On Thu, 13 Jun 2002, John Carmichael wrote: > Problem solved! > > Mac Oglesby just solved the image ellipse problem that I had with the > pinhole sharpener when the sun is low. I had been holding my sharpener > perpendicular to the sun's rays which produces an elongated image of an > ellipse around sunrise and sunset. He said that if I hold the sharpener > parallel to the ground, that the image becomes round. I didn't believe him > and thought it impossible, but both Edley and I just tested it and Mac's > right! Although as Edley noted to me, the image is dimmer, but that's no > problem.(Using some tilting of the planes because its midday here). > > Thanks Mac! > > John
One important consideration here is to make the pinhole in as thin as possible a sheet of material. Foil stretched over a hoop would work well, and be easy to punch. Pinhole camera buffs make a point (heh!) of drilling a hole, using a sharp needle, with a backup block of plastic or the like, to ensure a smooth, burr-free hole. Then polish both sides with very fine emory cloth. For these shadow sharpeners, I doubt that's all necessary, but a "flat" hole in thin stock would be best for you, too... Dave 37.29N 121.97W -
