Twin Camera Rig, Construction details

[Mark_Poole@xxxxxxxxxxxxxxxxxxxx (Mark Poole)]

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     Here are the details of my homebuilt hyperstereo twin camera rig.
     
     I have been bouncing this idea around for a good 6 months or so, 
     but only this weekend did I get some free time while my wife was 
     out "saving money" at all the pre-Christmas sales.
     
     To begin, the following is a wish list of what I wanted: 
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     Light as a feather.
     Be able to go from as-close-as-possible to six feet of separation 
     or more. 
     Interchangeable length bars.
     No unintentional yaw of camera orientation. 
     Rock steady.
     Solid construction; can stand a few knocks.
     Be able to flip camera 90 degrees for vertical format.
     Break down in moments, toss into a backpack, and reassemble on 
     mountain peak or inside a cave.
     Look better than my storm door rig.
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     I have a Bogen tripod intended for video use. It has bubble levels 
     for two axes.  This bugger is cool, looks professional and is 
     _heavy_. But it is a solid platform for the rest of the rig.  I 
     have a little carbon fiber jobbie, but it sags at the sight of the  
     twin Minoltas (7000i with 35 to 70 zoom autofocus lenses).
     
     What I did was obtain a couple of different lengths of 1" square 
     aluminum tubing.  This is heavy-duty stuff, not paper thin.
     I have a 1' length for the close-as-possible only (inside shots). I 
     have a three footer for the hyper shots.  I will test these and 
     probably go to six and maybe even eight feet.  I am limited to what 
     the bars will support and what will fit into my car (of course, I 
     could get a roof rack...).
     
     I then built three "carriages" or boxes that fit almost snug to the 
     bar.  One carriage fits on the tripod and is almost square.  The 
     other two carry the cameras and slave units for my infrared synch 
     rig.
     
     These were all made from a few scraps of 3/4" plywood. I "glued & 
     screwed" them together with waterproof epoxy and ceramic coated 
     square-drive screws.  Why? Because I had all this stuff laying 
     around my workshop and it pays to be careful with camera equipment. 
      I have lost a flash and a zoom lens to improperly secured 
     equipment (not while doing stereo).  I can't afford to have this 
     stuff to fall apart after a brief exposure to moisture.
     
     The camera carriages are about 5 inches long.  With this length, 
     they don't rattle about on the bar.
     
     I will be using steel 1/4" x 20 threaded inserts in all of the 
     carriages.  I have found these little black knobs with that size & 
     thread count for 75 cents each.  I will use the knobs to lock the 
     carriages along the bar. The tripod mount will have two threaded 
     inserts.  One to lock the bar in place, and one to secure it to the 
     tripod.  I have also glued a piece of sandpaper to the plywood 
     block so it will grip the tripod head securely.
     
     I will paint all exposed wood with a couple of coats of 
     outdoor-grade Krylon. I will probably use black, so it will match 
     the rest of my gear.
     
     On the camera slides, I have mounted (glued & screwed again) these 
     plastic dohickies that were designed to allow you to flip the 
     camera 90 degrees if you didn't have that sort of feature for your 
     tripod.  These are so I can get a vertical orientation for 
     waterfalls and other tall stuff.  I have used these before, in fact 
     I cannibalized them off my previous rig.  They are made out of a 
     durable black plastic and cost about $6.00/each.  I got them at 
     Ritz camera a couple of years back.
     
     The whole thing looks impressive, in a heavy-handed kind of way.  
     The mounts are solid now, unlike my previous rig.  I can put any 
     length (within reason) of 1" square aluminum tubing in it.  I can 
     change out tubes quickly and easily.  The drawback this shares with 
     other twins in this configuration, is that even at their closest, 
     the lenses are still a good 4" apart.  This gives me 12' to nearest 
     object if I follow the 1/30 rule.
     
     I think I met most of my design requirements except the "light as a 
     feather" part. If I had more money, or access to metalworking 
     instead of woodworking tools, I would have fabricated all of the 
     parts from aluminum stock.  I might save a pound of weight or two 
     that way.
     
     I can't wait to get out there and try some hyper shots.  I live 
     near the Blue Ridge mountains, so I have access to Parkway 
     overlooks of some super scenic views.
     
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     Mark Poole               |  Mark_Poole@xxxxxxxxxxxxxxxxxxxx 
     The ants find kingdoms in a foot of ground -William Rose Benet 
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