Re: [photo-3d] 1/30 rule for video!?

["sergio baldissara" <winter@xxxxxxxxxx>]

yes, some assumptions come from physiological observation... of 
course there are physiological differences between individuals... 
even in attitude to binocular fusion!
of course I can dare, but I've better to be conservative if I want to 
be sure I'll capture stereopsis of all my audience. Of course the 
reverse is also true: the more my shiftings on film (and on screen, 
if they are express it by a figures or fractions) will approach the 
limits, the more my effect will be spectacular...
Ferwerda recommends 1.2mm on 135 film and <3mm on 120, others about
2°
in projection... (2*tang[2°/2]=0.035, say about 1/30)... I indeed 
know little about motion pics or videos, but I don't believe they 
differ from stills.
Sergio

--- In photo-3d@xxxxxxxxxxx, Owen Pearn <owenp@xxxx>  wrote:
>  as far as i've been able to determine from the human factors 
literature
> and my own experiments, the maximum deviation is related to angular
> disparity created at the eye.
> 
> by trignometry, this means that viewing distance is the driving
> parameter.
> 
> lenny lipton recommends a maximum of 1.5 degrees of uncrossed 
parallax
> (behind the presentation plane). note that it seems as though 
humans in
> general can tolerate a little more than that of crossed parallax (in
> front of the presentation plane) but i use 1.5 degrees for both.
> 
> if my math hasn't failed me, the relation is: 
> 
>   maximum deviation at the presentation plane allowed at a given 
viewing
> distance = the viewing distance * 0.02618
> 
> and conversely:
> 
>   minimum viewing distance for a given deviation at the presentation
> plane = the deviation * 38.2
> 
> i usually round up to 40 when i'm doing these calculations in my 
head:
> 
>   deviation = distance / 40
>   distance = deviation * 40
> 
> as a starting point for more info, i recommend:
> 
>   http://www.stereographics.com/html/chapter_2.html
> 
> -o-
> 
> boris@xxxxxxxxxxxx wrote:
> > 
> > Sergio Baldissara wrote to the glamourphoto group:
> > 
> > >Sorry for my (perhaps non pertinent) intrusion... can I know 
what videos
> > >you're talking about and what stereo method was employed?
> > ...
> > >THE MAXIMAL DEVIATION BETWEEN 2 MATCHING POINTS SHOULD NOT BE 
GREATER THAN
> > >1/30 OF BASE (HORIZONTAL SIDE) OF THE FRAME (or screen.. say
2° 
parallax)
> > >anyway if you want formulas...  
http://home.mira.net/~kiewavly/bases.html ;
> > >is it possible the movie-makers ignored such simple rules?
> > 
> > Harold Baize was talking about videos using frame alternate 
format.  But I
> > believe the discussion related to anaglyph as well.
> > 
> > Sergio, not another rule flattening out what might have been good 
depth
> > pictures?  1/30 sound too small!  On my monitor, which is 30cm 
wide, you
> > are recommending a deviation of no more than one centimeter.
> > 
> > Is the recommendation for this maximum deviation based on any 
physiological
> > principles?  Does the fact that motion will be shown recommend 
the use of
> > smaller deviations in a picture?
> > 
> > I would think that for video, because of its lower resolution, 
more
> > deviation would be necessary for a reasonable range of depth to be
> > apparent.
> > 
> > Boris
> > 
> > - Science is the part of culture that rubs against the world.
> > -
> > -                                     Stanislaw Lem, _His 
Master's Voice_
> > 
> > Boris Starosta                        boris@xxxxxxxxxxxx
> > Stereoscopic Art & 3-D Photography    http://www.starosta.com
> > usa - 804 979 3930                    
http://www.starosta.com/3dshowcase


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