Constructing a Pinhole Camera

Since two of my hobbies are woodworking and photography, I decided to combine them and build myself a wooden camera. By far the easiest camera to build is a pinhole camera, so I started there. I'd eventually like to build a working view camera, but since I've always been interested in pinhole camera, and it looked like I could build one in a weekend or two, I decided to design and construct a simple pinhole camera. Because I plan to eventually build a 4" X 5" view camera, it seemed obvious that the pinhole camera should use 4" X 5" sheet film and use standard sheet film holders.

Obviously, the most critical element of a good pinhole camera is a clean, round pinhole of the proper size for a given focal length. Here, I decided to take the easy route and purchased a set of micro drilled pinholes from the Pinhole Resource . These are drilled in 0.001" monel and the ones I received are very round and clean. From what I've read, the optimum pinhole diameter may be calculated from the following formula:

d = 0.00734 * sqrt( f )

where f is the focal length in inches, d is the diameter of the pinhole in inches and sqrt(f) is the square root of the focal length. My first camera has a focal length of 3.75" and from the formula, requires a pinhole of 0.0142" diameter. The set of pinholes from the Pinhole Resource included a pinhole of 0.0138" diameter, which is what I used in this camera. Aperture is simply focal length divided by lens diameter, which in this case is 3.75/0.0138 or f272. This is roughly 1/256 the amount of light produced by an aperture of f16. This means that, using the sunny 16 rule, in bright sunlight with ISO 100 speed film, the proper exposure is about 2.5 seconds. This exposure does not account for reciprocity, which varies with each type of film.

The 3.75" focal length is roughly equivalent to a normal lens. I also have build pinhole cameras with focal lengths of 1.5" and 6" to create wide angle and telephoto cameras respectively. (The 1.5" camera does have some vignetting around the corners, so a 2" focal length may be preferable.)

pin3.jpg

Four of my finished pinhole cameras may be seen above. The wide-angle pinhole camera in the front is fitted with a 6x6 film back made for 4x5 view cameras. These may be easily found used for $80 to $100. The camera in the center of the back row was build out of basswood and is finished with a clear salad bowl finish. This photo was taken with a pinhole camera, which has a focal length of 2.75" and a pinhole diameter of 0.0126" for an aperture of f218. Exposure was for about 3 seconds on TMAX 100 4X5 sheet film.


Materials


Tools Used


Disclaimer

This document describes the process I used to build a working pinhole camera. It is definitely not the easiest way to build a pinhole camera, but is simply what worked for me. If you are not familiar with the proper operation and safe use of the tools described in this document, don't even consider attempting this project. For example, if you don't know which direction to feed stock on a router table, stop now. Fingers don't grow back.

All the dimensions described in this document and included on the drawings are relative to the size of the film holders I bought and relative to the dimensions of the wood I had in my garage. If you change any materials, expect the other dimensions to change.

Read and understand the entire directions before you cut any wood. Also, purchase all of the materials before you begin, since you may not be able to find the exact same wood or hardware as I used and this will cause a change in the dimensions you use. You may want to change a dimension or two (particularly the depth of the 'lens' board rabbet) and you need to make these decisions before you start.

The pinhole camera described here is my first generation pinhole camera. I expect the design to evolve as I make new cameras and I will try to keep this updated. Please email me at lesweb@gehman.org with any ideas for improvements.


Directions

1) Cut two pieces for MDF that are 6" X 4-1/2" in size. These are the sides .

2) Cut one piece of MDF that is 5-9/16" X 4-1/2" in size. This is the bottom .

3) Cut one piece of MDF that is 5-9/16" X 3-3/4" in size. This is the top .

4) Cut a piece of 3/4" MDF 6-3/8" X 4-3/4" in size. This is the back of the camera, which is used to hold the film holder in place.

5) Cut one piece of 0.2" plywood 6" X 4-3/4" in size. This is your 'lens' board .

6) Adjust the router table such that it cuts a 3/8" deep rabbet which comes 3/8" into the wood. Two pieces cut this way should join together as shown in the back view of the pinhole camera.

7) Use this router table setting to rabbet the inside top and bottom edges of the two sides, and the two inside left and right edges of the top and bottom.

8) Use the same router table setting to rabbet the inside back edges of the side and bottom pieces.

