"Tek" <tek### [at] evilsuperbraincom> wrote:

>
> The only squashing effect I'm aware of is when viewing through a telescope,
> which is the same flattening effect you get with a zoom lens, this image has
> a non-zoomed field of view so you wouldn't see squashing.
>
> The squashing is because the more you zoom in, the narrower your field of
> view, the closer to parallel the edges of your view become, so the less
> perspective you have in the image. With a wide field of view objects further
> away get a lot more perspective, so get smaller quicker, a zoomed lens keeps
> things much more similar sizes.

Hmm, that *would* seem to be the case, even in the situation I'm thinking of.
Maybe I'm wrong about the whole idea. But I'm imagining, say, the planet Mars:
If it were perhaps far larger in actual size (to take up an area in the sky two
or three times the visible diameter of the Moon, for example) while still being
so far away, it seems to me that the 'perspective' of the 'closer' and 'farther'
parts of the disc would be foreshortened. Based on the idea that, relative to me
as the observer at such a distance, the 'distance difference' between the closer
and farther parts would be quite small, relatively speaking.  I guess I just
need to do an experiment, to prove or disprove it to myself. (I have an image in
my mind of what I think it should look like--but maybe that's a false image!)

There's actually a 'down-to-earth' example that I've looked at, which *seems* to
show this effect:  It's a giant crane hoist (a *really* big one) at a Navy yard
near me. It has an elevated 'track' (that the crane runs on) which is probably a
good 300-feet long. When that track is rotated to be 'in line' with my line of
sight, it's near and far ends appear to be just about the same size
visually--almost no perspective distortion, in other words. (And I can only view
it from far away--not close enough to show the normal perspective distortion--so
an unfortunate side effect is that it 'looks' quite small.)

Time to experiment! :-)

Ken

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