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

[Greg Erker <erker@xxxxxxxxxxxxxx>]

>I think  the diviation numbers given are eronious or being measured in a
>strange way  ? I shot some today [ MF] at 1,2 and3 mm icouldnt use the 3mm
>at all and wasn't very comfortable with 2mm whereas 1 was great . I think I
>have been off base with this diviation thing as I should't have been
>worrying about  the max allowed but instead worrying about what works for
>me. I measured about 50 of the slides I have sent around in past follios
>and all were less than1.2mm and most under 1mm and I have yet to have anyone
>tell me they are flat. I never did like the ping pong stereo often found in
>stereo movies . I find it boring and totally unneccessary. Has anyone seen
>any of my flat stereos ?? Sometimes I get some large deviations in my wide
>base hypers ,usually because something appears in the view which I didnt see
>in the viewfinder -just careless ! Don.

Final answer:

  I measured one of Don's slides (from "my"
slide folio) last night. It is a wonderful
shot with Mt. Rainier in the background,
a very smooth lake in the mid-ground and
the lake shore in the foreground.

  Don has it mounted "to the window"
but measurements show that it only has
about 1.5mm of On-Film Deviation. So
yes, you are measuring it the same as
everyone else.

  The slide is lovely and has plenty of
depth off to infinity without the painted
backdrop look that sometimes happens.
So I'll agree that 1 or 1.5mm of OFD (in
MF stereo) can make a completely satisfactory
slide. And everyone who's seen Don's
shots will attest to their depth and
beauty.

  My one question for Don is how you
avoid getting too much foreground in
your shots?  Especially when you shoot
with wide angle lenses?  Do you use an
extra tall tripod?  Shoot from the top of
your rangerover like Ansel Adams did?
Or what?

---

  My own reduced OFD story relates to
my 3d fireworks shots. I have one shot
taken with 8 foot separation where the
fireworks were over 500 but less than
1000' away. Let's call it 800'.  This
means that the near point is 100 times
the camera separation. So they have, at
best, 1/3rd of the OFD that you'd get
with a 30x camera separation shot.

  But everyone loves this photo. Several
have even said it is the best 3d fireworks
photo they've _ever_ seen.  So reduced
OFD shots can work.

  One trick, I suspect, is to mount them
just behind the stereo window rather than
with the proper infinity spacing. That
way you don't have a huge depth gap between
the 7' distance of the stereo window and
the 20 or 30' distance of the near point
of your image.

Greg E.