P3D Re: Realist system flawed?

[boris@xxxxxxxxxxxx (Boris Starosta)]

This responds to Dr. T's comment regarding magnification of Red-Button, and
Wageman's post in digest 2584:

>
>The Realist chip is the same height as a full-frame 35mm chip.  However,
>it is 5/8ths the width.  Or, put the other way, the full-frame chip is
>36mm/22.5mm=1.6 times wider than the Realist chip.

Okay, I agree.

>the focal length in mm.  The 50mm Pinsharp lenses give a magnification
>of 5x, whereas the slightly shorter Realist lenses give 5.682x.  (Think
[some arithmetic deleted here]

I think you are misunderstanding the comparison I tried to make.  I was
probably not explicit and clear enough.  I'll try again:

I was comparing inexpensive viewers available within the Realist _system_
with inexpensive viewers for 2x2 pairs.  Specifically, comparing the
apparent size of the _standard_ image frame in these viewers.  To my eyes,
using the cheapo Radix viewer (approx. 4x mag.), the apparent frame size of
the standard Realist image is indeed about one-half the size of the
apparent frame size of a full 35mm pair, _as viewed in the "Pinsharp."_

Thus, the one claim I made regarding _twice the image size_ applies to the
[Radix viewer/standard Realist frame] vs. the [Pinsharp viewer/standard 2x2
frame].  I also made another claim, that the Pinsharp gave a better view
than the Red Button, if you factor in image size, orthoscopy, and cost.
Perhaps you are confusing these two different claims.  (See my earlier text
below, for reference).

I do agree with you that the Red button viewer magnifies more than the
Pinsharp, all other things being equal.  But if we make all other things
equal, we are no longer comparing the Realist system with that for standard
2x2 mounts.

(Notice that, if only there was an inexpensive, widely available 35mm f.l.
viewer for the Realist format, literally all of my criticism of the system
would vanish!  Resultant orthoscopy would be complemented by an image size
even larger than the 50mm 2x2 standard.

I realize that the optics for such a viewer would likely not be
inexpensive.  So maybe the designers of the Realist system should have
settled on 50mm lenses and viewers, just to please me?  There are many
compromises that have to be made when designing for the popular market.
I'm just arguing they compromised in the wrong direction.)

>
>If you've never done so, Boris, I strongly recommend remounting a few of
>your images in full-frame RBT mounts, and view them in a Red Button
>which has been modified for 8-perf.  You might be in for a rather
>pleasant shock, if you have only the Pinsharp to compare against.
>
>     -Greg W. (gjw@xxxxxxxxxx)

I look forward to doing exactly that, with some of my computer pairs, which
I have mounted in both full frame RBTs and 2x2 pairs.

Thank you,


Boris Starosta




and, for reference, the earlier text, as posted:

>Excuse me?!  You mean the single-element plastic pin sharp viewer that you
>are using is of higher quality than the Realist red button or Kodaslide II
>viewers????   (- Dr.T.)

Yes, precisely.  The Realist red button or Kodaslide may have better
optics.  But my entire argument rests upon the relative importance to
stereo slide viewing of these additional qualities: apparent field of view,
orthoscopism, cost.  Adding up all of these advantages of viewing 2x2
stereo pairs in a "Pinsharp," the Realist format viewers don't even come
close.  I invite a newcomer (Xochi?) to take in some stereo views using
both types of formats, and give us their impressions.

Remember, the full 35mm frames produced by my twin rig are some 50% larger
than those coming out of a "standard" (5p? ANSI?) Realist.  Add the
relative "enlarging" effect of the proper focal length in the inexpensive
"Pinsharp", and with 2x2 slide pairs you have a stereo view that is
practically double the size of a Realist slide viewed through the
inexpensive Radix viewer.

(-Boris)












Boris Starosta

usa 804 979 3930

boris@xxxxxxxxxxxx
http://www.starosta.com
http://www.starosta.com/3dshowcase

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