On 2/13/2018 6:08 PM, Kenneth wrote:
> 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.
> 
> 
> 
> 


The amount of blurring using a real lens might equal `atan(distance from 
camera)`, adjusted so that the crisp zone intersects the focal point.

I should try to see if I get better results using Photoshop for the 
blurring instead of POV-Ray. But I have some tall objects in my scene, 
which will mess up the Photoshop technique.


Mike

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