in news:web.4243177b95205ba1a0c272b50@news.povray.org gonzo wrote:

>> With the camera, we can change the distance of focale? Is this the
>> angle into the focale and the objet?
> 
> Povray doesn't have focal length as such, but you can move the camera
> further from, or nearer to the object and then play with the angle to
> achieve the same field of view.
> 

Have to correct you here a bit Gonzo, changing the camera angle is the 
equivalent to changing the "focal length" in real photography. Even
this is not completely true, POV-Ray's perspective camera is a pin-hole
camera, so changing the angle in POV is like changing the distance
between the film plane and the pinhole.

Changing the camera angle has the same effects on the image as changing
the focal length with a camera, except for the depth of field, which is
infinite just as in a pinhole camera. One uses the angle to determine
the field of view and the distance to the object for the perspective
(further away, 'flatter' perspective, less 'distortion' near the
corners). 

The focal blur POV-Ray is set through a few parameters and does not 
depend on focal length or aperture.


Ingo

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