Re: John!!!

[P3D John Bercovitz <bercov@xxxxxxxxxxx>]

> And, we (i.e. people) do not rely solely on the two eyes to perceive,
> or think we perceive depth. 

Agreed.  There is a very long list of depth clues.  It is highly 
controversial as to whether focus is one of them or not.  Some
researchers believe they have detected an extremely weak ability
to sense depth by focus and others say it ain't so.  By weak, I 
mean that some have shown that a person can tell the difference 
between a point one foot away and a point 20 feet away by focus.
This is not even within an order of magnitude of the sensitivity
of the parallax system.

>> Maybe Bill's system uses "circle of confusion" as the encoding path 
>> but people don't.

> Ah, this is fodder for another one of those never-ending opinion-fests...
> but, I believe they DO! (use "circle of confusion").

Allan, it has to be more than belief.  That's not the foundation 
for the scientific method.  In the little old lady's immortal words,
"Wo ist das Rindfleisch?"  Belief is a great place to start.  Then
the work begins.  

As a conjecture, it certainly seems reasonable that the brain will
consider an out-of-focus spot lying near (in the field of view) to 
an in-focus spot to be at a different distance than that in-focus spot.  
It's not one I've personally read about but it seems reasonable.

However!  Bill's system does _not_ use the "out of focusness" to provide 
the depth cues.  In Bill's system, the depth cues are presented to the
eyes as parallax.  His lens uses the separation of the pupils to create 
the parallax, not the "out of focusness".  "Out of focusness" is an 
unfortunate byproduct of not having stopped-down apertures, not using the 
smaller pair of apertures which David Burder, for instance, uses.

> Come to think of it, I've noticed that more and more things have
> gotten out of focus.  Do you suppose that is yet another effect
> of nuclear testing or over-population or ozone depletion or chemicals
> in the water supply?  I've never seen so many out of focus things as 
> there seem to be around these days...

I've noticed that too.  I think that part of the problem may be that time 
doesn't seem to be frozen anymore - someone turned on the aging machine.  
Optometrists have a palliative, though.  I wear 'em.  888-)

John B


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