HowTo: Converting a Polaroid Rollfilm Camera

Introduction:

Unfortunately, I ended up abandoning the project after a certain point as I couldn't find a way to perform a key part of the "surgery" without access to a more elaborate set of tools.

However, due to the consistent interest in this sort of project by visitors to this site, I figured I ought to do something to fill this void in the meantime. One thing: I took some photos during my original construction process, but seem to have misplaced them since then. Therefore the illustrations presented on this page are new ones that I (rather hastily) prepared after the fact for this document.

The following is not a complete set of instructions by any means, but should help out those who would like to try to attempt a packfilm conversion. You'll note that the part about mounting the back is a bit sketchy, since I never actually completed the project. Therefore, some steps may turn out to be unworkable. If anyone out there manages to complete a conversion, let me know. ...Especially if you can find an easier/better way to handle some of the issues involved. Any improvements/comments would be appreciated! Thanks.

IMPORTANT NOTE AND DISCLAIMER:

In addition, keep in mind that even if your conversion is a success, you cannot revert the camera to its original state should you change your mind in the future. Once you've made the conversion, it will never go back the way it was. This will become obvious as you read though this, but I just want to make sure this point is perfectly clear from the start.

OK, enough depressing (but important!) stuff for now-- let's look at the conversion project!

Project Overview

The procedures detailed here cannot be used with Polaroid cameras designed for 30-series rollfilms (the 80, 80A, 80B, and J33) or for 20-series rollfilms (the Swinger 20 and cousins). The smaller image size of these cameras does not correspond well to any of the pack formats.

This project is really intended primarily for owners of Model 110A, 110B, and 120 (Pathfinder series) cameras. For the purposes of this project, however, I chose a Model 150 as I didn't want to risk destroying an expensive 110A. [The 150 cost me four dollars at a camera show complete with leather case and Wink-Light...] The 150 has the same body, rangefinder, and focus mechanism as the 110A, so the conversion procedure should be essentially identical. You too may wish to do a 'practice run' with an inexpensive Polaroid camera model as well, or (for whatever reason) you may wish to convert one of these anyway, so a few tips:

• If your intent is to convert another camera as "practice" before doing a 110A/110B/120, I'd suggest trying it with a Model 150, 160, or 800. These all have the same basic body components and focus arrangements as the 110A/110B/120 Pathfinders (the 110B has a different rangefinder, but has the same physical exterior size/shape so shouldn't matter as far as the conversion is concerned).
• The focus stop on the Model 95, 95A, 95B, and 700 is pretty similar to the above cameras, but (on the ones I've seen, anyway) it is riveted in place and not adjustable. Therefore you won't be able to reset infinity focus nearly so easily on these cameras. In addition, the uncoupled rangefinder of the Model 700 is on the "wrong" side of the camera body, just as on the original Model 110, so the notes regarding that camera would also apply here. I wouldn't try converting a 700 due to the added complexity.
• The focus arrangement of the Model 850 and 900 is different from the other cameras, and involves a non-adjustable focus stop. Therefore, these would also probably be poor candidates for conversion.
• The J66 is very different from the other rollfilm cameras in this size. I wouldn't bother trying to convert this camera for several reasons, not the least of which is its limited range of usefulness from a photographic standpoint...

"What about the original Model 110 Pathfinder?" you ask. Well, as mentioned in the FAQ, the rangefinder on this camera is in an unfortunate location for the would-be conversion engineer. Frankly, I would recommend not converting an original 110, but if you're determined to do so anyway, there is a way to do it while preserving the function of the rangefinder. [I've seen one example of a converted original 110 at a camera show, but believe me, it was a real "hack-job"...] Additional notes about this will follow in the appropriate section. You might want to 'practice' on an inexpensive 95-series camera (which has the same basic body as the 110, minus the rangefinder-- but without the adjustable focus stop) first. Still, I think you might be better off trading in your 110 for a 110A or 110B and converting that instead.

