Re: Cardboarding

[P3D John Bercovitz <bercov@xxxxxxxxxx>]

> one thing many people don't notice is "cardboarding" happens in reality 
> too.  Take a pair of binoculars and look around a little.  The other day 
> my girlfriend was looking through some binoculars at a mountain and she 
> noticed that the boulders in between us and the mountain looked like 
> "cardboard cutouts" (her words not mine).

Now that's an interesting variation.  What you have here is a lot more
parallax than usual due to the magnification of the binoculars (and also 
due to the wider separation of the objectives if these are conventional 
binocs).  The problem here is that when the space is reconstructed, it
is more magnified in lateral directions than in depth.  See orthomag and/
or pepax in the bobcat technical directory.

In orthomag, the right view would be the 1X view and the left view would 
be the 2X view; the slide plane would be the image plane of the objective.
Notice how the apparent width of the objects doesn't change, though they 
get closer and subtend a larger angle.  But the apparent depth _does_ change;
it decreases by a factor of two for 2X magnification.

John B

 


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