The front of a pinhole camera needs to be only the size of the hole. There is a cone of light with the pinhole the apex. So make the front as small as you like.
Couple of things. You are thinking of a wide format. Panorama pinhole cameras have some basic problems. First of all the light spread. If you think of the hole as a circle at some angle away from the center axis that circle is an ellipse letting in less than half the light of the center. This means that if you place the back-where your photo paper negative goes--too close to the front you'll just get a small circle of image in the middle of a large blank piece of paper. You need to keep the back some distance from the front. What distance? Some light fall off is acceptable, and even disireable, with pinhole images, so it is to a large degree subjective. I would recomend making two boxes slide into each other so that you can experiment with distance. If I had to crank out a large pinhole camera in the next hour and take a picture with it I would probably make the hole-film distance the same as the diagonal of the film. 7x17? 7^2 + 17^2 = Focal Length^2 I had some minor success back in college with a pinhole I called the Whatlux that was based on I think a 6" curve with the neg being a 4x10" sheet of paper curved around the back. I think it would have been more succesful 5x8 But my reasoning was that the ellipse effect (light falloff) was compensated to some degree with the outer sides of the negative being closer to the hole (inverse square law) Will ---William Nettles [EMAIL PROTECTED] Nettles Photo / Imaging Site http://www.wgn.net/~nettles > From: [EMAIL PROTECTED] > Reply-To: [EMAIL PROTECTED] > Date: Tue, 25 Dec 2001 12:08:29 -0700 > To: [EMAIL PROTECTED] > Subject: Cameramakers digest, Vol 1 #289 - 2 msgs > > Hi there: > I am planning on building an pinhole camera that shoots on 7x17" or 8x20" > paper. > It will be built out of wood with no bellows. Can you give me any > suggestions on > size of my front standard? I know it probably doesn't have to be huge, and > of course the smaller it can be > the less the whole thing will weigh. > I was also thinking of using a design similar to a "postcard cameras". > There will be a compartment for paper under the camera which is light tight > for paper that is already exposed, > and a sleeve that I can put my arm into that goes to the back of the camera > so I can move the exposed paper below, and shuffle > the next paper to be exposed into position. > Thanks in advance for your advice ! > Sincerely, > John _______________________________________________ Cameramakers mailing list [EMAIL PROTECTED] http://rmp.opusis.com/mailman/listinfo/cameramakers
