Build an Anamorphic Pinhole Camera

As digital photography slowly takes over, there will always be some things that digital cameras just can't do.  One of those things is making anamorphic images!

An anamorphic camera (or lens) is any device which creates a picture where the image is distorted in some manner.  It is commonly used for filming widescreen movies, because without an optical adjustment there would be portions of the top and bottom of the frame that would be wasted by black bars.  The lens stretches the image vertically so that it fills the film.  When being projected, a complementary lens stretches the image horizontally so that the image returns to normal, and with higher quality than if this method had not been used.

That is an example of simple, correctable distortion.  The camera I'm going to show you how to make actually holds the film in a cylindrical position (lets see a digital camera do that!) so that the resulting image is heavily distorted in interesting and awesome ways.

Step 1: What the Heck Is This Camera Doing?

The science of pinholes is covered in my previous Instructable if you are new to pinhole cameras I recommend you read this Instructable before continuing if you want to fully grasp the concepts shown here.

Now that you've seen the results, you're probably pretty confused.  I'll do my best to explain whats going on here but it is very unconventional.  The film is held in a cylinder instead of a flat plane like in a conventional camera. As a result, the pinhole is projecting an image onto a non-flat object.  This inherently causes image distortion, like the way road lines look short when driving and long when on the sidewalk.  Then once the film is unrolled the image appears even more distorted.

The resulting image has lost the center of the scene, and the rest of the scene has been contorted from a round image into a rectangular one as illustrated by the red and blue lines in the image below.

Because these resultant images are so distorted it is very difficult to imagine how the scene will end up when preparing to take a photograph.  It is almost entirely up to luck but a key point is to have the scene full of objects, because bland things like the blue sky will not show the distortion the way buildings or trees do.

When it comes to designing an anamorphic pinhole camera, there are some modifications to the standard rules of pinhole design.  Basically, the focal length of the pinhole should be at the far end of the film, and the near end of the film should be inside the maximum image cone that the pinhole produces.  The pinhole I used is 0.3mm diameter, and in 0.003" material, resulting in a 150 degree image cone.  The resulting design captures things in the image from 41 to 129 degrees from center.

Since the film is closer to the pinhole at one end and farther at the other, the effective aperture of the pinhole changes with this distance, but since the closer film is at a wider angle to the pinhole, the pinhole's effective diameter is reduced, so it does not become over exposed.  Its an imprecise science but it works pretty well.

Step 2: The Design - Materials and Tools

The design is quite simple.  The camera is a light-tight box with some fixtures to hold the film spool and take-up spool, and an acrylic tube which the film wraps around. Two aluminum rollers help the film around the tight corners off the spools so that the cylinder can have near-360 degree coverage. At the end of the box where the tube is glued is where the pinhole sits.  The camera is made of 1/4" poplar but any wood will do as long as it is 1/4" thick.

Now, I used a laser cutter to cut my wood, but there is nothing here that couldn't be done with a table saw, finger joint jig, drill bits and a scroll saw.  If you do have a laser cutter handy or you want to have it cut by an online laser cutting service I have included an Autocad DWG of the design.  For people doing it by hand I have included a PDF template of the parts at 1:1 scale to be printed on 11x17 paper or across two 8.5x11 sheets. 

In the supplied AutoCAD file, white(black) is the cut line and blue is the engrave layer.  The engrave is just to mark some drill holes which are small and need to be a pretty accurate diameter.

Materials required:

• 5" wide x 4' long x 1/4" thick poplar board.  Must be very flat.  This wood tends to warp while sitting at the store so check your piece to make sure its good. 
• 1 foot of 3/8" wood dowel
• 0.3mm pinhole ( DIY or purchased)
• Aluminum sheet metal
• 65mm of 2" outer diameter acrylic tube
• 1 foot 1/4" aluminum rod
• 2x 1/4" retaining ring
• 2x aluminum washer
• 2x 10-24 3/4" screw
• 2x 10-24 wing nut
• 2x 10-24 nutsert
• 6x #4 3/8" flat head screw
• 4x #4 3/8" round head screw
• 3x #4 washer
• 1/4-20 nut
• 6-32 1/4" flat head screw
• 6-32 acorn nut
• Sheet of felt
• Sheet of craft foam
• 2x 1/4" shaft knob
• Wood glue
• Epoxy
• Super glue
• Black spray paint
• Stain
• Spar urethane
• Sandpaper
• 2x 120 film spool
• 120 film paper backing for testing

