View Full Version : two paper halfrounds

04-21-2005, 06:11 PM
small for 9x13, focal length 47 mm, 0,25,mm, f 188
tall for 13x18, focal length 49 mm, 0,26 mm, f 188

making was fun! : :)
front Attached files http://f295.f295.org/uploads/front_6654.jpg (http://f295.f295.org/uploads/front_6654.jpg)

04-21-2005, 06:12 PM

Attached files http://f295.f295.org/uploads/backside_1419.jpg (http://f295.f295.org/uploads/backside_1419.jpg)

04-21-2005, 06:12 PM

Attached files http://f295.f295.org/uploads/open_3277.jpg (http://f295.f295.org/uploads/open_3277.jpg)

04-21-2005, 08:55 PM
Thanks for showing these cameras, bino. They give me some good ideas. I have been limiting my curved film plane designs to objects that are already cylindrical - cans and boxes. I like the idea of pure construction, and the idea of putting the pinhole on a flat side. Nice work.

04-22-2005, 08:17 AM
Here's an idea. Make the camera triangular instead of cylinder. The curvature of the film plan would be variable and determined by the width of the negative.


04-22-2005, 08:38 AM
I make this one: hole A on one edge, paper over the other edge
cut it at the red line and make the hole in a frontplate at the red line?
Have I understand you? :) Attached files http://f295.f295.org/uploads/kldo3l_6469.jpg (http://f295.f295.org/uploads/kldo3l_6469.jpg)

04-22-2005, 10:26 PM
Gary: this looks like what you suggested - a triangular camera. Our church is holding a huge 'Trash and Treasure' sale right now, and there are about 3 dozen tins of various sizes and shapes. I bought one today for $.25 - a cylinder 7.25" high by 6.5" dia. (18 cm x 16 cm dia). Maybe I will grab a couple more of different shapes tomorrow.

04-23-2005, 10:17 AM
My first thought was figure A. Different curves result by varying the width of the paper. Unfortunately that would also vary the resulting f/ making exposures unpredictable. In a camera like figure B, a single width paper (or negative) is used in any of the three positions. The f/, focal length, and exposure time for each of the three positions can be worked out. I'll leave it up to you guys to work out the details of size, materials,etc.

Gary Attached files http://f295.f295.org/uploads/triangle_2905.gif (http://f295.f295.org/uploads/triangle_2905.gif)

04-23-2005, 10:33 AM
Interesting idea, ElrodCod. Thank you. I will think about it.
Maybe some day.... :)