Re: [photo-3d] Re: Alternative Quiz (#3)

["John A. Rupkalvis" <stereoscope@xxxxxxxxxxxxx>]

----- Original Message -----
From: "Bruce Springsteen" <bsspringsteen@xxxxxxxxx>
To: "Photo-3D" <photo-3d@xxxxxxxxxxxxxxx>
Sent: Sunday, March 04, 2001 7:49 PM
Subject: [photo-3d] Re: Alternative Quiz (#3)


> Can the camera be moved
> in such a way that the two images are already framed for a "proper"
> foreground window, without further trimming?
>
> George got the idea and said:
>
> > You have to shift the camera (I think there is a proper
> > term in cinematography for this kind of camera movement,
> > but I do not know it) and at the same time converge the
> > camera to where you want your stereo window to be, i.e.
> > at your nearest object (or a little bit closer).
>
> This would be a dolly shot *combined* with a pan, where the camera is
> rotated about a vertical axis, keeping the line of sight "toed-in" on a
> point nearer than the nearest object.  Would this successfully put the 3-D
> scene behind the screen?  How exactly?

Yes, this works real well.  Actually, this is not too uncommon in
cinematography, although with a slightly different purpose.  During a dolly
shot, it is usually desired to keep the main subject, such as an actor who
may be speaking a line of dialog, in one position on the screen.  The camera
operator pans the camera in the reverse direction of the dolly move, so as
to keep the actor in the same position in the frame.

For time parallax stereoscopic images, you can actually choose where you
want convergence (the stereo window), by simply reverse panning so as to
keep an object at that chosen distance "standing still" in the frame while
the dolly moves the camera laterally.  This will automatically give you the
amount of toe-in that will correspond to the stereo window.  Anything that
does not move in the image during a dolly move will always be at the plane
of convergence, or the stereo window.

I used this technique when I videotaped the rock bands in the Pulfrich 3-D
video "30th Anniversary of Rock'n'Roll" (It was low budget, so I was D.P.,
camera operator, and stereoscopic consultant; all for the price of one).

JR


 

Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/