Re: [photo-3d] Re: Camera separation in stereo photography

["don lopp" <dlopp@xxxxxxxxxxxxxxx>]

I think I know of one difference in measuring deviation >I cosider that when
one talks of  a deviation o2.5 this means a 2.5mm deviation osomething that
crosses infinity such as a tree , a building , a pole etc. because  if the
fore ground is water or grass, you can have much more deviation . That is
why I try not to have any vericles in the center of my pictures but I think
the allowable deviation should be based ona verticle in the center crossing
infinity which is often done by amature stereo photographers. Like I said
before,I don't  the maximum deviation should be used , instead I think
whatever wok should be used-up till a couple weeks ago I never measured the
deviation of my slides .I was under the impression that my stuff looked OK
,and that I was doing some thing right and I never liked exzagerated stereo
in any event. One of the best stereo shooters in our club,Warren Callahan
shot stereo with twin Konicas, 50mm lensesspacd 6 1/2 inches apart, usually,
allways having the nearest object at least 20 ft. away. He won many awards
and never had any hypers to worry about which is more than I can say about
most twin camera shooters. If my memory is correct, the couple that  present
the Anamorphic stereo slide show at the Conventions are conservative and
their shows are devoid of any hyper views which fits in with my view a poor
picture is not in any way improved by being presented in stereo. Don.
----- Original Message -----
From: "Greg Erker" <erker@xxxxxxxxxxxxxx>
To: <photo-3d@xxxxxxxxxxx>
Sent: Wednesday, July 05, 2000 12:33 PM
Subject: Re: [photo-3d] Re: Camera separation in stereo photography


> >All of my viewers have adjustable lens separation.You could be right
about
> >me being in th miniority as that is what appears to be bu still how does
one
> >explain the trriffic acceptance of your fie woks shot. I beleive that 35
mm
> >stereo requires more deviation thanMF because of the greater detail
> >available in the MF slides and the considerably less detail of 35mm. As
to
> >my tripod it is a standard hight eye level, no triks invlved but I do
like
> >to use filters. Don.
>
>   Okay, so it's not a lens separation problem.
>
>   Regarding my fireworks shot: maybe it's just
> a good/great photo, whether it has 1, 2 or 3mm
> of OFD.
>
>    You might want more _angular deviation_
> on a 35mm slide to compensate for less detail
> being recorded. But I doubt you want more
> _linear (mm) deviation_ since you view the
> 35mm slide with about twice the magnification
> of MF (thus giving you about twice the angular
> deviation for the same linear OFD).
>
> ---
>   Let's assume your camera lenses are 6 feet
> above the (level) ground and the camera is
> aimed horizontal (not tilted up nor down).
> For 6x6 format you have the following vertical
> angles of view:
>
> 75mm lens: 41 degrees
> 60mm lens: 50 degrees
> 50mm lens: 58 degrees
> 40mm lens: 70 degrees
>
>   With some trig we can figure out far away
> the ground comes into view for the various
> camera lenses. The horizontal (along the ground)
> and diagonal (from lens to visible point on ground)
> are:
>
> 75mm: 16', 17'
> 60mm: 13', 14'
> 50mm: 11', 12.4'
> 40mm: 8.6', 10.5'
>
>   If you are set up in a field of 3'
> high grass then divide all the numbers by 2
> since it's equivalent to having your tripod
> 3' above ground. 2' grass: multiply by 4/6.
> and so on.
>
>   So it seems to me that a person who could
> tolerate "normal" (2.7mm in medium format)
> amounts of OFD would have no problem viewing
> shots taken with any of these 4 lenses (assuming
> a normal 2.5" lens separation). Assuming no
> grass. 3' tall grass could cause problems
> I think.
>
>   But if you can only tolerate half as much
> then some of these may be hard to view. In
> which case you have to aim the camera upward
> a bit or stomp down the grass, or maybe find
> the top of a hill or mount to shoot from.
>
> Not mathophobic - Greg E.
>
>
>
>