Summary

This is a pinhole "lens," designed to fit on a Canon EF or EF-S mount camera. The pinhole is not included — you'll need to punch a hole in some thick paper or thin metal, and slide it into the slot.

How I Designed This

Initially, I designed the front and base parts of the cap, separating them in order to create a slot where I could insert a piece of metal with the pinhole punched into it. The base had slots on the back which were intended to fit tabs on the mount piece.

I eventually added a space in the front of the front piece to accommodate a small red ring for that L-series look, and redesigned the connection of the back piece to use an additional ring which fits snugly with both the base and the back. I made this change in order to ensure that the back of the cap fit on the camera in a good-looking way (it had previously been too small), and that all the pieces could be printed without supports, and yet fit into each other in a vertical stack.

Assembly Instructions

Push the red ring into its slot on the front of the front piece.
Slide the front piece into its slot on top of the base.
Push the base onto the connecting ring.
Push the mount into the back of the connecting ring.

Find a thick piece of paper or thin piece of metal, and cut according to the shape of the slot between the front and base. You can also adjust the model to accommodate the thickness and size of your insert. Punch a pinhole into the center of the circular part at the end, and slide it in. For this component, I cut a strip from a sheet of copper flashing.

To get these pieces to fit together, you may need to apply a bit of judicious rubber-malleting. I don't recommend shaving off or sanding plastic, since you won't want that dust in your camera. In theory, everything should fit, and might fit better if you print more precisely than I did.

Pinhole "Lens" (EF/EF-S)