Twin 35

[P3D <JNorman805@xxxxxxx>]

    I've seen a lot of postings about synchronization of twinned cameras,
interocular distance,  vertical format, hyperstereo, etc., so I thought I'd
weight in with my own experience.  
    I use a pair of Canon EOS Rebel X 35s, mounted vertically, bottom to
bottom by their tripod sockets, fitted with 35-80 zoom lenses.  The lenses
are autofocus, so they focus together as loong as they are not confused by
differences in depth by different perceived subjects.  I rely on
auto-exposure, aperture priority, and I've never had any differences in
exposure from camera to camera.  I have them rigged to zoom together with a
system of home-made gears, industrial toothed belting and a large rubber
band.  (I've never had a problem with differing focal lengths with this
system.)  They fire simultaneously via two remote electrical cable releases
spiced into one button.  There is no apparent need for a "black box."  Unless
the two camera's perceive different subjects, as sometimes happens when I'm
too close, and one camera or the other tries to "hunt" for focus, the sync is
absolutely reliable. (Flags flapping in the wind, waves on the water, etc.
are all perfect).  When I hook a Vivitar 285 flash via a remote sensor cord
to one camera, the synch between the two cameras is reliable enough to get
perfect flash coverage about 90 percent of the time.  (Haven't figure out
what causes the problem the other 10 percent of the time, but I live with the
odds.)  The interocular distance is 3 3/8 inches, so my camera-to-foreground
distance is about 8 feet.  I'm limited to vertical formats, but for most
subjects that's not an onerous limitation.  I find that my most frequent use
for horizontal format is for landscapes and such, and a twin rig is useless
for such distant shots anyway.  For them, I use a single camera, separate
hyperstereo shots.  Generally, I just try to remember what's in the
viewfinder, note my shooting position, and concentrate on replicating the
same scene as many feet away as I feel I need for the particular situation.
 Seems to have worked out pretty well so far.   Just my 2 cents worth, and I
hope it's useful to others.
                                                                      Jim
Norman   


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