First mockup prints for testing the removable insert and the winder/clutch/knobs.
Viewfinder added and modified body cover for it.
Caution, the initially provided knobs do not fit - I replaced them with a new version with now hopefully fitting measurements.
Tripod Plate added.
Redesign of my 6x12 pinhole camera with curved film plane based on first real world tests.
This redesign is currently untested but I am quite confident that it will work without problems.
I kept most of the basic specs and design principles:
==> using roll film type 120
==> format 6x12 (exposed film area is 56x116) with curved film plane
==> 65mm focal length
==> pinhole diameter 0.3mm
==> resulting aperture about f/215
==> shutter as separate module, exchangable
==> no light seals necessary
==> Arca Swiss compatible tripod plate
==> compact & lightweight
Based on the tests with the initial prototype, I decided to design a removable film insert.
==> easier film loading
==> film guides can be polished
Using a removable film insert required a complete redesign of the knobs/winders.
The curved film plane causes a lot of friction between film and the film guides, so film advancing required some power and resulted in unhealthy torsion of the flat winders.
Now there are the inner winder which stay at the film insert top plate and there are the outer winders with the knobs which stay at the body cover and connect to the inner winder with a square clutch.
The shutter from the initial prototype proved to be quite usable, so I kept the basic design and just modified its base plate (now squared, allowing to have the wire trigger down, left or right). The vignetting problem from the initial version is solved (cone with larger base instead of cylindrical hole). Using a quite large shutter module base plate will allow different shutter designs and also the addition of a filter holder (not yet designed).
Simplification of the light traps between body and cover. Tolerances seem to be tight enough to give up on the inner light trap. Thus, closing should also become a little bit easier.
Currently missing pieces:
==> two sheet metal springs which press against the film and thus prevent the film to unroll. I won't make an extra design for this, because it's just a piece of sheet metal to be bend to form and screwed into the slot in the film insert
You will notice that I am working with quite tight tolerances, especially when you are printing with 0.2mm layers or larger. So be prepared to use sandpaper or a little file to make the parts fit together.
For me, this approach works better than parts wobbling around...
If you find any mistakes or misconceptions, please leave me a comment, so I can improve my designs.