Pinhole camera designs can be incredibly varied. The traditional scout-troop model was built from a Quaker Oats carton, exposing a single sheet of photo paper. But “single shot” pinholes are a bit inconvenient, especially as fewer people have access to a darkroom these days.

So lately I’ve been emphasizing pinhole designs using roll film—like my plasti-pinhole project and it’s siamese twin variant. (I also designed a 120-film camera for shooting 6×12 panoramas, a project you can find in the Best of Make book.)

Pinhole image on Fuji Acros 120 film, taken with a converted 1950s Argus 75 camera

But I’d like to give a little background that applies to all pinhole cameras, of any form. Then we’ll look at a method for fabricating the all-important pinhole itself.

Some Theory

So why does a pinhole camera work? Imagine a light-tight box, with a piece of film on one side and a tiny hole in the other. Each point on the film can only “see” one patch of the outside world, the one lined up with the pinhole—whether it’s light, dark, blue, red, etc. So an image of the scene forms upside down on the film.

With that idea in mind, visualize what happens if you move the pinhole closer: The angle from the film corners to the pinhole gets more oblique, and the camera takes in a wider view of the outside world.

In fact, the distance between the pinhole and the film is exactly equivalent to the focal length of a lens with the same coverage. Hence, it’s most informative to measure pinhole “focal lengths” in millimeters, just as with lenses. (Because a pinhole does not actually focus light, using focal length in this sense is technically a misnomer—but that’s the way most pinhole enthusiasts refer to it.)

So How Large is a “Pin” Hole, Anyway?

Up to a certain point, the smaller the hole you use, the sharper the image you get. But if you go too small, you run into a problem with diffraction—the tendency of light waves to fan outwards when they graze the edge of an obstruction (it’s a problem for lenses, too).

Thus, there is one hole diameter for any given focal length which gives the optimum possible sharpness. Historically, a number of great scientific minds labored to derive the proper formula to compute this. But today, you can just put your faith in a handy online calculator, like this one from Mr. Pinhole.

For typical cameras the best diameter works out somewhere between 0.2 to 0.5 millimeters—equivalent to an f/stop of f/100 to f/300. This definitely implies some long exposure times might be needed. But everything from infinity to inches away will be recorded with equal sharpness.

If you want a camera covering a particular angle of view, you have a choice between using a small piece of film with a short focal length, or building your camera using a bigger image format and a longer focal length. For example, a 30mm focal length on a standard 35mm film frame gives the same coverage as a 225mm focal length exposing an 8×10″ sheet (both show about 72° diagonally). But which is better?

As it turns out, the optimum pinhole diameter scales up more slowly than the focal length: The bigger you build the camera, the smaller the resulting f/stop, and the sharper the image. But eventually, ever-larger image formats can become cumbersome, costly, and impractical. (And besides, if it’s more sharpness you want—you could always use a lens!)

My own conclusion is that 120-film pinhole cameras offer a good trade-off between image quality and film-handling convenience.

How Do I Make a Pinhole?

The goal in fabricating a pinhole is to get one that is nicely circular, without ragged edges, and whose diameter you have at least roughly measured.

You’ll probably do best by piercing your hole in the thinnest possible material. If your pinhole more resembles a microscopic “tunnel,” oblique light rays will be blocked and you’ll get noticeable vignetting. While that effect can be interesting to explore, you’ll likely also see problems from light reflecting off the inner walls of the hole, degrading contrast.

While it’s fine to experiment with tinfoil or the side of a beer can, I settled on a method for fabricating pinholes in aluminum roof flashing (about 0.01″ to 0.02″ thick). I just find it more secure to fasten those flat, stiff sheets into whatever camera I’m building.

First, start by cutting squares of metal 50mm on a side. Why 50mm? Because it’s the same size as a 35mm slide mount—this may come in handy when it’s time to measure the pinhole diameter. Cut several extras, since there’s often a bit of trial and error in achieving your target pinhole diameter.

Place the metal square onto a piece of softwood, and tap a small dimple into the center. A ball-peen hammer works fine; however it might be easier to center the dimple if you hold something like the rounded head of a carriage bolt against the metal, then strike that with the hammer.

The dimple only needs to be high enough that you can selectively rub that spot against a sheet of sandpaper to thin it.

Press and sand the bump against fine sandpaper—320 or 400 grit works well. Here I show the sandpaper wrapped around a block of wood, to make it easier to hang onto; flexing the edges of the metal backwards will help avoid sandpapering your fingertips!

You want to rub with enough pressure that you’re definitely removing metal, but not so aggressively that you sand right through. After a noticeable flat spot has formed, it’s time to start checking your progress.

