P3D Re: Instant Anaglyphs

[Peter Homer <P.J.Homer@xxxxxxxxxxxxx>]

Tom wrote:
> Brian Reynolds asked:
>
> >Assume I built a box camera (to take a Polaroid 4x5 film
> >holder/processor) with two pinholes (or lenses) at the proper
> >distance (lets say 60mm).  If I then covered the left pinhole with
> >a red filter and the right with a blue filter and shoot with color
> >film, will I get a proper anaglyph (i.e., not pseudo)?
>
> It sounds like a fine idea, except that it won't work.  Ain't it
> always like that?  You wouldn't get a good anaglyph, stereo or
> pseudo.  Using this scheme you would obtain color separations, not
> anaglyphs.
>

Actually I planned on using color separation filters.

> In other words, imagine what happens if you shoot a photo of a red
> and white striped ball.  To the green lens, it looks BLACK and
> green!  To the red lens, it's solid red.
>

>Well perhaps I was unclear about one of the camera details.  I
>intended to have both the left and the right pinhole expose the same
>piece of film with no septum or other separating device.  The image
>formed by the red and green pinholes should merge to form a single
>image.

Yes but with a 60mm seperation the rays would have to travel a lot further
than with a normal stereo camera in order for them to ovelap and by then
they may not be in focus even with pinholes. I have experimented with a
camera obscura  with 50mm seperation pinholes and even at about 295 mm from
holes to screen the images do not fully overlap yet at that distance they
are  already badly out of focus. Leonardo-Da-Vinci drew a double pinhole
camera obscura with the pinholes offset from the centre for some reason and
with no septum .The rays were drawn with one set falling partly on the side
rather than back wall which would be correct because of the offset, and as
seperate bundles which did not ovelap which  is also probably correct . He
seems to have drawn the device from life complete with the fault of the
offset pinholes so the drawing is probably accurate.
 You might do better to make it a reduced seperation macro device which a
pinhole camera should be good for.

> And it doesn't matter because, the images would not be oriented
> correctly, as you guessed. (Realist format users are frustrated by
> their inability to freeview a film strip for the same reason.)  Then
> there is another problem.  This arrangement would yield two images
> spread far apart, instead of one on top of another like an anaglyph.
>

What if I put the red filter on the right pinhole and viewed with the
red filter over my left eye?

That is my thinking to and I dont se why it should not work.
 The pinhole group you mention sounds interesting especialy there use of
multiple pinholes is the intention here to produce stereo pairs. P.J.Homer



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