Mike Horvath <mik### [at] gmailcom> wrote:
> I'm trying to achieve this effect:
>
> https://en.wikipedia.org/wiki/Miniature_faking
>
> Of course, in POV-Ray you don't need to fake it since you can create
> cameras of any scale and dimensions.
>
> But I'm not happy with the visual results. It simply does not look as
> nice as the photos in the Wikipedia article.
>

The Wikipedia photo was, I believe, created with a post-processing blur effect
on an already-taken 2D photo. The article says,
"A common technique for making an image of a full-size scene resemble an image
of a miniature model is to have the image progressively blurred from the center
to the top or bottom" (of the image.) In other words, it's a simple 'linear'
effect-- the same amount of blurring on both sides of that centerline.

For a REAL camera lens (one that can show obvious depth-of-field effects, like a
good DSLR lens), the relative amount of blur on either side of the 'in-focus'
plane may not be linear-- that is, producing more blurring over a given distance
between camera and in-focus object than between that in-focus object and an
*equal* distance behind it. For a real lens, there is a settable focus distance
called the 'hyperfocal distance', that tries to keep as much of the scene as
possible in focus. My understanding of that (and from old camera tests of my
own) is that such a distance is not 'halfway between zero distance and infinity'
but something closer to the camera. In other words, the final blurring across
the depth of the scene is not a simple 'linear' one in relation to the in-focus
plane.

I actually haven't tried setting up such an experiment in POV-Ray, to see
whether or not its focal_blur effect is 'linear' the way I describe it. It has
been on my to-do list for quite awhile ;-) The result probably has some bearing
on your question.

Post a reply to this message