[MF3D.FORUM:1019] Re: Deviation, the stereo window, definitions

["David W. Kesner" <drdave@xxxxxxxxxx>]

Abram Klooswyk writes:

> David Kesner:
> >If I had two film chips where the deviation between the near 
> >points is 2.0mm when the far points are homologous and I then 
> >mount (place the window way forward) so that the far points 
> >are 2.0mm apart it would spread the near points to 4.0mm. 
> >There is still only 2.0mm between the near and far points, 
> >but there is 4.0mm total deviation between homologous points.
> 
> Sorry, David, I cannot make sense of this in my usage of
> the definitions of homologues, separation, deviation.

Using your definitions this would read:

If I had two film chips where the separation between the near 
points is 2.0mm when infinity is zero deviation and I then 
mount so that infinity points are now separarted by 2.0mm in 
relation to the mount aperture spacing then the same near 
points would be separated by 4.0mm.

The point I am trying to make (and not doing so very well) is 
that there is a point at which you can no longer comfortably 
view an image because the "separation" between homologous 
points is too great. This "separation" can be made too great 
by improper mounting even though the actual "deviation" is 
within tolerable limits. By the same logic an image that is 
outside the tolerable limits of deviation can in some cases be 
made more viewable by mounting that decreases the separation 
of the homologous points.

Did I do any better at trying to explain myself?

That's all for now,

David W. Kesner
Boise, Idaho, USA
drdave@xxxxxxxxxx