Tools:

• Laser cutter (or bandsaw, finger joint jig, table saw)
• Drill press with forstner bits and twist drill assortment
• Sheet metal cutting tools
• 4-40 tap
• Lathe (optional)
• Misc. other common tools

Step 3: Cut and Glue Pieces

Cut the pieces out of the 1/4" poplar using a laser cutter.  You may need to experiment to get a good cut without too much burning.  I recommend doing multiple passes (took my 45W laser 6 passes) with a 0.05" Z-offset on each pass.  If doing it without a laser you can use a table saw jig to cut the fingers with a few tweaks.  The rest of the shapes can be cut with a bandsaw or tablesaw, and a scroll saw for the intricate parts.  Replace the hexagonal hole for the 1/4-20 tripod nut with a simple round hole and just fill with epoxy.

Something I should have done before doing all the gluing is drill a 2mm deep pocket for the retaining rings to sit in. Use a 1/2" forstner drill bit.  See Picture 5.

The finger joints fit together really easy so all the joints can be glued and clamped easily.  Cut three 2.56" long pieces of 3/8" dowel and sand down 1/4" of the end of the pieces so they fit in the spool holder with the flat-sided holes. See Picture 4.

Glue the spool holder with the round holes goes on the bottom side of the box lid, then glue the dowels into the holes and glue the other spool holder on top.

Step 4: Drilling

The pinhole plate mounts to the lid using #4 wood screws, which need a 5/64" diameter hole.  The laser file has markings for etching into the wood for where those holes are supposed to go so simply drill into the center of those markings.

Cut two 3/4" long dowel segments and glue them into the holes on the lid as shown in Picture 2.  They will serve as guides to align the screw holes when the camera is assembled.

On one of the sides of the box there is a 3/8" diameter hole for viewing the film frame number.  There needs to be a 5/64" hole drilled next to it for the little rotating metal piece which covers the hole to prevent excess light from getting in. 

Step 5: Making the Metal Pieces

With the body of the camera coming together, some of the finishing touches can be done.

The film rollers are made of 1/4" aluminum rod.  One end is turned down to 0.08" diameter for a length of 1/4" so it can be inserted into a hole in the wood.  The other end is drilled with a #43 and tapped for 4-40.  This will help keep the friction on the film down so it goes around the bends without ripping. (Picture 1 and 2)

The pinhole mounting plate is a piece of aluminum sheet with a 5/16" hole drilled in the center and four 7/64" holes around the perimeter.  This step has a PDF attached for use as a template printout.  The holes are countersunk so the flathead #4 screws will sit flush. (Picture 3)

The shutter is made of a small roundish piece with a length of material off the side bent upwards to act as a handle. (Picture 4and 5)

The film number cover is a rectangular piece of aluminum with a hole drilled for a flathead screw and acorn nut as a handle. (Picture 7)

Once those are ready, spray 3M Super 77 adhesive onto the shutter and number cover and press them onto the sheet of felt.  Use an X-acto knife to cut the parts from the sheet. 

Give everything a coat of black paint when its finished. (Picture 8 and 9)

Step 6: Metal Pieces Pt. 2

The film is advanced by a tightening knob and loosening knob, used in tandem to move the film along the cylinder.  I took some of the aluminum rod and filed two sides flat about 3/8" long.  Then I cut a small groove using a thin tool on the lathe for the retaining ring.  then I filed a small flat onto the other end for the set screw to tighten on. Pictures 1-3

I made two brackets with nutserts in them to screw the lid onto the box.  They are glued to the box with epoxy.  I lined them up by screwing them to the lid, then marking where they line up with the box, taking them off the lid and then gluing them in place. Picture 4

Step 7: Wood Finishing

The first thing that needs to be done is painting the inside black.  This prevents stray light from screwing up the pictures.  Just tape off the outside and spray the inside with black spray paint.  Then stain and coat with a lacquer or urethane coating of your choice.  I like Minwax Helmsman Spar Urethane.

