While making enhancements to the “Sohdo” Long time-lapse device at Innovo, while 3d-printing a camera mount for final pre-production refinements. We had a little time. A friend there was showing me a new PCB milling machine, and I saw that it had very thin drill bits; the thinnest was 0.3mm (300 microns). So I had the idea of doing a “clean” pinhole. So we followed these steps.
Usually, to locate a center I would go spinning the subject. I fix a fine tipped object (the best is a pencil) and make it draw a circle; I adjust the pencil position until the circle becomes a point. We had nothing that could rotate, so we sought another fix.We precisely measured the circle on the back of the cap. On a hobby CNC we routed a gap in which the cap fit tightly.
The cap was thick, so we opted to have the pinhole on a thin sheet. That needed to have the plastic cap even in surface so we “de-Nikonized” it. We drilled a relatively big center hole, and did engraving in which the thin metal sheet would be inserted. And that also helped in preventing any eventual light leak.
Then we used PCB milling machine to drill the 0.3mm hole in the center of the sheet which was cut in a circle that fits the previous engraving of the plastic cap.
Actually I did two circular sheets, one with a pinhole of 0.3mm and the other with a 0.6mm hole.
I took few test shots and saw what were the flaws of the current process.
The sheet should be very thin, and the one I used was 1.3mm, so heavy vignette occurred on the 0.3mm pinhole. I made a 0.3mm pinhole on a 0.5mm metal sheet in which the above time-lapse video was shot. vignette has gone. The video a bit color processed and not deflickered (I am now more sure that most of the flicker is due to un-precise apertures.)
I found this calculator to be very useful
and here are some quick test samples, hoping to make a decent pinhole timelapse very soon…forget not to have your sensors very very clean. and remember to close the viewfinder if going for long exposures.
Register below, and stay updated
You can always find more information at www.alexfr.org
or join the facebook page Alexy Joffre Frangieh
or follow on instagram alexyfrangieh