Silverbased

Projects and ponderings for film photographers

Pimp my Polaroid, Vol. 4: Packfilm Mongrel

In 1963, The Polaroid company introduced a new system of 3.25″ x 4.25″ film packs. These are informally known as the “peel apart” pack films, since the print must be separated from the negative after a specific length of development time. The new emulsions included a 3000-speed B&W film which was startling for the time, as well as color types. These packs could be used in Polaroid’s accordion-folding amateur cameras; in professional modular studio backs; and in technical products like microscope and oscilloscope cameras.

In today’s dark times waiting for the End of Polaroid, pack film may be our one remaining bright note. Because Polaroid’s older patents have expired, Fujifilm was able to introduce a line of instant films that are drop-in replacements, fitting all the same cameras and backs. And better yet, they’re cheaper than most Polaroid options.

One of Polaroid’s peel-apart film types, number 669, is cherished for its odd color tonality and workability for emulsion-lift techniques—regrettably there does not seem to be any direct Fuji replacement for this. But otherwise, my early tests with Fuji’s FP-100C color packfilm seem promising. I have heard much praise for their B&W emulsions too, but have not tried them myself.

We can’t know how long Fuji will continue making these films, of course. But my speculation is that with their setup costs already paid and their only competitor leaving the market, Fuji’s packfilm will be the one remaining “Polaroid” material available in the coming years.

As I’ve complained before, most of the amateur-grade cameras sold by Polaroid itself were rather uninspired. Most featured slow, pedestrian-quality lenses and have no option for manual exposure control. Polaroid did make a handful of “professional” manual-exposure models like the 180 & 195; Or the 600SE (basically an adapted Mamiya press camera). But the relative scarcity of these models keeps their prices high on the used market even today.

However, the company produced millions of consumer folding models—all of which used essentially the same standardized film back and bellows assembly. Just start looking around at yard sales and camera swaps, and you’ll find numerous 100-, 200-, 300-, and 400-series cameras, generally at giveaway prices.

Polaroid Model 104

Polaroid sold many variations on this basic design; here a Model 104

Considering their ubiquity and low value, there’s no need to feel guilty about cannibalizing one for other purposes. Other possible lens-shutter combinations can be adapted to replace Polaroid’s original; all that’s needed is an image circle covering the 120mm print diagonal (or just close to it, if you enjoy some vignetting). People have even adapted Holga and Diana lens/shutter assemblies to work!

But to me, the main reason to make such a conversion is to gain full manual exposure control with true f/stop and shutter-speed settings; and perhaps to use a focal length never available from Polaroid’s own offerings.

In my stash of random optics, I had a nice 1961 Schneider Angulon lens in a Compur shutter (scored cheaply at an estate sale once). Its 90mm focal length would yield intriguing semi-wide coverage on the packfilm format (about equivalent to a 32mm lens on 135 film).

The Angulon’s f/6.8 maximum aperture doesn’t sound too exciting; but this still is an improvement on Polaroid’s typical f/8.8 lens. A bit of research told me that the 90mm Angulon formula (not “Super”) covers 4×5″ film—so on the smaller Polaroid format, there was even room for some shifts and swings if I wanted them!

Thus I resolved to build a home-hacked “field camera” based on an unused Polaroid model 420 I had been given. (Thanks Ralph!)

Polaroid 420 with Lens and Shutter Removed

I won’t repeat the excellent disassembly photos on this Italian blog, which apply to most accordion-style Polaroid models. But my first step was to remove the whole lens and shutter assembly. Because of the different focal length of my new lens, the original viewfinder and rangefinder became useless too, so I removed those as well.

The original lens on these cameras has a focal length of 114mm. To focus at infinity with a 90mm lens, I would not be able to extend the old lensboard and struts to their original locked position. So after a bit of hacking I extracted most of the strut parts too.

The front rim of the bellows includes a metal piece, whose opening needed to be carefully enlarged to accommodate the diameter of the Schneider lens.

