Mailinglist Archives:
Infrared
Panorama
Photo-3D
Tech-3D
Sell-3D
MF3D
|
|
Notice |
This mailinglist archive is frozen since May 2001, i.e. it will stay online but will not be updated.
|
|
P3D Re: Projection problem
- From: Gabriel Jacob <jacob@xxxxxxxxxxxxxx>
- Subject: P3D Re: Projection problem
- Date: Wed, 1 Sep 1999 20:08:37 -0600
Tom Hubin writes,
>So, now I am puzzled. I would expect the stereo slides to be mounted for
>a handheld viewer. Not inverted, emulsion surface toward the viewer's
>eye, right slide directly in front of the right eye. Eyepiece lens
>allows viewer to focus on slide only a couple of inches away. No image
>inversion. Light source behind the slide.
The emulsion faces away. As was mentioned, this is determined by the
emulsion orientation in the camera and is the best solution optically
because the light doesn't have to go through the film base in the camera.
It's better to get it right when recording. After that (recording),
there is no choice in the emulsion orientation if you want to view the
image in the proper orientation (non mirror image) be it 2-D or 3-D.
Therefore, it faces away, in the camera, in the viewer, and in
projection (as we shall see).
>Then the slide should be inverted for projection but not right/left
>swapped if you still want the emulsion surface on the image (screen)
>side.
As I mentioned above, the emulsion has to face away from you in a
viewer for proper viewing. In the projector, the emulsion still has
to face away from you (toward the screen), otherwise you'll get
a mirror image. Of course the image also has to be inverted, to
project right side UP. Since a stereo pair is on single mount,
inverting the images and keeping the emulsion towards the screen,
results in the left image now being on the right side (of the
projector) and the right image on the left side.
Now since the right lens is projecting the left image, the 3-D
glasses has to block the left image from being viewed by the right
eye. Therefore putting 3-D glasses in front of the projector (with
the temple frames facing backwards, away from the screen) so that
the right side of the glasses is on the right projector lens will
result in the light being blocked (and correspondingly on the left
projector) from that side. End result is the left eye sees the left
image (projected from the right projector lens). Confusing enough!?!
;-).
>So what part do I have wrong? Do you mount in a handheld viewer with
>emulsion side toward the light source?
The emulsion orientation was the root of the problem.
P.S. Since we're on this subject, it's common knowledge that
reversing anaglyph glasses, so that the left (normally) red filter is
on the right eye, will result in pseudo 3-D. What is not commonly
known, is that reversing polaroid glasses the same way will result
in nothing! ;-) What I mean is that regardless of how the glasses
are oriented, the viewer will see the 3-D image correctly. The only
way of viewing pseudo is by turning the glasses 180 degrees away
from you. This was designed by the clever 3-D projector designers
so that regardless of which way you put on the glasses, you won't
get pseudo!
P.P.S. Sometimes 3-D reminds me of a Rubik's Cube!
_G ab ri e_l _G a br ie _l jacob@xxxxxxxxxxxxxx
| \ you |\ / \ you / \
| seeing | / seeing /
.----._.----. .----._.----.
| 3D / \ 3D | |3D / \3D |
'---' '---' '---' '---'
|