One Sheet; One Shot!
The terraPin Box Turtle is designed for 4X5 sheet film or photographic paper and consists of only four 3Dprinted parts. The front and back halves slide together to sandwich a sheet of film 75 mm (or 35mm) from the pinhole. The shutter is designed around four (4) rare earth magnets, 8mm x 3mm, that hold the shutter in place and work as pivot points when snapping the shutter open or closed. Behind the shutter, the pinhole is mounted with a locking cam-clamp.
All photos by Moni Smith using either Fujifilm Neopan Acros 100 B&W film, or Kodak Ektar color negative film.
Expanded information and instructions coming soon!
Box Turtle 75
focal length 75 mm
pinhole 0.30 mm diameter
Box Turtle 35
focal length 35mm
pinhole 0.20 mm diameter
Photos are of early prototype, STLs differ in detail.
- Added 35mm wide angle version
- Revised shutter and pinhole_clamp to work with both 75 and 35mm versions
- Added some light-trapping to front of camera, to minimize light leaks from box joint.
- Added small indexing pips to hold pinhole_clamp in position w/o glue
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0.25 mm / layer as printed
- four (4) rare earth magnets, 8mm x 3mm
- pinhole 0.30 mm diameter for 75mm Box Turtle; 0.20 mm for 35mm version
- 1/4-20 flanged nut for tripod nut
- epoxy for mounting magnets and tripod nut
- Super Glue or other Cyanoacrylate glue for mounting pinhole and locking pinhole_clamp
- Magic Marker / Sharpie for blackening backside of pinhole, magnets in body
- flat black paint for reducing reflections if your filament is shiny. Cheap insurance.
Use a razor to shave off any ridges from tape on the hot bed. Especially around the pinhole/shutter area. You want the shutter to sit absolutely flat on the front of the camera.
The location of the magnets should be obvious. Orient them the same at both ends, so that it doesn't matter if the shutter blade is upside-down or rightside-up.
The "pinhole_clamp" is a clever bit of snap-fit joinery that twists into position to hold the pinhole against the back of the front half. Carefully secure the pinhole on the clamp with some Super Glue. The clamp will only go on one way. It rotates counter-clockwise to lock. Two tiny nubbins stand proud to lock the clamp in position. You should be able to pop it free if you want to monkey with your aperture. See photo.
The fit of the two halves is snug, Open and close the sliding joint slowly to avoid damaging your pinhole. It will work looser with a little use.
After adding the light trapping around the lip of the front, the two halves will only slide together properly in one configuration. The tripod nut on the bottom of the BACK will be opposite the thing:2206746 lettering on the top of the FRONT. These surface features can be discerned by touch in a changing bag.
Simple tools work great!
I designed this camera to be used for generations. I could have made it much flimsier, but I believe that tools need to be robust and durable. It should withstand a fall to the floor and other hazards. I designed it 100% in Tinkercad. Took me a couple hours total design time with a few revisions. Try it, if you haven't!