Re: Hyperstereo threshold

[bercov@xxxxxxxxxxx (John Bercovitz)]

> Where:
>
>     B  = Base separation
>     D  = Deviation on film
>     F  = focal length of lens
>     S1 = distance to near object in picture
>
>          B * F
>   S1 = ---------
>            D

And of course D should be ~1/30th of F so the equation reduces to 

S1 = 30 * B

But I caution, this is a very conservative formula.  I've done 15 * B
numerous times and it works fine in a hand viewer.  There are of course
some problems when you have non-standard parameters and you project.

> Thanks for the replies. I guess what I really want to know is what 
> kind of aesthetic impact the 90mm separation will have.

I think there are a lot of twinned P&Ses out there which are right
around 90 mm separation.  When I see their slides projected at the
club meetings, I can tell pretty easily that the people in the scenes
are perfectly-formed midgets.  Actually, it's nto that bad but people 
do look small.  There was a slide of people in a grocery store taken
with, now what is it Elliott likes to twin?  Anyhow, the people looked
small and so do the height of the shelves and the aisles looked narrow
and so on.  When I asked, I found only about 1/3 of the audience noticed.

John B