Am 01.08.2012 10:16, schrieb CRIS:

> In fact I have not explained very well;  in practice I want to know if povray
> faithfully reproduces the view of a real camera, but i think the answer is 'yes'
> because this is the main functionality of povray.

Actually, it's much more complicated than that.

What it /does/ faithfully reproduce is a pinhole camera (using the 
"perspective" camera), or a single-lens camera; but those distort 
objects seen at wide angles in an undesired fashion, so modern lens 
systems introduce additional "shaping" of the image countering this 
effect. OTOH this "shaping" has the unintended but inevitable side 
effect of bending straight lines, so camera manufacturers always need to 
make a trade-off there, and might make different choices for individual 
lens models.

So faithfully reproducing "a" real camera would require knowledge about 
that particular camera's exact properties, and a way to inform POV-Ray 
about it. POV-Ray doesn't go as far as that - it just offers /one/ 
individual choice of such trade-off (using the "ultra_wide_angle" camera).


That said, if you are only interested in the question of which objects 
are occluded by other objects, there is no difference between individual 
camera lens systems: As long as you ignore focal blur, they're all 
equivalent to using a classic pinhole camera and then applying some 
distortion filter to the resulting 2D image.

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