A general outline of the problems/steps involved in the conversion plan is as follows:

1. Remove/disassemble the parts from the host camera that will no longer be needed.
2. Trim the remaining portion of the original camera back so that the new back can be mounted in place.
3. Mount the packfilm back to the camera.
4. Set and test infinity focus for the new back.

Preliminaries -- What You Need

• A rollfilm camera designed for Polaroid 40-series rollfilm to serve as the host camera for conversion (obviously!-- but see above)
• A film back designed for 100/660-series Polaroid pack film (see below)
• A tool capable of cutting solid metal (a hacksaw with a fine metal-cutting blade might work; a high-speed motorized hobby tool (i.e. Dremel Moto-Tool) with a metal cut-off disk might work; however something more heavy-duty than either of these would be preferred)
• A tool capable of cutting solid plastic (a hacksaw is fine)
• A tool capable of filing/shaping plastic (a Dremel-style tool is great for this, but hand files would work too)
• Various miscellaneous hand tools (screwdrivers, pliers, etc.)
• An empty Polaroid film pack in which you can mount a piece of ground-glass or a usable substitute (a sheet of tracing paper will work).
• A strong but light-tight adhesive/filler (J-B Weld or other metal-bonding epoxy appears to be best for this; black rubber sealant may also work; Liquid Nails or other construction adhesive might also work too)
• Safety goggles, work gloves, and other safety items related to use of the above tools.

The cheapest option (and therefore probably the most appealing to the hobbyist) is to cut the back off of a cheap old plastic non-folding pack camera. These are plentiful and easy enough to find at flea markets/yard sales/what-have-you for next to nothing in cost (about a dollar or two). Aside from getting a suitable 'junk' camera, though, this option probably requires the most effort from a labor standpoint. Details about choosing a camera and cutting the back will be covered later in this page.

The most expensive option would be to buy an OEM-style packfilm back from Polaroid or a service agency. I don't know how much an unmounted packfilm back costs these days, but I'd suspect it'd be around $100 in quantities of one. This would simplify the conversion from a labor standpoint (and probably look better than a back cut from an old camera), but I suspect that most of you out there wouldn't be seriously reading this if you felt like spending $100 or more on converting a camera. [But, hey, I feel the same way, so... :-) ]

The "lucky" option is to find a cheap scientific camera that has a Polaroid back, and use the back (which will usually be an OEM-style back) from that. The operative word here, though, is "cheap". These can be very expensive, but you can sometimes run into these sorts of cameras/attachments at hamfests or electronic surplus stores for very little money, as many types of these special-purpose cameras are now obsolete (often either because nobody uses instant film for that particular purpose anymore, or because the equipment the special camera was designed for is no longer in general use). If you do find something like this, make sure the back itself (minus any spacers, masks, and other hardware) is easily removable (i.e. held in place only with machine screws or other removable fasteners).

Assuming you're going with the first option above, continue on to the next step. If you instead are using an OEM Polaroid back via the other two options, you can skip the next step.

Step 1: Preparing the Packfilm Back

Still here? Okay, first you need a 'donor' camera. This should be a rigid plastic pack camera. I would not recommend using a folding pack camera for this purpose, because the thickness of the back will make it more difficult to get the film plane near where you need it to be. Also, I would avoid the earliest non-folding plastic cameras such as the Big Swinger and Colorpack II, since these use "spreader bars" rather than rollers for the development process. The rollers work much more smoothly than the spreader bars. Oh, one other thing-- do not use the back from a 'square'-format pack camera (such as the Square Shooter or Electric Zip), as these will work only with Type 87 or 88 film, and probably won't fit properly on your rollfilm camera anyway.

First, cut the T-handle strap off the back of the camera, since we won't need that anymore.

Now, take a hacksaw (or other suitable cutting tool) and cut the back from the rest of the camera. It doesn't have to be a particularly neat job, but try to make the cut as close to the back as possible. At least one reader has reported good results using a Dremel-style tool with a cut-off disc for this purpose-- this would probably result in a closer (and cleaner) cut.

