Polaroid Film Conversions

This will require one Instax wide camera and one metal bodied Polaroid pack film camera. The Polaroid camera should have the extra exposure settings which allows it to be set for 300 ASA, so that metering with Instax film is possible. It may be possible to use any camera by setting it to 3000 ASA and using a 2 (or 3) stop ND filter over the electric eye. I found that exposing with the 300 ASA setting is pretty close since these cameras are getting old and often need exposure compensation of 1 mark toward lighten anyway because of the aging electric eye. Or, you can convert this camera to manual shutter capability. An overview of the upside down conversion is described in this video. An overview of preparing an Instax 100 to be used as a back is shown in this video.

You can mount the Instax wide back upside down or right side up. Regardless of the method, you will need to start by getting the Instax wide camera ready to use as a back.

Preparing the Instax camera

This operation involves taking the Instax camera apart and removing the electronic guts, leaving just the motor, gears, and rollers. If using an Instax 100, the lens body needs to be cut off with a hacksaw blade or other tool. The lens body on a 210 is not attached to the back, so won't need to be cut off. Because motor run-on is a problem with Instax wide drivetrains, previous instructions detailed reducing the time the cycle switch is on. New instructions on how to wire the back with a relay which prevents run-on is detailed below.

Wiring the Instax back:

A 6v relay is used to prevent motor run-on which will eject the whole pack of film if the cycle switch is wired in series with the battery. The relay shorts out the motor when turned off, instantly stopping it.

Wire the back according to the wiring diagram below, using a 6 volt relay using the schematic provided here
The carbon dot under the rubber shutter on an Instax 100 is replaced with a piece of aluminum foil for a better contact. The Instax 210 has a microswitch for a shutter button and needs no modification.
Solder a wire onto the appropriate battery terminal depending on the voltage requirement of the camera. Check the comparison chart to see what voltage your camera needs. Run this and the negative wire outside the camera.
Attach the back of the Instax case to the back and run the battery leads to the front. Place a piece of craft foam over the rollers protruding down so it clamps against the camera when mounted to prevent light leaks.

The Right Side Up conversion

This conversion is easier to do but winds up being thicker (around 15mm) than the upside down conversion. It also requires access to a 3d printer, but it doesn't require any cutting of the Polaroid frame. It also retains the use of the tripod socket. You will need to get and print the 3d files for this conversion since it needs various pieces to complete it. You will also need a single AA battery holder, some wire, solder iron, a momentary switch for the eject button, and some small screws as well as basic tools.

Remove the back by drilling out the 4 rivets holding it on. Remove the contents of the battery compartment and trim the wires going to the lens body. Remove the door latching mechanism by unscrewing it and sliding it out.
Put the spacer into place and tape the edges with hockey tape to help prevent light leaks
Cut the last battery bay off of the Instax wide back and solder a wire from the last battery terminal to a lead to the Polaroid battery compartment (to the right of the picture). Run leads from the battery terminals as well as the cycle switch along the bottom to the right of the back as well. A single AA battery holder will be needed to compensate for the battery bay removal which will be installed into the Polaroid battery compartment. Power for the Polaroid camera will come from the Instax back. Be sure to solder a lead to the correct terminal for either 4.5 volts or 3.0 volts, depending on your camera model.
Cut a 2mm piece of closed cell black craft foam to size to act as a light seal between the spacer and the Instax wide back and glue it into place with contact cement
Mount the Instax back onto the Polaroid with 3 pieces of tin, which can be cut from a tuna can, or an old SX-70 film pack spring. The first mount screws into the upper right side of the back and into the upper right side of the camera. Predrill the holes and self tap them carefully with small screws. Press down on the back while screwing it in to provide a light seal.
The second mount screws into the left side of the back and into the bottom of the battery compartment, where the door spring used to be. Be sure to press down on the back while pre-drilling the holes.
The last mount is on the bottom. Screw the metal tab into the camera first, then into the Instax wide back while pressing down.
Remove the rangefinder, then glue the focus tab extender onto the focus tab.
Mount the rangefinder onto the rangefinder platform and while moving the rangefinder cam over to the left, mount it where the rangefinder used to be. I ended up screwing it into place. I also ended up putting a small magnet onto the platform so the rangefinder would stay up and in place. Check to be sure that focusing operates the rangefinder correctly.
Mount the 21mm lens offset struts to the lens body with a 3/16" rod, then attach the scissors to the struts.
Mount the right strut to the bottom of the lens body and horizontal strut
Attach the single AA battery to the leads to provide 6 volts to the Instax wide back, and attach the appropriate voltage to the Polaroid camera lens circuit. Attach the eject switch in a place where it won't be activated by mistake. I placed mine under a piece of hard foam so it would be a little bit difficult to press.
Glue the case bottom onto the case, then drill the hinge off of the original front cover and trim off the supports holding the cold clip/instructions retainer, then glue/rivet it onto the 3d printed case while it's in place
If you have a 100-300 series Polariod camera, glue the flash extender onto the top right of the camera.
The case should stay closed by friction with the top nut of the strut. It may need to be filed a bit to fit.