Gently press the tip of a sewing needle against the hollow of the bump. You are not trying to push it through yet—hold the needle by the sides to avoid applying too much pressure.

What you are testing is whether the metal is thin enough so that the tip of the needle telegraphs a tiny raised point through to the other side. If not, go back to the sandpaper and rub a bit more, then test again.

With your first test, you probably left a small pin-prick in the metal. Keep placing the needle in the same spot after that, to avoid inadvertently forming multiple pinholes.

Once the metal is thin enough for the needle tip to deform it, you should see something like this:

Take a couple of light strokes against the sandpaper to flatten the raised point. Now hold the metal up to a strong light—it’s possible that a tiny hole will show through already. But in any case, you’re getting very close.

Press the bump against a firm backing, like a telephone book. Replace the needle tip into the pin-prick you started, then give firmer pressure, pushing on the end of the needle as shown. You are not trying to push the needle through the metal—the diameter of its shaft is much too large. With gentle pressure you’re just trying to to push the point of the needle through.

Once you “see daylight,” go back to the sandpaper and lightly sand away any rough edges around the hole. Take the tip of the needle and very gently spin it in the hole to help round off any irregularities. Blow through the hole to remove any dust from the sandpaper.

Now It’s time to check if your hole looks clean, round, and what its diameter is.

It’s not necessary to achieve insane precision with your pinhole size. If you have nothing handy but a 10x magnifying loupe and a millimeter ruler, you can sort of “eyeball” whether your hole looks like one third of a millimeter, or whatever. Remember that a hole as far off as 70% or 140% of the desired diameter only means one f/stop of under- or overexposure, respectively. (This is within the exposure latitude for many kinds of film.)

But there are two easy methods to get a more precise measurement: Either use a slide projector, or a scanner connected to your computer. Today far more people have access to scanners than still own slide projectors—so I’ll describe that method first:

Simply put the pinhole metal into the scanner, and scan at the highest available resolution. (Only scan a small selection around the hole itself, to avoid ridiculously bloated document sizes.) Either scanning the hole on a flatbed document scanner or with the slide holder of a film scanner is fine—although a film scanner may offer higher resolution.

Some photo-editing software has a ruler tool allowing you to measure sizes directly. But even in a more basic program (like the old version of Elements shown here), you can still measure the hole. Drag out a selection which just barely encloses its image; then open the “info” palette to read off the size.

A highly-magnified scan of the pinhole; the selection is 107 pixels square. There also appears to be some gunk clinging to the hole that should be cleaned out

To get the most accurate measurement, I suggest going into the preferences and changing the default units to pixels. If you scanned the hole at 9600 dpi, and your selection is 107 pixels across, its diameter equals 107 divided by 9600, or 0.0111 inches. There are 25.4 millimeters in an inch, so that pinhole size translates to 0.28mm.

Personally, I find there is a lot of trial and error in achieving at a nice clean pinhole of the correct diameter. So I will often make a batch of pinholes at the same time, to get one good one. In that case, the scanner method becomes a little time-consuming.

So to me it’s worth setting up an old slide projector with a manual feeder, where I can quickly slap pinholes in and out, and immediately see how they look. This allows me to start with a hole slightly undersize, then nudge its diameter larger (by gently spinning the needle tip in the hole), quickly rechecking until I hit the target size. (Sandwiching the pinhole into a spare cardboard slide mount makes it fit in the projector gate more snugly.)

The key thing is to know that the opening of a standard slide mount is about 23×34mm. From the height of a slide image projected onto the wall, you can calculate the magnification; and from that, you can figure out how large the spot of light would appear from a properly-sized pinhole.

But I have an even simpler trick: Move the projector back and forth until a complete slide is projected at a size of 46 by 68 inches. At that magnification, every inch of the projected image represents 0.5mm at the slide mount. Thus you can read off pinhole sizes very rapidly (a ruler divided into tenths of an inch is helpful).

Measuring the projected image of a pinhole

If you discover you went wildly over your target pinhole diameter, start over with a fresh piece of metal, but try to press more gently with the needle this time. And don’t throw away the “bad” pinhole. Just write its diameter onto the metal using a permanent marker, and hang onto it somewhere. Building pinhole cameras is rather addictive; a day may come when you create another one needing exactly that diameter hole.

Figuring pinhole exposure times means knowing the equivalent f/number. This is simply the focal length of your pinhole camera, divided by the pinhole diameter. (But both need to be expressed in the same units, whether millimeters or inches.) It’s preferable to avoid f/numbers under f/100, just because the correct exposure in full sun will be a fraction of a second—not something most homemade pinhole shutters can time accurately.