Using a file (or, better yet, a Dremel-type motorized tool with a grinding stone and/or a rasp attachment), grind down the rest of the plastic so that everything is flush down to the film plane opening. The side where the latch and tab slots are located will stick up from the rest of the back; leave this alone and do not cut it down. Smooth out all the plastic burrs you may have made in the process so that you have no rough edges.

Carefully clean out all the resulting plastic chips and dust out from the inside of the back, and you should be done! Now you've got a film back all ready for your converted camera.

Step 2: Disassembly of the rollfilm camera

First, remove the long hinge pin on the side of camera near the hand strap. [TIP: You might want to unbuckle the hand strap and remove it so that it's not in the way while you work.]

To remove the pin, take a piece of stiff wire (a straightened-out large paper clip will do) and use it to push the hinge pin through the hole at one side. A pair of pliers can be used to pull the pin out the rest of the way once you've gotten it started. If you're having difficulty getting the pin to move, try repeatedly opening and closing the camera back while you put pressure on the pin with your stiff wire or pliers.

Once the pin is out of the hinge, you should be able to easily remove the entire outer back from the camera.

Now remove the inner back (the part with the pressure plate) in a similar manner by removing its hinge pin.

Notice how much lighter your camera feels now..? :-)

By the way, do not discard the outer back or hinge pin-- as you will see, you might want part of that later on.

Now, with the back of the camera still facing you, look at the larger of the two film spool chambers (it's the one on the left if the top of the camera is facing away from you). There's a big black plastic (or metal/plastic in some cameras) film holder in there that you need to remove. It's held in place by two or three (depending on the camera) screws. Be careful when you remove these screws, however, as there's a small spring and a pin which may leap out at you once you lift the holder from the camera. [You know that little piston that causes the camera bed to 'pop' slightly when you push the bed release to open the camera? This is how that spring and piston are installed.] Save the screws and the spring and pin, but you can discard the film roll holder.

Cut a small piece of sheet metal (cheap aluminum "flashing" from the hardware store is good enough for this purpose and easy to work with, but whatever you happen to have around is fine) and drill two (or three) holes in it for the screws you just removed. Re-install the pin and spring in their original location, and use the piece of metal to hold these two parts in place, attaching it with the original screws.

NOTE: In the photo, I've left the piece of metal bare to make it easier to see, but it wouldn't be a bad idea to paint it flat black first in order to minimize any possible reflections.

Step 3: Preparing the camera for the new back

This is also the "point of no return." So far, you haven't done anything to your rollfilm camera that can't be reversed. That's about to change right here.

Take your packfilm back and hold it against the back of (what remains of) your rollfilm camera, taking care to line up the film plane of the camera with the opening in the film back. See how the tab-slot side of the film back prevents you from making the two sides mate together..? Well, that's why (and where) we need to cut off part of the camera.

NOTE: Before you start to cut or file or do anything of that sort with your camera, be sure to cover the rear element of the lens (and perhaps the bellows as well) so that it will be protected from all those metal filings that will surely be produced as you perform your surgery. You can tape a piece of cardboard over the lens/bellows, but do not actually let the tape itself come in contact with the lens surface. One thing I also did while I was attempting to cut the back of my camera was to attach loops of masking tape (with the adhesive on the outside) to the area immediately around the cut. These loops of tape helped 'catch' the filings as they flew from the cutting disc. I think this technique is more suitable for use when drilling through metal, though, but you can try it if you want.

You have a few choices here depending on your skill level, the complexity of the tools you have available, and how neat you want the finished product to look.

The easiest method is probably to simply lop off the entire side of the camera at a 90 degree angle. However, I think the end result (on the cameras I've seen done this way, at least) looks rather ugly. However, if the only metal-cutting tool you have is a hacksaw, this might be the easiest option.

A nicer looking camera will result if you can make a miter cut instead. What you want to do make the cut at an angle which will leave the front of the camera entirely undisturbed. If you do this correctly, you will still have plenty of room to pull the film tabs, but the camera will look about the same as it originally did when viewed from the front.

