      __  __ __  __  _
|  | /  \  /  / |_  /  |/
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