When you need to calculate exposure times, few light meters will indicate f/stops all the way into the hundreds! So it’s helpful to know that f/128, f/181, and f/256 are exactly 6, 7, and 8 stops smaller than f/16. Find the indicated exposure time at f/16 and count off the steps to the correct (longer) time needed for your pinhole exposure.

Have fun!

I must confess that in the past, I rarely used Polaroid cameras, finding the “$1 per image” aspect a little daunting. But also, most of their plasticky, auto-exposure consumer models seemed rather lacking aesthetically. (I do make an exception for the SX-70 camera—which still seems as futuristic today as it did when it came out in 1972.)

But in the spirit of savoring our Polaroids while we still can, recently I bought some type 669 film packs.

These peel-apart films are an older technology than Polaroid’s “integral” types like 600 or SX-70 Time-Zero. But the peel-apart pack type was adopted for so many professional and technical uses that demand remained high until digital arrived. So there are several packfilm emulsion types still available. Even Fuji has now started making a line of compatible film packs.

I’m skeptical that another manufacturer will start up making Polaroid’s integral films: It’s a much more complex technology (each pack includes a unique flat PolaPulse battery). But it’s nice to feel I’ll have the Fuji backup option, if I end up falling deeply in love with my pack-film projects.

Anyway, as I mentioned, I was never that fond of Polaroid’s own cameras. This started me thinking about “alternative” ways I could expose images onto 669 film. So today I’ll show the first of two Polaroid camera hacks: The PackPola Pinhole.

This one is so ridiculously easy that it barely deserves the name “DIY project.” Here is the executive summary:

STEP 1: Find a Polaroid microscope camera
STEP 2: Tape an 0.4mm pinhole behind its dark slide
STEP 3: Take pinhole photos

But, oh all right—if you insist on making things more complicated, here are some additional details.

While most of the later pack film cameras were plastic-bodied, Polaroid did manufacture a stout cast-metal body which was used for certain products—in complete cameras, or as a dedicated Polaroid back for technical uses. The model shown (which I was told was a microscope camera) has a rigid cast-metal “pyramid” where a civilian Polaroid model would have bellows, with a custom attachment flange on the front.

Aside from the nice brushed-metal finish, this camera has two useful features. First, it has a real live tripod socket on the bottom (vital for long pinhole exposures). More importantly, its microscope fitting comes equipped with a dark-slide—we can reuse this without modification as the shutter for our pinhole camera. (I gather microscope photos must require long exposures too.)

Now you could build a Pola-pinhole by hacking a regular bellows style camera too—and these models are practically being given away today. You’d need to remove the front of the lens/shutter assembly, and attach a pinhole behind the bare lensboard. (See the excellent step-by-step disassembly photos here—also getting a chance to practice your Italian!) But in that case, you would need to improvise a shutter, and the focal length will be about 30mm longer (and hence less wide-angle-y) than with the microscope camera.

The pinhole is pierced in a thin sheet of metal—the sidewall of a beer or pop can is ideal—and taped inside the “pyramid” behind the shutter. This gives a focal length of about 74mm. (The diagonal of a packfilm image is about 120mm, so this yields a wide-angle coverage similar to a 28mm lens on 135 format.)

For that focal length, the optimum pinhole diameter is roughly 0.4mm or 0.015 inch. This equates to a pretty tiny f/stop: the nearest whole stop value is f/181. That’s 7 stops smaller than f/16—useful to know when trying to translate light-meter readings into pinhole exposure times.

Back up your pop-can metal against something firm like a phone book, then just barely pierce the metal with the tip of a sewing needle—don’t poke all the way through! Sand away any rough burr around the edge of the hole using fine 320 or 400 grit emery paper. Twirl the needle tip in the hole to smooth any raggedness—you want the hole to be nice and round.

You can measure the diameter of your pinhole exactly, by placing it on a flatbed scanner and scanning at the highest possible resolution. Knowing the exact DPI of the scan, and reading off the dimensions of a selection just including the hole, you can see if its diameter is in the right ballpark.

I often start with a bunch of metal blanks of 50mm square, a size that will fit inside a cardboard 35mm slide mount. By setting up a slide projector at a known magnification, I can quickly go back and forth between checking sizes and roundness and gently enlarging holes with the needle to reach the desired diameter.

Of course, one great advantage of a Polaroid pinhole is that you can just wing it. Try an exposure at what you think your equivalent f/stop is. If it’s too light or too dark—next time use a revised guesstimate of your f/number when you figure the exposure.

Polaroid 669 is well-known for “interesting” color shifts when developed in cold temperatures; but also when using the kinds of longer exposure times needed for pinhole work. With a multi-second-long exposure under open sky light, you can have quite a strong blue/cyan cast:

You might enjoy this effect—or, you can tape a warming filter in front of the pinhole.

