P3D ISO Super Duplex - Questions

["Dr. George A. Themelis" <DrT-3d@xxxxxxxxxxxxxxxxxxxxxxxxxxx>]

My new ISO Duplex Super 120 arrived yesterday!  I had already
ordered 120 film from B&H and I am trying it right now.  For
those not familiar with the camera, it was made by ISO (Industria
Scientifica Ottica, Milan, Italy) around 1965.  It has two
35 mm lenses spaced only 30 mm apart, which makes it a good
choice for close-ups.  It has aperture and shutter speed control,
x-synch for flash and focuses down to 1 m (3 feet).  That's not
close enough but people have used close up lenses with it.
It takes 120 film (medium format, not 35 mm) and puts the two
images next to each other in the vertical side (that's why the
lenses need to be spaced 30 mm apart).

It's a cute little camera.  Very expensive to buy and nowhere near
the construction quality of the Realist but the narrow spacing
of the lenses is the big attraction here.  In my mind, it is better
than an unmodified Nimslo which eats film, gives 4p images and
has no aperture/speed/focusing control.  The ISO gives Realist-
format images (23x24 mm)

Questions:  How many pairs should I expect to get from the 120
roll?  Do I advance frame after frame as they are marked in the
film? (there are two windows you can read the back of the film)
I just shot one roll and got 12 pairs.  Does that sound right?

Seems that the aperture is controlled by a square aperture
blade.  This does not seem right because it is off-center and 
never too small for say f16.  I suspect that there should be
another blade.  The two blades should define a square. But
my camera only has one.  Can anyone verify how is the aperture 
controlled?

Thank you! -- George Themelis

PS.  There is another ISO camera, the Duplex 120 (not "Super")
This one has 25 mm lenses and fixed focus.


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