[photo-3d] Re: Quiz #3 - stereo window

["Dr. George A. Themelis" <drt-3d@xxxxxxx>]

Now I am confused reading my very own postings! :)

Anyway, I wrote:

<< To place a better stereo window you must crop the left side
of the left picture and the right side of the right picture
(in equal amounts).    >>

And Mike Canter replied:

>Did I miss something, or isn't that backwards?
>Since we accept that the Left sees Less on the Left, don't you need 
>to trim the extra from the right side of the left image, and the left 
>side of the right?  What does it accomplish to take image away from 
>the left side of the left image, since there is already less there 
>to start with?

There isn't less there to start with... As you can see 
from my quiz picture no. 3, when I use a slide bar to
take a close up, there is more in the left side.  This
excess needs to be trimmed. Look at the bottom of:

http://home.att.net/~osps/quiz-answers.htm

>As I write this I hold in my hands an untrimmed set of prints fresh 
>from the lab and when I match up the nearest (foreground) set of 
>homologous points the right edge of the left print clearly hangs 
>out past the right edge of the right image.

It depends on the camera that you are using and the distances
of your nearest point.  If you use a camera without a stereo
window built-in (correctly: Stereo window at infinity) then
this should NOT be happening.  It is not happening in my
quiz picture no. 3 and I need to trim the outer edges of the
pictures.

But if you use a Realist-format camera with a stereo window
set at 7ft and your nearest object is at 15 feet, then this
will happen and if you want your nearest object at window
level then you have to do the opposite operation, i.e.
trim the inner edges of the prints.

You mentioned that you use a Burdlo and machine prints.
I do not know if there is a built-in window for this
camera and what kind of cropping is applied to the machine 
prints.

George Themelis