Polaroid Bellows with Lensboard and Struts Removed

This camera was definitely a quick experiment. So to keep construction simple, I didn’t attempt to engineer any fancy collapsing lens mechanism myself. Instead my scheme was just to hot-glue a slab of plywood to the bottom of the camera; then mount the lens on a sliding standard made from a stiff ‘L’ of scrap aluminum. This does mean that the completed camera is a bit of an armful to carry around, though!

New Plywood Bed and Lens Standard

The height of the lens hole aligns with the center of the bellows; there is is a smaller hole at its perimeter, for a peg on the shutter which keeps the lens from spinning. I slotted the bottom of the standard so that when the camera was in the vertical orientation (e.g. shooting a building) I could shift the lens upwards for perspective control.

New Lens Standard and Bolt

As turns out, I was too conservative with my +/- 23mm of shift: The lens has enough coverage that I should have gone for more. I made it possible to pivot the aluminum standard, too, hoping this would be useful for focus control; but in my experience, the effect of this is pretty subtle, given the generous depth of field of the Angulon and the small print size. But if you were using a longer, faster lens, it might be useful.

The aluminum lens standard is simply glued to the front of the bellows with a generous bead of black silicone sealant (sold as auto gasket material). I used clothespins to hold those parts together until the silicone cured (with my nice lens removed, of course!).

The plywood is slotted for focus travel, with a wingnut on the bolt allowing fingertip loosening and tightening. The bottom of the plywood also includes my favorite homebrew “tripod socket”: A 1/4″-20 nut epoxied into a shallow hole.

The next step was to calibrate the focusing scale for different distances. To do this, I cannibalized an empty film pack and made a ground-glass back with it. The frosted surface is just sandpapered plexiglass; this needs to be glued tight inside the plastic front of the film pack, frosted side forward, to be in the correct film plane. (The metal pack parts are discarded.)

Film Pack Groundglass Holder

With that held into the camera and the back swung open, I measured off known subject distances and then used a magnifier to find the best points of focus on the groundglass. It turns out that the amount of lens movement needed to focus from infinity to 4 feet is surprisingly small. But conveniently, the extra bellows extension available permits focusing down to 2 feet or closer. (You can see where I’ve added marker lines on the plywood, corresponding to several measured subject distances.)

Plywood Bed with Distance Scales

Unfortunately a Polaroid film pack doesn’t have a dark slide; so you can only use the groundglass to set up the camera, not as a focus aid for each shot. Fortunately focus turns out to be fairly non-critical even wide open at f/6.8. Guessing at the subject distance has turned out to be an entirely adequate method of focusing this beast.

Finished Camera with Finder and Hood

There were a few finishing touches to the camera: I screwed a metal accessory shoe into the plastic body, salvaged from another camera carcass; it’s used for an auxiliary viewfinder approximating the correct semi-wide lens coverage. (No, that is not a VIOOH, you Leica geeks; just a cheap Japanese copy.) That finder actually has the wrong aspect ratio and inaccurate parallax compensation—but hey it’s better than nothing.

I also added a nice lens shade via a Series VI adapter; and trimmed the corners of the plywood so they’d be less likely to snag in the oversized beach bag I use to lug this camera around.

I must confess that the “tilt-shift” aspect of this project did not turn out to be as useful as I’d hoped. So it’s a bit hard to justify the bulk of the completed camera. Yet it’s a delight to be able to use an honest-to-god handheld light meter and conventional exposure settings with Polaroid materials. Here’s a sample from my trial of Fujifilm’s FP-100C packfilm. (It seems Fuji comes through with the greens again!)

Sample Anguloid Photo, Fuji Color Packfilm

I’ve nicknamed my Frankenstein creation “the Anguloid.” If you’re interested in more samples, check out my photos on Flickr tagged with that.

Sawing Expensive Glass In Half

A tip of the hat to friend Katrin for forwarding a great link to Wired’s gadget blog, with a look at some optics exhibits at the Deutsches Technikmuseum Berlin.