One potential hidden 'gotcha' with the miter cut, though, is that you'll have to cut through the rollfilm back's latching mechanism, and this could foul up (or break!) your cutting blade. The obvious solution is to disassemble the latching mechanism first, but that seems to be easier said than done. If you remove the two screws near the latch (where the words "Make sure both sides lock" appear), you'll be able to free up part of the mechanism, but you still won't be able to remove it entirely. It looks like part of the camera body is removable in some way, but I don't know how. At least two readers have since performed the miter cut using only a hacksaw, and reported no problems with interference from the latch mechanism. [Plus, a hacksaw would probably be safer than a Dremel tool, so perhaps a hacksaw would be a better choice for this purpose anyway]

A third option is to make an L-shaped cut. This might not look quite as nice as the miter cut, but involves the least amount of material removal. You'll still have to cut through the latch, but it probably won't interfere as much with the cutting operation. I've never actually seen a camera done this way, but I think it's probably a good compromise.

Now, if you have an original Model 110, by now you should have seen that any of these cuts would go right through your rangefinder. To avoid this problem, the one original 110 that I've seen converted had the cut on the opposite side-- i.e. the side of the camera with the hand strap-- so that the pack film back would face the other way (i.e. mounted upside-down). This looked really ugly, incidentally, but I suppose it worked.

No matter how you do it, once you've made the big cut, try and test-fit your packfilm back again. The side of the film back with the tab slots and the latch should clear the edge of the camera thanks to the cut you just made.

But-- see that 'lip' along the top and bottom edges of your rollfilm camera? You will probably find that the sides of your new film back rides just along the top of those ridges, leaving a space between the camera's original film plane and your new film back. You're either going to have to cut or grind down that metal lip, or you're going to have to cut down/file the sides of the film back so it will fit snugly between them. [If anyone finds a back that actually fits between those ridges as-is, let me know...]

On my 'test' camera, I originally tried cutting down that metal lip, but gave up since I really didn't have the tools to do it effectively and safely. Then I tried cutting down the sides of the film back. This seemed to be a better approach, but will involve a lot more care during Step 4, since the sides of the film back are no longer light-tight. However, at least one visitor to this site was able to cut down the metal lip with a hacksaw rather than a Dremel tool, so you might investigate that. Cutting down the metal lip would be preferable to trimming the sides of the film back.

Also, you may notice that there's a thin metal 'guide' riveted on the camera's film plane. This also should be removed, but take care. You could simply cut off the bent-up sides of the guide with careful use of a Dremel-style tool and a cut-off disc. Ideally, though, you'd want to remove the 'guide' entirely. This can be done, but be very careful if you drill out the rivets, because those same rivets also hold the bellows in place. Take a look at Bill Donovan's construction notes (see the Gallery section) and you'll see how he handled this issue.

Notice that I'm sort of "waving my hands over" some of these procedures, since I haven't gotten far enough to try them myself. Some individual ingenuity may be necessary...

Step 4: Attaching the new film back

In addition, this would be a good time to make sure there aren't any sharp edges or burrs, and smooth them out if there are. Be sure to carefully clean out any and all metal filings and shavings that may be left inside your camera.

Now, how to physically attach the new back to your camera. Ideally, you'd use some sort of positive fastening system, such as machine screws. Unfortunately, that's more easily said than done, since there aren't any existing threaded holes anywhere on the camera that you might use to do this. If you have a good drill and a set of small screw taps, you could probably machine your own for this purpose, but this is probably beyond the range of most hobbyists. If you opted to remove that thin metal film guide entirely from the film plane, you can follow Bill Donovan's example and use a rivet gun to attach the new packfilm back using the original rivet holes that were used to hold the film guide.

However, Bill also made another suggestion which others have also had some success with-- and that is to use an epoxy designed for metal-bonding (specifically J-B Weld brand, but other manufacturers also produce these types of cold-weld epoxies). Even if you reinforce the bond with rivets or screws, you will need an adhesive of this sort to 'fill in' the cracks and make the seal completely light-tight. Besides 'cold-weld' metal epoxy, you might also try black rubber sealant (sometimes called "liquid rubber," I believe) or perhaps even construction adhesive (i.e. "Liquid Nails").