9) Adjust the router table such that it now cuts the same depth of rabbet, but only comes in 0.2" into the wood.

10) Use this router table setting to cut the inside front edges of the top, bottom, and side pieces. This is the rabbet that your 'lens' board will fit into.

11) Adjust the router table such that it now cuts the same depth of rabbet, but comes in 3/4" into the wood.

12) Use this router table setting to cut the inside back edges of the sides and bottom. This is the rabbet that your film holder and back will fit into.

13) At this point the four pieces should fit together nicely to form a box. This is the body of your pinhole camera. If the pieces do not fit well, most likely you weren't careful enough in doing step 6.

14) Drill an 11/32" diameter hole just under 5/8" deep in the center of the bottom of your camera body. Drill another hole the same size in the center of one side. These holes are for the tripod mount. Be careful not to drill completely through the wood.

15) Counter sink each of the 11/32" holes with a 1/2" bit to a depth of about 1/8". This allows the top of the tripod insert nut to be flush with the surface of your camera.

16) Hammer in the two insert nuts for use as tripod mounts. I put a little bit of Elmer's Stix-All on the nuts before hammering them in. After it dries, clean up the excess glue.

17) Glue the four edges with woodworking glue and clamp them together making sure that all the pieces are aligned and that the box corners are square. The side pieces fit inside the top and bottom pieces. See the back view drawing of the camera for details.

18) After the glue has dried, check the camera for any gaps and fill them in with wood putty.

19) Find the exact center of the 'lens' board and cut a 1" square hole in the center of the 'lens' board.

20) Sand the outside of the camera and, using the palm sander, round over all of the outside edges. (I used 150 and 220 grit sandpaper.) Also sand the camera back piece and the 'lens' board. Make sure to smooth the edges of your 'lens' hole.

21) Cut a piece of 1/16" thick plywood to about 2" X 3". This will be your shutter. While sanding, slope three of the edges so that it will slide easily in the guides you'll build in the next step.

22) On the 'lens' board, build a 'U' shape of 1/16" X 1/4" balsa wood that the shutter will fit into. Then glue a slightly smaller 'U' on top of the first one, forming channels that the shutter will slide in. After painting, it may help to wax the edges of the shutter.

23) Spray paint the camera body, back, shutter, and 'lens' board flat black. Use several coats of paint. You may also want to paint any hardware such as window clips and screws at the same time.

24) After the paint has dried, glue felt to the front edge of the 'lens' board rabbet in the camera body along with the back edges of the film holder rabbet. As you look through the camera body from the front, you need to felt the edge of the rabbet that faces you, not the edges to the sides. This also holds true for the back of the camera. Be sure to leave a small gap in the felt at the correct location for the ridge in your film holder. This allows the film holder to fit tight up against the felt without any light leaks and also helps keep the film holder from slipping.

25) Glue felt to one side of the camera back, leaving a gap in the felt for the ridge on your film holder.

26) To finish off the 'lens' board, glue the pinhole to the back of the 'lens' board and then tape over the edges with black electrician's tape.

27) Drill a small hole in one of the narrow ends of the shutter and tie a loop of thread through it to make it easier to open the shutter. I then close the shutter by hand.

28) Drill four holes in the front edge of the camera body and mount four plastic window clips to hold the lens board in place. Carefully measure the fit of these clips as you may need to rabbet in the front edges of the camera by less than the 0.2" in my plans to make the 'lens' board fit tight.

29) The back of the camera is held on by surgical tubing, which is connected to the camera by looping it around four screws in the thicker parts of the sides, not in the rabbeted areas, so that the screws don't poke through.

30) On my camera, I screwed in two circular bubble levels on the sides opposite the tripod mounts to make it easy to level the camera. This is overkill. It should be sufficient simply to carry one circular bubble level in your camera bag.


Sources

  Pinhole Resource
  Star Route 15
  P.O. Box 1355
  San Lorenzo, NM 88041

  B&H Photo
  420 Ninth Avenue
  New York, NY 10001
  1-800-947-6628

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Top piece Sides Bottom piece 'Lens' board Back view of camera body Stereo pinhole photography Using your pinhole camera Pinhole gallery Back to pinhole home page Back to home page