The museum shows several camera lenses cut open—one of which appears to be a Leica Tri-Elmar-M:

Leica Tri-Elmar-M, Bisected

I realize this museum is in Berlin, and thus wants to showcase Germany’s well-regarded optics industry. Still, it’s a bit heart-stopping to note that this particular Leica lens is now out of production, and was hardly an inexpensive item—one currently for sale on eBay has a “Buy It Now” price of USD $3,350!

This is an unusual lens for M-mount rangefinder cameras, that can be switched to 28, 35, or 50mm focal lengths. Note that it is not exactly a zoom lens, as only those three discrete focal lengths are available. (This makes sense on a rangefinder camera, where the viewfinder also switches between several discrete choices of frame lines.)

It’s actually rather impressive that the lens achieves this (and has a good reputation for sharpness to boot) with so few lens elements (8 elements in 6 groups).

If you were interested in my past post about simple camera-lens design, check out the link. The complexity that goes into sophisticated camera lenses can be pretty impressive.

Pimp My Polaroid, Part 3: Double-Exposures

Lately I’ve been telling everyone I talk to about my newfound, bittersweet fascination with Polaroids. It’s like learning that a loved one has a terminal illness—you want to savor as much of your remaining time together as you can.

As I understand it, the factory production lines for Polaroid film have actually stopped; what’s left is a few months’ supply still in the distribution pipeline. So I’ve been buying up Polaroid 600 packs whenever I come across them. (The best prices I’ve found are at Office Depot online; and locally—brrrr—at Walmart.)


But to stretch those last remaining shots, what better idea than to expose each frame more than once?

Most of the peel-apart packfilm cameras allow double exposures easily; and there is a known technique to trick Spectra cameras into shooting them. But for 600 film cameras, the only method I have learned about seemed complex and inconvenient.

But today I have a nifty camera mod which permits double exposures on 600 film—an inspired idea by my friend Allison Stanley. She owns a well-used Polaroid One600 camera, which sometimes failed to eject prints correctly. Appreciating the quirky beauty of her overlapping exposures, she suggested wiring in a “kill switch” to disable the print-eject motor at will.

I thought that idea was pure genius, and immediately wanted to try it out. It turns out that there’s a slight complication: All the 600 cameras I experimented with use the feed motor to recock the shutter too. But still, after adding the switch, a workable technique for 600-film double exposures does become possible.

Opening Up the Camera

The Polaroid One Step shown here is a typical 600 film model—easy to find for a few dollars at the thrift store etc. And this gray body-style with its flip-up flash is particularly easy to open: Its plastic shell simply snaps together. Let’s look.

Start by taking the flip-up flash and holding at about a 45-degree angle as shown. At this angle, it is possible to gently flex the side ears of the flash outwards and pop them free from the the camera body.

Lay the flash back on the top of the camera, out of the way as you remove the front panel. (But try not to put too much strain on that delicate ribbon cable as you go through the following steps.)

The front of the camera simply snaps into place; carefully insert a prying tool at the points shown by my knife and the red arrow; then ease the camera faceplate free. (The shutter button parts will fall out loose, so work over a towel or a tray so nothing gets lost.)

Here’s the opened camera, with the shutter-button assembly at left and the removed front panel at right.

Locate the ribbon cable which connects to the motor at the front of the camera. The conductors I’m pointing to are the ones that provide electricity to the motor. All we need to do is to cut through one wire and route it through an external switch, and the camera’s film-eject motor can be disabled as desired.

One flaw of that gray One Step above is that its electronic flash fires with every shot. Especially for double-exposures, I preferred not to risk washed-out colors by always using flash; instead I made the kill-switch mod to a vintage “rainbow” OneStep600 instead. But its disassembly needs a few extra steps. If you want to modify one of these, see the details here, then return for the other steps below.

Make the Hack

With small scissors cut through one of the conductors of the ribbon cable (the left side gives you more length of wire to work with). Then slice the clear plastic between conductors so you can pull the free cut ends outwards.

