SL3D some more

[P3D <PK6811S@xxxxxxxxxxxxxx>]

Allan Woods:

>It becomes separated pairs when you make gross changes in the design
>of the system - (something which, so far, Paul Kline has not been
>able to succeed in doing!)

One of the common mistakes using mail-list communication is believing that
all parties are as familiar with your previous posts as you are yourself :-)

At least a year ago I described my first SL3D lens, inspired
by discussion between William Carter and John B, covering theory
but way short on implementation detail.  Fortune presented me with
a disassembled 135mm 2.8 lens which was missing a diaphragm.  So I
punched two holes in a piece of construction paper, applied the
red and blue filters, put that in place of the diaphragm, reassembled the
lens and started shooting.  Just looking through the viewfinder and 
focusing on items such as see-through window decorations I could see
the red and blue images sliding over each other and knew it would work.
The 'how' understanding came later - and is still growing.

It works.  I have pictures!  Several 8x10's are hanging on the wall 
confronting me across the desk every day.  Perhaps, Allan, you would
like one too?  :-)

It does have limitations, some of which may not be overcome.  The system
does not create a holographic 'in-the-round' image, just a stereo pair.
The overall colors are off, though some images are much better than others.
The stereo base is limited to the lens pupil diameter, metering and
colored-vignetting are problems.

I think I understand that last now, after staring through a pair of
50mm 1.4 lenses last night, one modified with red/blue filters.
Look through the front of the lens at a broad light source (sky).
Slowly pivot it at the middle, left to right, watching as the front
and back housing cross the pupil.  They should meet in the middle if
the lens has no vignetting problem.  In other words, what is
obscured by the rear casing is always balanced as the front casing
obscures the opposite side.  Of course this is going
to be a problem if the aperture is off-axis, as they are in SL3D.
It is much worse with the 50mm lens than with the 135mm, but
I have another mask idea to try which may help.

Paul Kline
pk6811s@xxxxxxxxxxxxxx


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