DIY Pinhole Lens

This is a simple pinhole lens with a built-in shutter, meant for a DIY pinhole camera build. It will cover anything from 35mm to 8x10 large format. The pinhole is 0.3mm in diameter, resulting in an aperture of f/256. It has four counter-sunk mounting holes, 4mm in diameter, which can be used to affix the lens to a wooden or cardboard camera body, using either bolts or screws. Its rear flange is 36mm in diameter, and protrudes 3mm out to prevent light leaks when mounted to a camera. The lens has a focal length of about 67mm. 

For exposure on 100 iso film, use an exposure time of about 4 seconds in daylight, 30 seconds on an overcast day, and 30 minutes for a home interior. These exposure times can be reduced by using a higher iso film. For exposure on photo paper, these exposure times should be multiplied by 5 (i.e. 20 seconds for a photo in daylight). For longer exposure times, reciprocity failure compensation should be incorporated into the exposure length calculation.

Printing and Assembly Instructions

1. Print on each of the lens, shutter, and retaining plate. The lens should use supports under the overhangs, but the other parts don't need supports. The recommended print settings are 0.10mm layer height, 3 wall perimeters, and 20% rectilinear infill. This should take about 1.5 hours, and use about 18 grams of filament.

2. Remove the supports with the help of a pick tool. 

3. Cut the pinhole plate from an aluminium soda can. The plate should be square, with an edge length of 20mm.

4. Place the pinhole plate into the square cutout of the interior of the lens. The retaining plate can then be placed over the top of the pinhole plate to hold in in place. This is a friction fit, so a small amount of force is needed here. Some superglue around the edge of the pinhole plate (where it meets the inner ring of the retaining ring) will help prevent any movement of the plate. If the retaining plate is loose, superglue can be used to ensure it doesn't fall out.

5. The inside of the lens should now be painted black with spray paint. This is optional, but will result in less artifacts in the image.

6. Drill the hole in the lens plate using a wire-gauge drill (twist drill) with a diameter of 0.3mm. These types of small drill bits can be found on Amazon. Alternatively, use a small sewing needle to puncture a hole in the plate. This will result in a hole diameter of about 0.5mm, which will produce a wider image, although not as sharp. 

7. Insert the shutter into the lens until it clicks into place. It should now be able to open and close, without falling out of the lens.