Re: [photo-3d] plain paper distance

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

----- Original Message -----
From: "ron labbe" <ron@xxxxxxxxxxxx>
To: "3D photo EGROUP 3D" <photo-3d@xxxxxxxxxxxxxxx>
Sent: Tuesday, February 27, 2001 6:23 PM
Subject: [photo-3d] plain paper distance


> Paul Talbot writes:
> >> the math will help figure out the farthest
> point at which he can place the piece of paper before troubles crop
>
> Actually, it DOESN'T MATTER how far away the piece of paper is (as long as
> no shadow falls on it), since there is no pattern to detect there is NO
> discernable parallax. If there must be shadow, just put the background
paper
> AS CLOSE as  you can get to the subject~

Exactly.   If shadows are a problem, use translucent paper (white, or any
color) and backlight it.  Alternatively, use black paper, preferably black
flocked.  Again there will be no shadows, and no viewable parallax since
there is nothing there that can be seen.

Another technique is to angle the camera up so that blue sky is in the
background, or down so that only the ground or other surface under the
subject shows.  If the subject is on the ground (like a bug or a flower),
there will be very little parallax on the background, because it is so
close.

 (math has it's place, but I can do
> without it in stereo photography for the most part)
>
> ron labbe
> studio 3D

Likewise.  It amazes me how many stereo photographers spend (waste?) so much
time calculating things, and then find out that it does not work anyway.
There are so many variables affecting our perception of depth that no one
rule could hope to apply to all situations.  Knowing what works under what
conditions is much more valuable.   I use math when designing equipment, but
not in photography.

Years ago, there was a trend to encourage math solutions in conventional
flat monoscopic photography.   Photographers were encouraged to carry
handbooks in the field.  Some of these, such as Photo Lab Index were over 3
inches (75mm) thick, and loaded with formulas.  These were sometimes useful
in the lab, rarely in the studio, and never in the field.   I don't ever
recall seeing a professional photographer carrying one.  The same thing
applies to stereoscopic photography.

JR




 

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