Re: [photo-3d] The Keystoning State

[Peter Davis <pd@xxxxxxxxxxxxx>]

At 09:02 PM 08/14/2000, you wrote:
> > > This seems like such a cool idea, but don't the mirrors introduce
> > > keystone distortion?
> > >
> >
> > So long as the vertical axis of the mirrors remains parallel with
> >the vertical axis of the camera backs I don't see how keystoning
> >would be introduced.
>
>If the mirrors themselves introduced keystoning, then wouldn't
>cameras such as the Loreo/Argus and many beam-splitter designs have
>the same problem? (Or worse since these systems bounce light off of
>two mirrors?)

They do.  Keystoning is one of the classic problems with beamsplitters.

I was thinking that if you take a picture of a brick wall, for example, the 
light path from one of the left/right edges is longer then the opposite 
edge.  That's what produces keystoning.  However, I think my analysis was 
faulty.  The light path to one edge will be a little longer before striking 
the mirror, and the opposite edge's light path will be a little longer 
after striking the mirror, so perhaps it all evens out.

-pd


--------
                                 Peter Davis
                  Funny stuff at http://www.pfdstudio.com
                  "The artwork formerly shown as prints."