[MF3D.FORUM:620] Re: Dual Cameras

["Stuart Johnson - GCSPHOTO" <GCSPHOTO@xxxxxxxxxxxxx>]

Bill Writes:

    > The chart below shows the reasons why I fell this way.  Below
> is John B's formula with an 80mm lens and a constant 2.7mm factor.  As you
> can see, the shot selection is very limited with a stereo base a min. of
> 6.5" and a max. on the stereo bar of 22".   For example, a 10 ft. near
would
> (which is not that close for a normal lens) allows for a max. of 26 ft.
far.
> That seems very limiting to me.
>          I am using a Jaspar engineering 24" stereo bar... the 6.5" min.
> inter ocular lens spacing is a result of the camera bodies being too big.
> Why do you recommend going to 50 or 60mm, vs. a normal 80mm?

Bill,  I have shot almost exclusively in 24, 28, and 35mm  in ---35mm
cameras---
(this would be about 40mm to 50mm in a Medium format) and immediately
discovered that I had a
lot more composition flexibility and oppurtunity to have more Near-Mid-Far
distant object oppurtinities as well. Especially in close conditions.  I
shoot
so that EVERYTHING (including infinity) is in focus and I never 'toe-in' to
avoid
Keystoning.  Just make sure the two cameras are parralel and check to see
what
the center focusing rings are pointing at (left camera center image should
appear more left of the
center of the image on the right camera in the distance  -always!).  I don't
have the baseline formula
handy, but it seems to me that the wider the lens is, the shorter the
distance to the near
object can be as well.   Again,  it is my firm belief that the technical
advantages of
shooting with two cameras SIMULTANEOUSLY regardless of the Stere Base is far
more important than almost anything else regarding one with a slide bar.
But that
does not mean that you can ignore or lessen the concern of the stereobase
with the dual cameras either.  To be honest, I basically decide what is
acceptable for
a minimum seperation between lens and near point of the picture, set it at
f-11 to f-16,
focus in on near to mid points (infinity comes in clear naturally at the
stopped down
apertures mostly anyway), and concentrate more on my composition.... The
rest of the
stuff just comes naturally (like clean glass, fresh batteries, focusing,
film settings, alignment,
etc...)  You might want to just start shooting a lot FIRST with some basic
understanding and THEN get into
the more technical stuff later.
Remeber:  A lot of stuff is technically "perfectly executed" -Yet, rates LOW
on the
interest and artistic level...

    Get out and take lots of pictures Bill, ....In time (along with all
these forums) I think you'll soon
become very comfortable.  I have a long way to go "technically", but am
really enjoying the
challenge of capturing a great shot (when I am lucky to come across one) in
the meantime!

-Stuart