In direct sun, start by trying one of the #81 series filters. But for longer exposures or in cooler light you may need a stronger orange/salmon colored filter, like one of the #85 series. If you can get your hands on a swatch-book for theatrical gels (like Roscolux), that would offer a huge range of colors to try (with pinhole work, you’re not exactly worried about the optical flatness of the sheets).

Personally, I raided my cache of oddball Series VI filters, and found a perfect Harrison brand color-correction filter, designated “C3.” This filter loses a little less than one stop of light; I used exposures of about 3 seconds in full sun, up to 30 seconds in darker shade. The color palette of 669 seems to give a nice pastel softness, thought without much saturation in the reds & yellows.

If you have never used pack film before, you may be flummoxed by the profusion of weird tabs that sprout from the end of the camera (from a slot helpfully labeled “4″). This becomes easier to explain when you understand that pack film is actually negative and positive sheets stored separately, which need to be sandwiched together to start development.

The first black tab pulls a light shield out of the way, and uncovers the top negative sheet. After you make an exposure, pulling a white tab slides the exposed negative around into contact with the positive print paper. However both are still dry at this point, and nothing happens yet.

Pulling out the wide arrowed tab bursts a pod of chemical paste, and the two chrome rollers smoosh a uniform layer of this goo between the positive and negative, starting development. After 60 seconds, the image is fully transferred and you can peel the print away. It stays a little tacky for a few moments, so don’t accidentally get it stuck to another print.

I discovered pretty quickly that my microscope camera pack-holder had a couple of quirks—possibly the reason why it had been retired and discarded in the first place. The first is that its rollers seemed to have gotten tired, and weren’t spreading the developer goo all the way to the far edge of the print. But actually, the white blobs caused by this were one of those serendipitous creative accidents that I ended up liking.

The other issue was that there was a serious light leak somewhere in the camera body. Now, remember that a pinhole (like a lens) forms its image upside-down. So this radiant splash of light at the bottom of the print was coming from somewhere on the top of the camera.

Eventually I realized there was a tiny gap at the seam where the pyramid cone attached to the film back—perhaps the camera had gotten dropped once. A bit of electrical tape fixed that up. But as light leaks go, this may be one of the more beautiful ones I’ve seen!

One rationale for that project was that nowadays, it’s getting harder to buy and develop any film size besides 35mm. Pinhole cameras made for other odd formats are certainly fun, but sometimes require access to a darkroom to make them practical.

But one of the joys of pinhole photography is being able to try out bizarre, idiosyncratic camera designs: Weird-shaped frames, ultra-wide-angle coverage, or warped perspectives from curving the film plane.

The moderately wide coverage of the normal plasticam pinhole is interesting; and its standard 24×36mm frame makes developing the film at any lab easy. Yet compared to more exotic possibilities, it does begin to seem a little tame…

A Japanese woman on Flickr wanted to make a panorama-format pinhole camera. Her inspired idea was to take a plastic Holga, and saw it into pieces. She reused its film-supply and take-up-spool compartments, but replaced the middle section with a homemade “stretch limo” version: A light-tight box with film gate, pinhole and shutter. Genius!

A Holga uses 120 film of course; but she inspired me to consider doing something similar with 35mm film. (Aside from getting interesting widescreen framing, with pinhole cameras a larger format helps give a more detailed image.)

The way I build a 35mm plasti-pinhole, the original shutter is discarded; so it’s not the button on top that takes the picture any more. But the film-winding mechanism remains intact. As you wind, a toothed wheel allows 8 sprocket holes to go past, then locks; this yields the standard-width frame spacing. You still need to click the button on top to release the winding thumbwheel, before you can advance to the next frame.

But you do this independently from making the exposure. And I had an “aha” moment when I realized that if you clicked and wound twice between pictures, that standard mechanism would permit shooting double-width images: 24 x 72 mm!

But how to build the rest of the camera?

Here is my whimsically warped solution: I took two identical plastic trashcams, and sawed through them, exactly at the edges of their film gates. Then I glued and taped them back together “siamese-twin” style, to make a panoramic pinhole camera.

Two focus-free plastic 35mm cameras; $1.40 for the pair at my local thrift store.

A majority of trashy plastic models use curved film gates, to mask the deficiencies of their crummy lenses. But for this purpose, finding two matching cameras with flat film gates makes construction much simpler.

Some plasticams have their own “panorama” mask which you can swing into place. But all those extra parts would add more complications, so I shunned that style too. These two ultra-simple Bell & Howell trashcams turned out to be perfect.

