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Re: [photo-3d] focus and convergence again


  • From: "John A. Rupkalvis" <stereoscope@xxxxxxxxxxxxx>
  • Subject: Re: [photo-3d] focus and convergence again
  • Date: Sat, 14 Oct 2000 11:09:15 -0700

I don't know how to make this more clear than what I have already said, but
I will try.

If someone is myopic (nearsighted), their eyes will deconverge (sightlines
approach parallel) the further away the object that they are looking at is.
But the eyes will not focus on that object.

Likewise, if someone is presbyopic (farsighted) their eyes will converge on
objects that are close to them, but again the eyes will not follow focus.

Whether you can or cannot focus on something is a different function than
that of convergence.  I have already pointed out several instances where one
function is performed independent of the other.

Stereoscopic viewing (viewer, projected, holographic, lenticular, free-view,
whatever) is dependent on this ability to focus and converge at different
distances, and millions of people do it all the time.

JR

----- Original Message -----
From: "ron labbe" <ron@xxxxxxxxxxxx>
To: "3D photo EGROUP 3D" <photo-3d@xxxxxxxxxxx>
Sent: Saturday, October 14, 2000 6:52 AM
Subject: [photo-3d] focus and convergence again


> JR writes:
> >>I would agree that focus and convergence are usually coordinated
functions
> in that they usually occur simultaneously and by similar amounts, but they
> certainly aren't "linked".
>
> To make this more obvious, consider the situation of "synchronized
> swimmers".  Their actions may appear to be identical, and they are
> performing in the same medium (water), but it would be incorrect to state
> that they were "linked".<<
>
> I can't agree with this (OBVIOUS?) comparison at all! The two swimmers are
> consciously making an effort to coordinate their efforts, but one does not
> have to consciously focus their eyes at the same time they are converging.
> One goes through the three dimensional world with those two eye functions
> NORMALLY LINKED: when you look at something far away, your are focussed
AND
> converged far away. When you look at something close, you FOCUS and
CONVERGE
> on something close. This is normal and as unconscious as breathing. Of
> course, they CAN be unlinked! But the only time I can think of when they
> ARE, is for the stereoscopic illusion of three dimensions, when you are
> focused at one place, but converged at any distance... when else?
>
>
> ron
>
> ron labbe
> studio 3D
>
> mailto:ron@xxxxxxxxxxxx
> http://www.studio3d.com
>
>
>
>
>
>