Re: [photo-3d] Are beamsplitters crappy?

[pd@xxxxxxxxxxxxx]

John A. Rupkalvis writes:
> 
> ----- Original Message -----
> From: <pd@xxxxxxxxxxxxx>
> To: <photo-3d@xxxxxxxxxxx>
> Sent: Tuesday, January 09, 2001 8:35 AM
> Subject: Re: [photo-3d] Are beamsplitters crappy?
> 
> 
> >
> > Bryan Mumford writes:
> > > sstiles pointed us to the web site http://www.3dquarium.com
> > >
> > > I looked at this web site and the sample images. I was struck by my
> > > dissatisfaction with the images taken with their beamsplitter. It
> > > leaves a very narrow image space for the stereo pair. I suppose this
> > > is unavoidable, but I had not seen it demonstrated before. Would
> > > others agree that beam-split pairs are unsatisfactory? I didn't think
> > > about it this way before, but I'm getting four times as much picture
> > > data in two full frame cha-chas than I would get in a single frame
> > > split image. Maybe a beamsplitter is not a worthwhile project after
> > > all.
> >
> > This has been discussed before.  A splitter does, of course, split the
> > frame, so you only get half the area for each half of the pair.  On
> > the other hand, you can get moving subjects, sports, etc. in a way you
> > can't with the cha-cha method.  Those are only two options:  there are
> > also full-fledged stereo cameras available for anywhere from about
> > $100 up to $4000 and more.
> >
> > You could try to build a splitter in the style of the Tri-Delta
> > Prism.  This places two images, rotated 90 degrees, on one frame of
> > film.  The result is that each image is about 18mm tall and 24mm wide
> > on 35mm film.
> >
> > -pd
> >
> An image splitter does split the frame.   A beamsplitter does not.   Using
> ordinary 35mm still cameras, the frame is about 24mm tall and 36mm wide.
> The full frame area is utilized, with no loss (see my other postings).

Thanks for clearing this up, John.  I think your point is taken that
"beamsplitter" properly refers to a half-silvered mirror.  However,
the term is also commonly (mis)used to refer to stereo adapters, and
that is the subject of this conversation.  (Note that I simply used
"splitter" with no qualifiers.)

-pd



-- 
--------
                             Peter Davis
               Funny stuff at http://www.pfdstudio.com
                 The artwork formerly shown as prints
    List of resources for children's writers and illustrators at:
                  http://www.pfdstudio.com/cwrl.html