Once dry all the corners inside the box need electrical tape on them to make sure they are light tight.  Take a small piece of aluminum and epoxy it inside the box over the hexagonal nut hole.  Add some more epoxy to the hexagon hole, and insert the nut. 

Step 8: Assembly

Once the coating is cured assembly can begin.  Epoxy the acrylic tube on the lid with the big hole right in the center. 

Use the four #4 flat head screws (brass ones in my case) to attach the pinhole mounting plate.  Use the two #4 washers to lift the shutter up above the plate and give the felt some breathing room.  Fasten it with a #4 round head screw, tightening it so that it holds itself down firmly enough that it doesn't move without being pushed.

Use another #4 screw and washer to put the film number cover in place.  I inserted a small piece of acrylic into the hole but without a laser cutter making that piece might be difficult.  It isn't something that is required, just a nice touch I added.  You can see it in Picture 5.

Once things were in place and I started testing out the film movement, I noticed that the spools would fall off the holder after a few turns so I had to add some little tabs that swing in and out to keep them in place.  You can see them in Picture 6.

Insert the knob shafts with retaining ring and washer and tighten the knobs on the surface of the camera.  Load up the two test spools and test paper and see how the film advance feels.  If it is tight try putting some smooth tape on the wood edges so that it has less friction.

I made a small plate for on the front of the camera so that I know what aperture the pinhole is and the numbers that I need to wind the film to for each shot.  I glued it on with epoxy.

The lid and box are fastened together with a pair of 10-24 machine screws converted into thumbscrews by tightening them into a wing nut.

Step 9: Finished Results, Taking Pictures, and the Future

Using the camera is difficult because it doesn't take conventional photographs.  When it comes time to compose an image all you can do is aim the pinhole at the scene and hope for the best.  The images always come out interesting.

Using the camera:

Loading the camera isn't too difficult, the paper starter can be slid in from the top and hooked to the take-up spool.  The film is advanced using the two knobs.  The knob for the supply spool is turned to loosen the film and the knob for the take-up spool is turned to advance the film.  Used together the film will make its way along the pathway.  The film has to be wound to #2, then #5, #8, #11 and #14, of 16 total.  These are the frame numbers for a 4.5x6cm framing, but each shot from this camera uses 3 of those so the numbers must be advanced by three.

Calculating exposure can be done with any light meter or most digital cameras.  Determine the shutter speed for the scene with an aperture of f16 and use the included PDF chart attached to this step to extrapolate the time required for the pinhole's aperture of f116.  Add a little extra time if the required shutter speed exceeds 120 seconds.  Refer to your film's datasheet for "reciprocity failure compensation" for long exposure times.

Improvements:

After shooting my first roll I have found some interesting issues with this camera that could benefit from some improvements. I will update this Instructable as I explore some ways to correct the issues, but for right now it does work.  Composing the images with any degree of accuracy is nearly impossible and I don't see a way that a viewfinder of sorts could even be created.  The large surface area of the acrylic puts a lot of friction on the film, which was something I wasn't expecting to be an issue initially.  Testing with 120 paper backing worked fine but the film (which is emulsion side down) has so much friction that it was very difficult to wind.  I don't think there was any danger of ripping the film so larger knobs would help give a mechanical advantage.  Also, using an exposure chart that I created for one of my previous cameras caused all the images to be greatly overexposed.  I have included a new exposure chart PDF which is more accurate.

Tips for shooting:

It seems that scenes with a very high natural contrast works best.  Scenes with lots of straight lines look particularly interesting too.  Large multi-pane windows, tall buildings, etc.

Step 10: In Conclusion

Pinhole photography is not an exact science, and I am no master, so if you have any suggestions, feedback, comments, or take issue with anything I have written please let me know and I will respond or make appropriate changes/additions. 

Thanks very much for reading!