[MF3D.FORUM:547] Re: Exact fl match for paired lenses.

["Bill Glickman" <bglick@xxxxxxxx>]

Some of the responses leads me to a question, I am confused what the proper
answer is.  If one shoots with subjects from 8 ft to 20 ft, and instead of a
stereo base of 65mm, I use my min. base of say 125mm, 2x larger than John
B's formula suggest.  IF the shot was taken proper, no toe in, cameras
parallel, no camera tilt, etc..... Is the consensus that these shots, if
mounted properly will view  perfectly fine  - as if the base was 65mm, the
only difference being a bit more feeling of depth?  IF so, I mis-interpreted
my poor results, and am motivated to find what else could have went wrong.

      The reason I felt the problem is the excessive stereo base was process
of elimination ...... I used one camera on the slide bar and took the left
shot, then moved the camera to the right 65mm and mounted the second 80mm
lens on for the right shot..... when I did this, the images viewed in
perfect 3d with no edge problems.  In my mind, this eliminated the separate
lenses as being the source of the problem.  The only thing that differed in
all my double edge shots was the excessive stereo base.

    Tom, the best way to describe the edge is this..... when the center of
the image fuses, then the edges don't.  The lack of fusing on the edges
causes me to see two edges on the left and two on the right.  I also see
double imaging towards the edges in a gradual way.

       The cameras were on a solid stereo bar and appeared to be perfectly
parallel, no toe in,  have identical tilt and were very level.  They were
shot at the same focus distance and same f stop / ss.

Regards
Bill G


> > The left edge and the right edge have tremendous double
> > vision,
>
> No one has suggested the possibility that the cameras are toed-
> out.
>
> Bill are you sure that both cameras are aligned perfectly
> parallel? A very slight degree shift can translate to quite a
> difference in the image framing which can lead to the extra
> material you are seeing (or not seeing as the case may be).
> This sort of misalignment will also produce a keystone effect
> which may or may not be noticable depending on how great it is.
>
> Just a thought.
>
> That's all for now,
>
> David W. Kesner
> Boise, Idaho, USA
> drdave@xxxxxxxxxx
>