I'm truly confused. I just built a tube out of two cylinders, 27" long and .66" in diameter, shaded it chrome, put a conical camera 8" inside the tube, put a spot at a slight angle at the far end of the tube, and rendered the attached. Is this not what you are trying to do?

The only problem I ran into was that I couldn't illuminate the inside of the tube very well, but I think that's a matter of finding the "sweet spot" for the general light. I tried putting a spot and then a bulb "inside" the tube, and neither had any effect, but I'm guessing I didn't get their centers exactly inside.

Two other problems, which I found when I started fiddling with animation: 2. Image-based textures can't deal with this kind of close scrutiny. I put a "wall" at the end of the tube and when the camera arrive, the wall's texture was grossly pixelated. But that's to be expected if the camera moves in too close.

2. You do have to Zoom the camera to get the viewfinder entirely inside the tube. Under my original light conditions, I didn't know I could "see" outside the tube. When I added the wall, I noticed a "viewfinder" box at the center of my image, and moving to 200mm made it go away.

Theoretically, I should be able to reduce the tube diameter to .06" and still "see" down it, because the camera is a polar point. As long as I get that exact point inside the tube, the camera can see. I just tried .06" and I can still see inside the tube. I also tried animating the camera to run the length of the tube, and that worked.

Am I missing something here?
M