Prepare a small switch by soldering about 3 inches of wire to it. The type of switch isn’t important; but for ease of remembering I’d suggest orienting it so the contacts close when the switch is moved towards the front of the camera.

Drill a small hole in the side of the camera, into the hollow space under the photocell assembly. Thread the switch wires through this hole. Be sure to locate the hole far enough back so that the camera’s front panel can be replaced without interfering.

You could do a neater job than I did by mounting the switch inside the camera body; but I actually preferred mounting it in a sideways orientation where it would be less likely to get snagged and flipped accidentally. I glued the switch into place with hot-melt glue, adding an extra blob on the bottom to cover and insulate the solder tabs.

Cut back any excess length of the two wires, and solder their ends to the cut motor ribbon cable. The ribbon seems to be tinned already, so I found soldering to it surprisingly easy; but you do need to avoid jiggling the wires while the molten solder cools. (Forceps, etc. could be useful here to hold wires steady.)

That’s it!

Now it’s time to put the camera’s front back on. Be sure the lighter/darker control is centered so it will engage with the internal slider properly. I think it’s easiest to reinstall the shutter button parts by tucking them into the recess on the camera’s front, then sliding all the parts back into place as a unit:

Re-attach the flash pivots (again holding it at a 45° angle) and the camera is ready to use.

Using the Modded Camera

Okay, we’ll assume you’ve wired the switch so that when flipped forwards, the contacts are closed. In this position the camera operates exactly as originally.

Keep the switch “on,” and load a fresh film pack. When you close the door, the black cover sheet should eject. (If it doesn’t, something is wrong: Re-check your work.)

Remember, after every exposure the motor needs to run sometime, to re-cock the shutter and prepare for the next shot. But the switch allows us to delay that, and not have the print spit out immediately.

So the technique for double exposures is this:

• Flip the switch backwards, and make your first exposure (shutter fires, but print does not eject). I’d suggest that you slide the lighter-darker control all the way to darker for your first tests.

• Drop the film door open; then flip the switch forward (the motor immediately runs; but the rollers are disengaged so the print stays inside the pack)

• The front edge of the print (or as shown here, two prints) is pushed out of the pack slightly. Carefully push these front edges back into the film pack, as far as you are able.

• Close the door, leave the switch forward, and make your second exposure (print ejects normally).

• A third exposure (etc.) is possible by repeating the same cycle:

Switch off/shoot/drop door/switch on/tuck print into pack/close door.

There’s a couple things to note about this method. One is that pushing the front edge of the print back into the pack in daylight can leak light into the pack: This gives the funny “row of teeth” pattern seen at the bottom of this shot:

You can minimize this, by delaying the door-drop maneuver until you can move into dim light (or, push the print edge back into the pack by feel, with a jacket etc. thrown over the camera). But I’ve actually grown rather fond of this quirk.

The other issue is a general one for double-exposures: You can only add light, not subtract it. Any brightly-lit area of your subject tends to override the image in the other exposure. It’s mainly in the darker areas of the scene where you’ll see the double-ness of the exposure. So try to include sufficient dark, blank areas in your shots. And stick to simple, bold subjects until you get the hang of how images combine.

These are strange days, when the cost of a complete Polaroid camera is trivial compared to the preciousness of each exposure. Yet the freedom to cut up and re-jigger old cameras is liberating, too. And the magical serendipity of Polaroid doubles seems like a fine way to celebrate our farewell to this unique and irreplaceable medium.

Important Update: with most 600 cameras, making double-exposures will confuse the frame counter. After making 10 exposures (not after ejecting 10 prints) the shutter button will lock.

The slightly-inconvenient cure is this: grab a spare black film-pack cover sheet and go into a dark room. Open the camera, remove the film pack entirely, and slip the black sheet back into the top of the film pack. (Orient the little dangly plastic tag towards the cut-away corner of the pack.) Close the film door, and allow the camera to spit out the black sheet again (flip on the kill-switch if needed). The frame counter will be reset and you may continue taking pictures.