Silverbased

In an earlier post, I showed how to modify a Polaroid OneStep camera so that you could take multiple exposures onto 600 film. Lately OneStep cameras have become so cheap and ubiquitous at thrift stores and on eBay that this is a creative way to reuse a few.

Yet there are a couple of problems with the OneSteps. First, most models were very basic, plasticky, fixed-focus cameras, not offering much versatility. The second problem is that their frame-counting mechanism locks the shutter after 10 shots. If you’re shooting multiple exposures onto each frame, at some point you’ll need to remove the film pack in a dark room to re-set the counter, which is inconvenient.

Polaroid’s SX-70 models were much more sophisticated than the OneSteps. They featured a compact, collapsible body, a good-quality glass lens, and true SLR focusing all the way down to 10″. However they’re a bit tricky to disassemble, so the “kill switch” mod I described earlier would be rather complicated to try on an SX-70.

An SX-70—even a thrashed one like my white model 2—is a sleeker, nicer camera than any of Polaroid’s OneStep models.

But Flickr user amalia chimera called my attention to a YouTube video by her friend Brian (whose demonstration of double-exposures on a Spectra camera I had previously linked to). In a second video he shows a technique for fooling SX-70 cameras to make double-exposures possible.

Basically, the trick is this: An SX-70 has an interlock so that if the film door is open, the shutter and eject motor won’t operate. However by pressing the door-sensor lever with a narrow tool, you can take a shot even with the door open. Because the feed rollers are disengaged then, the print does not get ejected and developed. You can nudge the print back into the pack and make a second exposure.

An SX-70 does require an exposure adjustment to use 600 film. But that’s a minor problem. And I would much rather shoot with an SX-70 than a cheesy OneStep, so Brian’s technique really excited me. Plus, no permanent surgery to the camera was needed. So here’s a few refinements and additions to what Brian’s video shows.

Start by cutting a bit of kitchen match or barbecue skewer so that it’s exactly 41mm long. (I’ll explain the reason for the piece of tape later.)

When you open the camera’s film door, you will see a small, dull gray piece of folded metal on the left edge—directly below the plastic ribbon cable. There is a peg on the film door which rises up behind this when the camera is closed; it lifts a small black plastic lever. This is the switch we need to “fool” with our special tool.

By using a stick exactly 41mm long, we can brace it against the film door’s light baffle and keep the switch pressed upwards.

With the switch overridden, you can take your first exposure without ejecting the print. Because you might walk around in full daylight for some time before finding the right subject, there’s a risk of light leaking into the front edge of the film pack. If you’d prefer to avoid this, you can wrap the front of the camera with a shroud of black cloth, paper, etc.

Cloth shroud held in place with rubber band

One of the many clever features of the SX-70 is that any adjustment made to the lighter-darker dial would be reset to zero whenever the camera was folded. However you will probably find your double exposures will look too washed out if you don’t set the dial towards the darker end of the scale before shooting. It’s a slight annoyance that you have to remember to do this every time you open the camera.

Remember to turn the exposure dial towards the black!

When you take your first image, about 1/8″ of the print edge is shoved out of the film pack. Ordinarily this would feed it into the rollers, which spread the chemical goo inside the print and start development. But we’ve prevented this.

It’s extremely important that you shove the print edge as far back into the film pack as possible, behind its flexible plastic light shield, until no more white is visible. Otherwise you run the risk of the camera ejecting two prints at once, spoiling both. But the wood stick we cut turns out to be a handy tool for nudging the print back into place.

Try to go somewhere in dim light before shoving the print edge back into the pack, since this is the stage where you’re most likely to flash the bottom of the image with light leaks. But I’ve become kind of fond of the “row of teeth” light effect you sometimes get from this (seen in the sample image below).

Now close the film door and shoot the second image. As I noted last time, any bright area in your subject tends to blow out whatever detail might have appeared in the other image. Experiment with leaving lots of dark, blank areas in the frame to give the clearest “double-iness” to the final photo. The SX-70’s extra-close focusing can help you isolate simple and uncluttered subjects.

A happy discovery was that an SX-70 does not lock the shutter after 10 exposures (at least, my Model 2 doesn’t). The frame counter goes down to 0 shots and stays there; but you can keep on clicking until all the prints in the pack are used up. But it’s up to you to keep track of the correct count, of course.

Remember that piece of tape wrapped around the stick? Here’s one more tip: You can always keep your double-exposure tool handy by taping it under the SX-70 viewfinder hood. There’s enough space at the back end to allow the viewfinder to fold normally; and the stick won’t get lost this way.

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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 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!)

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.

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!

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.

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.)

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.)

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.

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!)

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