Building a TtV cannon
Tuesday, January 9th, 2007As discussed in the previous post, an important part of shooting TtV is building a usable contraption. The crucial purpose is simply to block the light (and thus any unwanted glare or reflections) when shooting between top and bottom cameras. There are many fine box or tube style contraptions out there for connecting to unmodified bottom cameras. To put one together you just have to find some kind of tube like material of approximately the right diameter to work with. I scrounged around for a while and came up with the idea to use cardboard postal shipping tubes. After trying out various ways for cutting and notching the tube to fit over my bottom camera I opted to go a completely different route (influenced by what people were doing over at the sPiNoFF! Group). Instead of keeping the bottom camera intact, I decided to remove the glass elements completely from the bottom camera, in this case a Kodak Duaflex IV and build a homebrew cannon style “lens” to hold them.
The idea was to get two different size postal tubes that would fit inside of each other, a 2 1/2″ and a 3″ diameter tube would do the trick. Then cut holes to mount the glass elements from the Duaflex in the plastic end caps that fit the tubes, so I could switch glass as easy as popping in a new end cap. The back element (bubble) pops into an end of the 2 1/2″ tube, the other end of this tube jams snugly into the lens hood that fits the pentax kit lens. Then the front element (objective lens) mounts into the 3″ tube, which slides over the 2 1/2″ tube. There would be a consistent 1/8″ gap between the tubes which I figured I would fill by wrapping black felt around the end of the inner tube to block light and tighten up the telescoping action.
But before we can get to all that, we have to dig the glass out of the Duaflex























