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[P3D Gabriel Jacob <jacob@xxxxxxxxxxxxxx>]

>Neil Harrington writes
>It's probably possible to get into yet another word-hassle over "beam," but
>I'm reluctant to do so.  I'll settle for pointing out that "beam," the verb,
>does not really carry the same meaning or implications as "beam," the noun.
>It is correct to speak of sunbeams, for example, but the sun does not _beam_
>light in any one direction as a headlight does; it radiates pretty equally
>in all directions.  A beam of light, whatever the source, is a directional
>thing practically by definition, but that doesn't mean or imply that the
>source was directional.

Well guess what I have beammed the Sun! Very easy to do also.
Just take a mirror and you can beam the Sun in any other direction.
Thus you achieve two objectives. First you redirect the Sun light 
and you create a Sun beam.

Now getting back to 3d thing a ma jig we are trying to define, it is
called a beamsplitter. Technically might not be correct but it describes
what in effect it SEEMS to do. Since most of us know what we are talking 
about when we call it that in a 3d context, I think it is therefore correct.
A 3d beamsplitter describes what it achieves and not what it does.
As others have said and I will add to it, it does not split any beams but
in effect it takes different beams and redirects it to one lens. A 3d camera
has two lenses, so it just intercepts those two beams but a beamsplitter 
converts a single lens to intercept two beams. It seems that the 
beamsplitter took a single beam that the one lense camera would see and
introduced to it two beams. Its true they are not identical beams and
therefore never split, but I repeat its not what it does but what it
does but what it seems to do to a single lens.

Now would a Loreo camera be considered a beamsplitter. Oh no we
are digging a big hole here now. No it would not be considered a
beamsplitter camera because it uses two lenses. It does use
the beamsplitter arrangement that is used to convert single lense
cameras but as I said it uses two lenses therefore it uses the
beamsplitter arrangement for a different purpose. In the Loreo it 
uses it, to change the Stereo base while it maintains side by side 
pictures in the film. This would not be possible with a regular
3d camera. 

Now finally I would like to know who introduced this term beamsplitter.
Its funny because someone posted a question to that effect a few digests
before. They asked whoever came out with the beamsplitter, what did
they call it. Coincindentally I had the evening before thought about
this also. I have always known it as a beamsplitter. But who introduced 
this terminalogy to me? The reason I ask this is because I am relatively
new to this group, so I did not have much contact with other 3d people.
But I have always known it as beamsplitter. So I said to myself as
someone else asked lets go to the source. I happen to have a Pentax 
beamsplitter so I went and dug it out of the attic. I checked the box,
the booklet, everything. Guess what folks? There is not one single mention
of the word beamsplitter! They call it stereo adapter! Simple as that.
I guess people from optical background are more careful with their terms.
Still I see no problem with calling it a beamsplitter in a 3d context or
calling it a 3d beamsplitter when we are not sure in what context we 
should be in. By the way, in the Fuji single use beamsplitter I could not
find beamsplitter on it also. But then it was all in Japanese and I could 
not read it. Maybe the Japanese fellow that has posted about the Fuji 
Beamsplitter can tell us.
   
Incidentally I have used the Pentax beamsplitter with a video camera and
it works pretty well. I had a problem to view it with my 27 inch set so
I took my stereoscopic viewer and looked at it with my 4 inch black and
white set and lo and behold I had 3d video!

Anyways thats my 2 cents (CDN) worth or 200 cents worth.
Bye for now.

Gabriel Jacob
jacob@xxxxxxxxxxxxxx


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