Re: [photo-3d] Beam splitters vs. Image splitters

[Brian Reynolds <reynolds@xxxxxxxxx>]

Bryan Mumford wrote:
> If you are willing to educate me further, I'm curious why beam 
> splitters are used in photography. Why do you wish to capture the 
> same scene on two cameras?
> 

By using a beamsplitter you can get the optical axis of the two
cameras arbitrarily close.  This means that you can use a very small
inter-axial distance to take macro stereo photos.

For non-stereo uses a beamsplitter allows the camera and another
instrument to see the same scene.  Some Canon cameras use a
beamsplitter (or the moral equivalent) instead of a reflex mirror.
One beam of light goes stright through the camera to the film and the
other goes up to the light meter and viewing prism.  This scheme means
that they don't have to worry about camera shake due to a moving
mirror, or the delay in firing the shutter after the mirror moves out
of the way.

-- 
Brian Reynolds                  | "Dee Dee!  Don't touch that button!"
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