My original plan was to attempt to attach the film back using only black rubber sealant, but Bill's suggestion of J-B Weld makes a lot more sense. [At least one person has reported success using it for this purpose even without using rivets or screws to reinforce it!]

Step 5: Reset infinity focus

Ok, if you're converting a Model 110, 110A, 110B, 120, 150, 160, or 800, unfold the camera and look carefully at the camera bed as you pull the front standard out of the camera. When you get the front standard out to where it stops, it latches in place. Look carefully, and you'll see that this 'stop' is adjustable by two small screws. If you loosen the two screws slightly, you can shift the 'stop' back and forth a small distance. What you need to do is reset the position of this 'stop' to accommodate the distance between the camera's original film plane and the film plane of your new back.

First, you'll need an empty film pack. Take apart the film pack by unsnapping the metal piece from the back, and then remove the metal insert. All you'll have left is a rectangular plastic shell with a big rectangular opening in it.

Ideally, you would place a piece of ground glass just behind the rectangular opening, and load the film-pack-plus-ground-glass into the camera. However, a piece of tracing paper will also work; just cut it to fit in the film pack, and tape it behind the rectangular opening.

Take the film pack shell (with the ground glass or tracing paper attached inside) and load it into your camera's film back just as if you were loading a pack of film, but leave the back open. Set the camera's shutter to "B" (bulb), cock the shutter (if using a Pathfinder camera), and press the shutter release. You should be able to see an upside-down image on the ground glass. This will work best if you aim the camera at a subject that is better lit than your surroundings (especially if you're using tracing paper rather than ground glass). Since we're going to test infinity focus, doing this indoors with the camera pointed out a window is probably the simplest solution.

Now, while aiming the camera at a distant object (i.e. more than 100 feet / 30 meters away), set the camera's focus to infinity, and, with the two screws holding the 'stop' in place loosened, slowly move the camera's front standard back and forth until the image on the ground glass is in focus. Tighten the two screws in place once more, and you're done! If you can't shift the 'stop' plate back far enough to get proper focus, try removing the plate (by removing those two screws entirely) and lengthening the two oval-shaped holes to allow a greater range of movement.

BTW, you will probably want to do this with the camera mounted on a tripod, and a cable release would be handy to keep the shutter held open.

Step 6: Tidying up

First, there's that big void near the hand strap where you can still see the film chamber where the 'positive' film roll originally went. If you kept the original outer back and hinge pin around as I suggested rather than discarding them, you can saw off a small portion of the back and re-install this 'vestigial' roll back on the original hinge. The exact point of the cut will vary depending on the origin of your film back, but it should be somewhere just to the left of the film release switch. You'll have to measure the exact point on your particular camera/back, but you should be able to see what I mean. Especially with an OEM film back, the 'vestigial' rollfilm back will probably end up fitting just about perfectly flush with the back of the packfilm back-- very neat looking indeed! The only "catch" is that you have to make sure you can still 'open' this vestigial back-- watch what happens when you try to load film in the packfilm back; the packfilm back's hinge will bump against the 'vestigial' rollfilm back unless you open it first. The Four Designs converted cameras I've seen have a spring installed in this 'vestigial' back to keep it closed unless you deliberately hold it open.

Another potentially 'ugly' spot is the place where you cut the camera near the back latch-- now you've got a gap in the plastic trim plate at the top of the camera. Well, you can fill in this gap with plastic filler from the hardware store (this is generally sold for filling holes/gouges in wood, and is available in a variety of colors; find one that reasonably matches the plastic trim on your camera if possible), or you might be able to cut a matching chip off the part of the trim you had to cut from the camera, and glue it in place.

Whew!

For some more tips/hints, take a look at these conversion attempts done by other visitors to this web site:

• Bill Donovan's Model 800
• S|ick's J66

Likewise, if you discover a better/easier way to accomplish some of the steps described here, or discover an added complication specific to a particular camera or model, I'd appreciate it if you'd drop me a quick email to let me know.

Thanks, and have fun!

--Marty