Author, very fine set-up and the sepia adds to the effect, but the image appears to suffer from a bit of over-sharpening, resulting in a great deal of Jpeg artifacts. All-in-all, a very nice job in a hard contest...Bravo

By your SBS author...I see the focus problem here, Nice attempt, but there is either too much material making the hole deeper than it needs to be, or the hole is entirely too large. A very tiny hole increases the DOF to nearly infinity by giving an effective f/stop of about f/88-f/176

I know what you mean, I have tried some more and will upload one later, but I still can't get them sharp. despite having a much thinner material and a minuscule hole.
On a bright day I'm having exposures of 6-8sec at ISO 200, so I'm sure my hole is very small. Just a careful pin prick.

Author, to get rid of the vignette, try shortening the tube a bit to allow more of the image to fall on the sensor. Also, take sandpaper (very fine) to hone the edges of the tube at the cut-off end. It appears your 'lens' or hole is very jagged...try re doing the hole with a fine sewing needle very carefully as irregularities will result in poor focus...GL