Re :Bi-Ocular dveices

[P3D Peter Homer <P.J.Homer@xxxxxxxxxxxxxxxxx>]

Alan woods writes "Just to clarify things a bit ,the  3-d info IS the depth
of field you want to disard as "poor". William Carter refers to that as
"Z-axis resolution."

Actualy I dont want to discard it at all I want to make it sharper . Which
is not easy with a microscope as the only irises normaly fitted are in the
condenser below the specimen and in the light source .Neither has any
noticeable effect on the depth of field if stopped down and that is not
their function anyway. The only other iris available for microscopes that I
know of is one that is fitted to a X100 oil immmersion objective to enable
its numerical aperture to be reduced to unity from something like 1.25 or
more.
This might do the trick as it in aproximately the same position as in a
camera lens but I dont have one to try. There will however be a loss of
resolution as the numerical aperture is reduced this is likely to happen
with any stop down iris applied to a microscope. The real use of this iris
is high power dark ground with a dark ground condenser which canot provide
a wide enough cone of light for a N.A. of more than unity.
 The type of microscope I had in mind was not the anaglyph version with
red/green filters in the condenser  and eyepieces  which does seem to
depend in part on out of focus effects like the Q-Dos lens which was not
the theory behind it in the book where I read of this method. Without the
eyepiece filters in you do see double images which seperate further the
more out of focus they are. What I was refering to was the polaroid method
and the inherent stereo which I find is present before the addition of any
filters.
  Resolution in a microscope is defined as the minimum distance between to
objects which can be seperated I.E. for light microscopes a maximum of
about 1/4 of a micron or 250 mu. I dont think Z axis resolution is a good
term for what we are talking about here which is DOF.

"When I look with my own eyes ,the world looks NOTHING like a realist
slide. I dont see everything in focus regardles of distance, nor is
everything perfectly lined up parallax-wise between my eyes."

The world often looks nothing like a realist slide to me as well but
because a slide may show some lack of DOF whereas reality almost never does
unless it includes very close up aproaching minimimum distance of distinct
vision which is around 25 cm and infinity. Even then the problem is more of
fusion than focuss so if I sacrifice stereo and shut one eye I can do a
little better.
 Probably this not just due to DOF although I think this is high and the
pupil at its widest seems to be quite a small aperture But to the "
autofocuss" of the brain and eye rapidly adjusting to compensate so that
reality never appears to lack DOF the way a slide can.
                                      P.J.Homer



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