I arbitrarily chose one camera for the supply-compartment half, and the other for the film takeup side. Then I disassembled both cameras and discarded all the unnecessary bits and pieces inside—lenses, shutters, springs, etc. It’s important to remove all stray metal parts before sawing into the camera body!

Discarding useless innards; black lines mark the approximate cut locations

Unlike in my standard plasticam-pinhole, I could not reuse the sliding lens guards as a shutter: The pinhole opening would not be aligned with either camera’s original lens position. So all those moving parts got tossed too.

Next I screwed the shells back onto the camera bodies, wrapped tape around both to hold their backs shut, and sawed through each one.

The crapcam types shown here include dummy weights glued into their bases (to lend an illusion of quality!) It was particularly tricky to avoid grinding the saw blade into those metal chunks—so be careful. An old hand-saw miter box is a great tool for getting a straight, square cut.

I sawed just inside the right edge of one camera’s film gate, and the left edge of the other. This still left some interior partitions standing in the way of the desired pinhole location, all of which needed to be cut away with a sharp knife.

Now, I wish I could say I used some sophisticated assembly technique to combine the two bodies. But really I just spooged the halves together with copious amounts of black silicone sealant—supplemented with much electrical tape. I was trying to fill all gaps where light might leak in, and keep the now-combined film gates as well-aligned as possible.

I also glued an aluminum bar across the two film-door halves, so the back would swing open and latch shut correctly as a single unit again.

A piece of aluminum sheet with an 0.2 mm pinhole went across the front of the camera body. Positioned only 26mm from the film plane, I knew this camera was going to give some wide-angle coverage! (Horizontally, it’s about 110°.) The pinhole size works out to f/128, for those of you keeping track.

For this camera I tried a new shutter idea, a design which has quickly became my absolute favorite. I will definitely be using it again for any future pinhole cameras.

I took a spare cable release I had lying around, and cut away the rotating barrel intended to thread into a shutter button. This uncovers enough extra length of the moving shaft to allow me to hot-glue it to a piece of thick black cardboard. Then the cable sheath is glued to the front of the camera body.

The moving shutter piece is outlined in red here. It has a cut-out which uncovers the pinhole as the cable release is pressed. A couple of scrap pieces glued around the edges guide the moving panel.

What’s wonderful about this design is that the cable-release’s own internal spring snaps the shutter closed again—or, it can be locked open indefinitely with the set-screw of the release. And there’s no jiggling the camera when you open the shutter.

The front shell of the camera needed a matching rectangular opening cut into it. Then finally, I screwed and taped the camera shell back together again. (There’s no particular significance to the metallic tape—it just hides several no-longer-needed openings in the camera’s front panel.)

The block of particle-board contains my usual homebrew tripod socket: A 1/4-20 nut epoxied into a hole in the bottom.

For a while I was jokingly calling this camera the “HaxPan,” in reference to Hasselblad’s multi-thousand-dollar panoramic XPan camera system. Of course, my camera covers a wider angle than even its 30mm lens (as well as saving a few pennies… )

Obviously no ordinary lab will know how to make prints from these crazy non-standard frames. But the negatives can be developed just like any other 35mm, and then scanned on any of the current inexpensive flatbed film scanners for further processing.

Making this camera was truly an experiment. There are still a couple of small light leaks at the joint between the cameras. And next time I would probably do a few things a little differently…

Placing the pinhole so close to the film does give extremely wide views—but you can’t see much detail at the edges, because the light fall-off is so extreme. And a 110° angle of coverage is so hard to visualize without a proper viewfinder that I found framing to be quite hit-or-miss.

So next time, rather than placing the pinhole so far back, I would build up the light-tight inner compartment a little deeper and use a slightly longer focal length.

But that’s the great thing about pinhole cameras: The cost of experimenting is low… and the fun of blazing new ground is priceless.

Happy hacking!

Sample photo from the double-width 35mm pinhole. Note small light leaks at the seam between camera bodies. More samples here.

Part One covered choosing the right trashy plastic camera to use, then taking it apart. The crucial point to remember is that your camera must have a little lens-cover flap, which will become the new shutter after the pinhole mod.

Trashing and Hacking

With the camera’s lensboard removed, we expose the original spring-operated shutter blade (see the final photo in Part One).

Pull out the original shutter blade and spring, and throw them away. If you had already removed the lens, throw it away too. But keep its retaining ring—we will need this later.

If the lens was glued into place from the back of the lensboard, you may need to shatter it by tapping a nail through it; then pick out the fragments.

Now you need to decide the best location within the camera’s innards to place a thin metal wafer for your pinhole. The deeper back into the camera body you choose, the wider the angle of view you’ll get in your photos. But if you go too wide, the edges of the opening in the front shell of the camera can creep into the field of view.

