We sent the interns to Home Depot and they came back with a door viewer from Schlage. It cost $9.46. I'm not sure why I didn't get any change for the $20... something about a double venti something. Anyway, this one does not appear to be as large in diameter as the one used by Slacy. The diameter of the hole is 9/16", but it does claim a 190º view!
Sure enough, just shooting through the barrel of the viewer works pretty well. You do have to hold it against the lens and it does move around a bit. The shot was taken using the same Canon S100 used for the macro shots. Click on the image to see it in full resolution. We'll show you how to rig up a slip-on mount so the lens will be easier to use.
We knew there was a reason why we saved those 35mm slide canisters! They are just right as a mount for the wide angle lens :-) The fit is not perfect, but a little cutting here, a little padding there... it will fit just right.
The first step is to cut out the center of the cap so the lens can be mounted. The easiest way is to first cut an X, next remove the flaps, then thread and mount the lens.
When the lens is mounted, it should be gripping the cap from both sides and not move around at all. The silicone or rubber pieces will the be placed in the cylinder to grip the camera's lens.
The only thing remaining is to cut off the end so the entire rig can be slipped onto the camera's lens.
We measured the distance the camera's lens protrudes in max telephoto mode and cut the end so the end of the wide angle lens is just touching the camera's lens.
We added two silicone pads (red arrows) inside the canister so the whole thing would stay on the camera without us having to hold it. We decided to mount the wide angle lens on the cap because we had this grand vision of being able to swap different lens onto cylinder.
Some work is still needed to get the distance just right so the camera's lens wil sit flat against the wide angle lens. Also take care NOT to shut off the camera before removing the cylinder. In our case, the grip was strong enough that it prevented the lens from retracting into the camera... which could potentially damage the auto focusing mechanism.