The Upside down conversion

This is a more difficult conversion since it requires extensive cutting to the camera frame. This will make the camera more compact, but the tripod socket won't be available.

The back of the camera is removed by drilling out the 4 rivets holding it on. The battery chamber is removed and the wires trimmed (they will be connected to the Instax battery later). Remove the front of the battery compartment. Remove the bellows from the body of the camera. You can remove it from the lens body, but be sure to cover it while cutting the camera body.
Although you can move the lens body back by preventing the scissors from opening fully, I would recommend moving the lens body back with spacers. This is the best method, though it won't allow you to close the camera down into its case, since the viewfinder won't completely fold down. But it allows the use of the portrait and closeup attachments without being concerned whether the rangefinder is accurate or not. This can be done three ways. One method is mount the Instax back 18mm behind the original film plane and move the lens body behind the vertical strut. See these instructions on how to do that.
Or, you can mount the lens body back a lesser amount and to the side, which helps compensate for the back being over to the left of the camera. This works if your focal plane offset is around 12mm, but makes the bellows crumple a bit. As in the itype film conversion, cut 2 tabs and drill them with 2 3/16" holes the correct distance apart (around 12mm), a little more than the distance from the film plane to the instax film plane. This is tricky, because if the distance is too short, the vertical strut will be in the way of the shutter release.	.
Cut another tab for a spacer on the left side of the horizontal strut and screw it into place. Make sure the lens body is mounted straight onto the horizontal strut.
A third method is to use 3d printed struts to provide around a 7mm offset while giving access to the aperture controls. This is the method I eventually used since I was able to mount the back with a 7mm offset. Download the strut files here, print them up, and first mount the vertical strut by putting a 3/16" rod through the strut and lens body, inserting the horizontal strut into the vertical strut peg, then screwing the ends to the focus scissors.
Put the focus scissors into the slider, then mount the horizontal strut on the bottom of the lens body using the recessed screw hole
Cut off the left side of the camera leaving just the top curve. The ridges on left and bottom sides are cut off so the Instax back can be mounted as close to the film plane as possible. And the bottom plate is cut to the tripod socket to facilitate mounting the back. I used a hack saw blade to do the most of the cutting, and a file to finish. I found a hack saw cuts much faster than a dremel and doesn't get the body as hot.
Cut a notch in the lower left hand side of the camera to make room for a random gear on the Instax back. Line up the back to the camera to see what needs clearance and how much needs to be cut away.
Trim the lower left scissor guide to make room for the Instax back. Be careful not to cut too close to the guide slot.
Cut craft closed cell black foam to to fit inside the Polaroid film area and cut a hole the size of the Instax film. The foam I had is about 2mm thick, so I cut three sheets to stack between the Polaroid and the Instax back. The last sheet is cut bigger, making it protrude out of the bottom of the camera to provide a light seal between the rollers and the outside world. I found I had to mount the back at the bottom left edge of the film plane. Since Instax film is the same width, but 1/2" shorter than Polaroid film, this means the picture will be what appears in the top right of the viewfinder. The image will be cropped a little on the left, and about 15% on the bottom.
Lay the instax back onto the back of the camera to check the fit. You may need to add a layer of foam or do finishing touches on mating surfaces.
Flip the camera over and check to make sure the instax back is lined up similar to as shown. It should be near the bottom, over to the right a bit.
Cut a wide tab from a tin can and predrill 2 holes into the side of the camera, mounting it with 2 screws.
Mount the instax back onto the camera, being sure the wires from the battery compartment are not pinched and are led to the outside of the camera. Press down onto the Instax back while predrilling holes into the instax back and inserting the screws. Press down hard enough for a good light seal, but not too hard so the back is pressed to far towards the film plane.
Cut another smaller tab to attach the upper left hand side of the camera to the back. Predrill all holes, mounting the tab to the camera before mounting it to the back while pressing down on the back.
Cut a longer tab and wrap it around the scissor guide at the bottom of the camera and screw it on. While pressing down on the camera, wrap the tab around the instax back and screw it to the back.
Attach the leads from the Instax battery to the leads going to the lens body. Use shrink wrap and don't make the leads too long, as they need to be tucked into the side.
Trim the back door to the correct shape to fit around the back. Try to keep the latching tabs on the back with the tab door intact (it may have to be glued once you cut one of the rivets). This will allow you to latch it onto the back using the door latch. This step takes a lot of time trimming it just right and making the locking tabs engage with the latch mechanism on the camera.
Mount the door trim onto the back. You may need a small piece of tape on the upper left arm of the trim to keep it in place.
Remove the focus knob on the left side of the camera, trim it, and remount it upside down. Fill in the gap below it with a piece of trimmed battery compartment.
Here are all the pieces left over from this build. Save these pieces in case yor do more camera hacking and you need various bits and parts to fill things in.
The case will need to be trimmed for it to close over the lens body. This is the same procedure as trimming the case for the itype film conversion

Counting the exposures can be done with a piece of paper with 10 tabs cut into it, taped onto the back or inside the case. One tab is ripped off when a photo is ejected.

There you have it! A Pola Instax camera in 33 easy steps! Contact me if you'd have questions or would like to share your build.