With this model I decided to take a chance, and glue the pinhole behind the lensboard. For cameras having only a small opening through the front shell, a pinhole mounted in the front of the lensboard is better.

The original shutter blade pivoted between some molded ridges, both on the main body piece shown here and on the back of the lensboard. With a sharp blade, shave these away, so that there will be clearance for your pinhole’s sheet metal.

The aperture stop in the lensboard also needs to be trimmed away, to insure it doesn’t obstruct the pinhole’s view. But keep the raised collar around the opening intact.

Finally, enlarge the front opening of the retaining ring. This image shows the ring after widening its hole as far as possible.

Remember that our shutter flap will slide against this ring; so its front face needs to remain flat and without rough edges.

(If your lens was glued in from behind so you don’t have a retainer ring, the same consideration applies to the raised collar on the lensboard.)

Pinhole Time

Next we need to choose the right pinhole size, and make the actual pinhole.

The distance from the pinhole to the film plane determines the right diameter for the hole, so find a way to roughly measure this distance on your camera. On my particular model it’s 25mm. This functions like the “focal length” of your pinhole. And whooeee—25mm is a real wide-angle!

You might imagine that the smaller you made your pinhole, the sharper the image would be. But it’s not quite that simple. Light waves grazing the edge of the hole diffract in unwanted directions. So there are formulas for calculating the hole diameter which yields the best sharpness, given a particular focal length.

Actually, using 0.2mm is close enough for most plastic trashcams; but you can get more precise using an online calculator like the one at Mr. Pinhole’s site.

That calculator also tells you the equivalent f/stop of the pinhole, which in my case is f/119. That’s near enough that I’ll round it off to f/128, exactly 6 stops smaller than f/16 (helpful to know when it comes time to determine exposures).

Fabricating a Pinhole

There are several schools of thought on the best method for making a pinhole, so I’ll keep things brief in describing my method.

I tap a small bump into thin sheet metal (pop-can sidewall will work); then sand the bump against 320-grit sandpaper until the metal is paper-thin. I press the bump against something firm like a phone book, and with the very tip of a sewing needle, pierce the tiniest hole I can. The shaft of the needle mustn’t go through.

I use squares of metal 50mm x 50mm—the same size as a 35mm slide mount. This lets you use the slide holder of a film scanner (or, a slide projector) to get an enlarged view of the pinhole. The hole needs to be nicely round, and not ragged; and by knowing the scan resolution (or magnification of a projected slide) you can calculate the diameter.

By gently twirling the needle tip in the hole, and lightly sanding after, you can nudge the diameter larger until you reach your target size. (Blow out any dust before checking it.) You’ll probably need to make a few pinholes to get a good one; but even if the diameter is off by 20%, that’s only a fraction of an f/stop in exposure error.

Place the Pinhole

Trim the edges of the pinhole metal until it fits into the location you chose. If the pinhole is going behind the lensboard (as here), test-fit that there are no remaining ridges or nubs which would keep the lensboard from snapping back into place.

Glue the pinhole in position. I like to use black silicone sealant for this (it’s sold as automotive gasket material), since it blocks light from leaking through any small gaps. Check through the back of the camera that the pinhole is centered, sliding from side to side if needed. Don’t get glue in the hole!

Too Smart For Its Own Good

Next we can start putting the camera back together—with one important final modification.

You may have noticed that your camera originally had a nifty interlock between its lens cover and its shutter button. If the cover flap was closed, the button could not be pressed down.

Once we gutted the original shutter mechanism, the button atop the camera no longer does anything to start exposures (the lens-cover slider will do that instead). But we still need to click the top button each time we want to advance the film to the next frame.

In our finished camera, the cover flap will be closed any time we aren’t exposing film. Hence we need to disable the interlock, so you can click and wind between exposures with the flap still closed. My illustration shows where an arm on the lens-cover slider originally blocked the shutter plunger. Remove the slider, and cut this arm away, and the release button can be clicked even with the flap closed.

Finally, we can put all the parts back together: Snap the lensboard in place, and add the retaining ring. (With the lens missing, the ring may fit loosely, requiring some dots of glue to hold its ears in place.)

Replace the cover flap and its slider, and check that it works smoothly to cap and uncap the pinhole opening.

Time for a Sanity Check

Next, put the front shell of the camera back in place again. (It can take a few attempts to put the front on without dislodging the cover-flap/slider mechanism.) Do not replace the four screws yet—we need to make one important check.

