Re: [photo-3d] Stereo Camera Builders - Attention!

["John A. Rupkalvis" <stereoscope@xxxxxxxxxxxxx>]

----- Original Message -----
From: "David Lee" <koganlee@xxxxxxxxxxxxx>
To: <MF3D.Forum@xxxxxxxxxxxxx>; <photo-3d@xxxxxxxxxxxxxxx>
Sent: Monday, February 26, 2001 9:29 PM
Subject: [photo-3d] Stereo Camera Builders - Attention!


> Those who build or are interested in building stereo cameras might be
> interested...

 Although I am not currently building any 4x5 cameras, you may be interested
in some things that I have done in the past.

Sinar made some interesting bellows configurations that were quite useful
for stereo.  One was even dual chambered.

I usually would mount lenses in barrels to lens boards, as these were
smaller in diameter than when mounted in conventional leaf shutters.  Then I
would either use a focal plane shutter (ala Graflex), or a single
behind-the-lens guillotine type shutter that would travel past both lenses
simultaneously.  These can be homemade, are reasonably simple (either single
or dual blade), and solve the problem of synchronism.  They can be gravity
drop type for slow shutter speeds, and spring augmented for higher.  If you
want to get fancy, they can be solenoid operated.  And, since the blades are
so large, it is easy to mount contacts on the edge outside of the image area
for flash sync.

Figuring 150mm to 180mm as being "normal" 4x5 lenses, 120mm is not too bad
for stereo, many subjects of which benefit from a slightly shorter focal
length.  I actually prefer even wider angles myself, and used to use a pair
of 100mm Schneider Super Angulons for many subjects, although I did a few
scenic hyper views with a single camera and a 360mm Symmar, which is a
fabulous high resolution lens.

If you really want some interesting "effect" stereo shots on 4x5, the widest
angle lens that I am aware of that will cover the film size, was the 58mm
Grandagon.  It required a special bellows (actually a single flute, looking
like a bag) to allow the lens close enough to infinity focus on the film
plane.  It just barely covered the film, with no shifts, swings, or tilts.
With cameras like the Sinar, the Calumet, and probably most others, you had
to reverse one of the standards to get them close enough together to focus.
Amazingly, it had very little distortion.  There was some light falloff away
from the center, but the Schneider center filter for the Angulons worked
very well with the Grandagon (Rodenstock) as well.  Anyway, the results in
stereo with most subjects were wild, if you are into that sort of thing.

Incidentally, before the turn of the second previous century (it used to be
easier to say "turn of the century"), only cameras larger than 8x10 were
called "large" format, 8x10's were medium format, 5x7's were called "split"
format, and 4x5's were "small" format, or sometimes "Quad" format, from an
8x10 plate being quartered - you got 4 plates from one 8x10, if you were
handy with a glass cutter in the dark.  Things change.

Wish you the best in your project.  I hope that I have the time and money to
get back into large format someday.

JR



 

Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/