Tim Stabler - stereo with a mono camera

[P3D John Bercovitz <bercov@xxxxxxxxxx>]

Tim Stabler wrote:
 
> Lastly, what do you use for a bar for taking stereo shots with 
> one camera??  I am an old 2-d person with a Nikon n90s I would 
> like to do some macro work with.  But, if I get the chance to 
> return to the state of Washington and Mount St. Helens, I might 
> like to try scenics also.
 
Your post had quite a number of topics in it.  Yuh gotta remember 
this is short-attention-span theater for some of us.  8-)  I 
didn't see this, your last question, until today.
 
Of course the simplest method is to shift your weight from one 
foot to the other between shots.  This gives you approximately 
the correct stereobase.  But you asked about slide bars.
 
I made my longest one from the slide mechanism inside of a copier.  
Just screwed a plate under it so as to have a place to attach the 
tripod and a plate on top so as to have a place to attach the 
camera.  It can do up to 43 cm.
 
I made one from ground steel plate which slides in brass grooves.  
I have that one adjusted to match my own IPD.
 
I've also made two from commercial single-axis slides someone gave 
me.  This style would be particularly good for macro because it 
has a scale on it and a crank to do fine adjustments.
 
I think if I didn't have any real tools, I would go with a simple 
design from one of the books on 3D ("World of 3D"?).  You make a 
wooden block to attach the camera to and a wooden tray to slide 
the block in.  The tray is wider than the block by the desired 
stereobase.  The tray is what you attach the tripod to.  (Or vice 
versa if you prefer.  8-)
 
         _______________
        |               |
        |               |
        |               |
        |       O       |   block with camera attachment hole
        |               |
        |               |
        |_______________|
 
 
                        |<-----stereobase---->|
 
 _____  ______________________________________  _____
|     |                                        |     |
|     |                                        |     |
|     |                                        |     |
|     |                                        |     |
|     |                                        |     |
|     |                                        |     |
|     |________________________________________|     |
|                                                    |
|                                                    |
|____________________________________________________|
 
 
You can add width to the block for macros.  (Or subtract width 
from the tray.)
 
You may wish to consider doing hypers for scenics.  If the scenes 
are of distant objects such as mountains, you won't get much 
stereo.  So you take the two shots with an enormous stereo base 
and then when you view the result you will have a tiny scale model 
of the original scene and you will be able to see these large, 
distant objects in 3D.
 
John B
 


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