skip this for beamsplitter.

[P3D Gabriel Jacob <jacob@xxxxxxxxxxxxxx>]

Paul S. Boyer, thanks for your informative and interesting comments on
dictionaries and terminalogy. Believe it or not I agree with almost 
everything you said. 

Neil Harrington thanks for clarifing what you meant by sunbeam. Again
I agree with most of what you said about the Sun beam origions.
On the other points let me clarify what I meant.

>>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, 
>
>I agree with most of what you're saying up to this point.  On just one point
>I would make a correction:  The mirror attachment doesn't "[take] a single
>beam that the one [lens] camera would see" and do anything with it, because
>any single beam that the one-lens camera _would_ have seen never becomes
>part of the process at all--it falls between the two outer mirrors and
>therefore doesn't contribute anything to the image on film.  What the mirror
>device does is intercept the separate and different beams that _would_ have
>gone to two separate lenses in a conventional stereo camera, and redirect
>them so that they pass through the existing single lens.
 
Again I agree with the above but thats what I am saying also. If you notice in
my original post I mention it "SEEMS that that the beamsplitter took a single
beam". I go on and state that "they are not identical beams and therefore 
never split", just like you state in "What the mirror device does is intercept
the separate and different...."  i.e. I say not identical, you say different.;-)



>Thus, if anything, the device would be better called a beam-joiner than a
>beamsplitter.

Yes I agree.

>>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. 
>
>You see, this is exactly the problem with accepting incorrect terminology:
>it leads to and encourages further incorrect terminology.  _Why on earth_
>would anyone call the mirror arrangement in a Loreo camera a "beamsplitter"?
>All the mirrors do in a Loreo is extend the stereo base.  The optical paths
>are entirely separate from each other until they reach the film plane.

Yes in agreement again. That is a problem with incorrect terminolgy.
All I was trying to convey is that the same arrangement that Pentax uses
is used in the Loreo in front of their two lenses. You say "All the mirrors
do in a Loreo is extend the stereo base." I said "In the Loreo it uses it,
to change the Stereo base". Again we are in agreement. One small point thou.
The mirrors do actually extend the stereo base but the design consideration  
here was to combine the picture side by side for normal processing. If they
wanted simply to extend the stereo base they could have dispensed with
the mirrors and just rearrange the two lenses, and copy a realist or
other regular 3d camera. Beam-joiner anyone?


>>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.
>Do me a favor and take out the manual that came with your Pentax STEREO
>ADAPTOR. Now look through it carefully, page by page, and see how many
>occurrences of the word "beamsplitter" you can find.  I can give you the
>number right now: zero.  The manual repeatedly refers to the device as a
>Pentax Stereo Adaptor, and nothing else.
 
Again we are in complete agreement! If you check my original post thats exactly
what I said. See above. I am not sure where I went wrong. I don't think I
could state it clearer. You say, check my manual for the word beamsplitter,
and go on to say it refers to it as Stereo Adaptor, hey thats what I said,
"not one single mention...! They call it stereo adapter!".

Thats all folks!
Bye for now.

Gabriel Jacob
jacob@xxxxxxxxxxxxxx



------------------------------