Open the shutter flap; and with the back of the camera open, hold up the pinhole towards a bright light. Sight through the film gate towards the pinhole, rocking the camera back and forth. The pinhole should remain brightly lit from anywhere in the frame—all the way around the perimeter, into all four corners.

Uh Oh!

Trying this test on the camera shown here, I discovered trouble. I realized I’d been too ambitious at trying to get the shortest possible focal length and the widest angle of view. The front shell’s opening blocked the corners of the image!

Remember that a pinhole has effectively infinite depth of field. So the round edges of of the opening would appear sharp in the photos—the pictures would look like they’d been taken through a port-hole. While it might be interesting to play around with that effect, I preferred an unobstructed view.

I solved the problem by taking a file to the edges of the front opening—shaping a bevel with the same rectangular proportions as the 35mm frame. I checked my progress by sighting along the edges of the film gate, and eventually removed enough material: The pinhole had an unobstructed view all the way into the corners. Whew!

With that crisis averted, finally we’re ready to put all the camera parts back together. Replace the latch spring (if yours fell out); the rewind crank (if you removed it); the wrist-strap (if you want it); and the four screws that hold the front shell in place. Make one last check that your shutter flap is opening correctly, and your camera is ready to shoot!

Finishing touches

Because pinhole exposures can be quite long—with indoor light, even many minutes—holding the camera steady during that time becomes a problem.

I suggest adding a flat piece of wood as a base—much easier than the camera’s rounded body to steady against a table, a bench, a door frame etc.

If you have a tripod available, a 1/4″-20 nut epoxied into the base serves perfectly as a tripod socket.

Note that the base needs to be cut short, so it does not cover up the rewind release. (Or if you prefer, drill a large finger-hole lined up with the release button.)

Once you’re certain you won’t need to open up the camera again, glue the base in place (hot-melt glue works great). Just watch out to make sure that the back can still open freely.

Shooting with the Pinhole

This wide-angle style of pinhole camera gives interesting stretched-out, dreamlike images. Both near and far are equally in focus (or equally defocused?); yet anything that moves during the exposure disappears in a ghostly blur. A pinhole camera’s potential for intriguing, expressive images is something I’ll leave it to you to explore.

But if you’re a beginner who would like some basic tips on operating the camera, exposure suggestions, etc., I’ve put them into a PDF file which you can print out and take along when you go out shooting with your new little plastic pal.

Happy pinholing!

[Return to Part One.]

Eighty-cent thrift store fodder becomes intriguing creative tool

This installment, Part One, covers choosing and disassembling your plastic camera. The same steps can be used for other hacks besides pinhole conversion (such as flipping the lens, or reaming out the aperture stop). Later, Part Two will cover the pinhole modification.

Why Do This?

In decades past, it seems that every every Scout Troop in the country showed kids how to build pinhole cameras out of a Quaker Oats carton. That is a fun project—and actually, any light-tight container will work. But you only get a single shot; and as fewer and fewer people today have darkroom access, that camera style has become a bit impractical.

Taking a cheap plastic camera and re-using its film transport lets you try pinhole photography, but keep the convenience of roll films—far easier to load and develop.

Hacking a Holga into a “Pinholga” is a popular project. Yet even 120 film can be challenging to locate and get processed in some towns. But 35mm film and developing are still ubiquitous. By gutting a simple 35mm “trashcam,” you can shoot pinhole images of standard frame size and spacing—making developing easy and accessible for anyone.

Choose Wisely

Thrift stores and rummage sales are often awash in unwanted film cameras today. But for pinhole purposes, you need to choose carefully. You don’t want an autofocus point-and-shoot; you don’t want a camera with a zoom lens. You don’t want an Instamatic (the 126 film format is nearly extinct).

You want the most ultra-basic, 100% plastic, 35mm camera on the shelf. The words Made in China are your friend here. Focus Free is good. The camera should have no adjustments whatsoever—even the sunny/cloudy setting of the ubiquitous TIME camera makes things too complicated for us.

The essential feature we desire is a little plastic flap which swings into place to cover the lens. We’re going to remove the original lens and shutter; so we will use this flap instead to begin and end exposures.

Our hacking candidate

Avoid cameras with built-in flash, for two reasons: first, the flash is useless (with a pinhole’s tiny f/stop, it would only expose correctly a few inches from the subject). Secondly, if the capacitor happens to be charged when you take apart the camera, you can get a nasty shock.

If you open the backs of a few cheapie cameras, and you’ll notice many have a slightly bulged film gate. This helps mitigate the optical flaws of their 1-element plastic lens. But a flat film gate usually means the camera has a 2-element lens—whoo, high tech! A bulged gate results in slightly curved lines in pinhole images, so I prefer the flat style—though perhaps it’s a shame to sacrifice the “nicer” crapcams this way…

Many Chinese cheapies use an odd winding mechanism, where the toothed wheel doesn’t pull on the film to advance it; the teeth are actually pushed by the film’s sprocket holes to cock the shutter. Thus, no film—no cocking. If you didn’t know the score, you might even think the camera was broken. But don’t worry, that style will work fine.

Don’t get too hung up finding the perfect camera to hack, or one matching my photo. They all have different minor advantages and annoyances, so just roll with whatever you can find.

Oh—and don’t spend more than a dollar or two. Even as intact, functioning cameras, they’re barely worth that. You may want to bring home a couple of different types, in case you run into a snag with your first one.

Disassembling the Trashcam

You’ll need a fine-tipped Phillips screwdriver to remove the front shell of the camera (here, the silver part).

After disassembling a few of these cameras, you’ll realize there’s a very strong family resemblance between them— they all seem to come from a small number or Chinese factories. It’s easy to adapt these instructions to different designs, just using a bit of common sense.

It’s almost universal for these cameras to be held together with two screws near the film door hinge, and two more inside the film supply compartment. The screws are tiny, and all too easy to lose. Usually all four are the same size; but if yours don’t match, keep track of which went where.

With some trashcam styles, you can remove the front without removing the rewind knob. For others you’ll need to disassemble that too.

The camera pictured has a screw under its flip-up crank. In another common style, it’s between the prongs which engage the film cassette; you unscrew it from inside the film compartment.

The last obstacle to removing the front is often the rewind release button on the bottom of the camera. Click in the button (if you can); you may also need to gently pry the bottom of the shell outwards, to ease it over the button.

Loose Bits

Once you manage to take the front shell off, you might be greeted with a shower of unidentifiable plastic parts flying everywhere. Don’t worry, you haven’t wrecked anything! (But it’s a good idea to work over a towel or a tray, so you don’t lose something vital).

We’re in!

One loose part will be the shutter button. For safe keeping, you can put it back in place in the top of the front shell then tape across it to hold it there.

Also, a couple of lens-cover parts may have fallen out: A pivoting flap and a slider. (The slider has the finger-tab which emerges through the front of the camera.)

The slider often has three click-stop detents: one for closed, one for open, and one which allows it to be pulled out of the lensboard. The flap piece should have a hole which fits on a pivot post, and a peg which engages the slider.

Using my illustrations as a guide, take a moment to understand how the lens-cover parts fit together and operate . For your pinhole camera, this will be the only “shutter,” so it needs to be working properly.

(With a few camera styles, the lens-guard assembly is fastened to the front shell; if so, set the whole thing aside and ignore all this.)

If a wiggly, serpentine piece of plastic falls out, this is a spring which engages the back latch. Examine it and locate the small hook, which mates with a matching hook on the film door. This should help you re-orient it correctly. (Note the camera shown here has a different latch style.)

The last few parts which may come loose are the wrist-strap (eh—who needs it?), and possibly a clear plastic window from the film counter.

If you really do end up with a chaotic mass of stray parts you can’t put back together—don’t despair. Quietly put them into the trash, kiss your dollar goodbye, and start over with a fresh camera.

Lens and Shutter

Set aside your lens-cover parts. We’ve finally reached the tender innards of the trashcam—the lens, lensboard, and shutter. And we’re ready to rip out its heart!

It’s common for the plastic lenses in these cameras to be held in place behind a little retaining ring.

The ears of the ring click under two tabs on the front of the lensboard (arrowed). The ring can be removed by twisting (clockwise for this one) and pulling it forward, letting the lens drop out.

If your camera doesn’t look like this, the lens may be glued into place from the back of the lensboard. (To remove this style of lens may require some violence, like drilling or hammering a nail through it).

Removing the lensboard itself can be tricky: This is an area where the various cheapie camera designs differ quite a lot.

For some, you remove one clearly visible screw, and the lensboard lifts off some pegs. Another common style clips the lensboard in place with four plastic latches around the sides; these need a gentle touch with a narrow tool to pry each loose, so the lensboard can be worked free.

But the style shown here is the one most likely to stump you: besides one plastic latch to the right, it also uses a hidden screw—in a deep recess just below the shutter-button slider (left arrow). Unscrew that, and the lensboard can be pulled free.

We now reveal the original shutter blade, and its spring . Please take a moment to savor its low-tech ridiculousness. A little plastic finger flicks it open; the spring pulls it shut again. And yet somehow it works!

Up until this point, if you so wish, you could re-assemble your camera—restoring its original function in all its plasticky glory. But we’ve reached the crossroads. Next, we will begin trashing parts and carving into plastic.

And for that, we will continue in Part Two….