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Polaroid J66 to J610 120 Fully Manual Camera

This article covers the conversion of a Polaroid J66 we picked up at a local flea market into the J610. First was a conversion to use 120 medium format roll film followed by a full manual conversion. All of the research found online says you can’t make the J66 or J33 into a manual camera, but that’s not true at all.

J610: A Polaroid J66 120 Full Manual Conversion


We’ve taken some photos with the new setup and will be posting them as soon as the film is dry enough to scan. Of the two rolls we shot one of them turned out perfect. The first roll had some light leaks and didn’t feed correctly because we forgot to pack the spool holder. In order to fix the light leaks we packed some felt scraps around the bellows where they come out of the camera body. Apparently light was still making it past the sewn felt cover.

Click the image below to see samples from this camera. The first shot of Arvest was taken with Fujifilm Neopan Acros 100 and the remainder were Fujifilm Neopan 400 Professional. We’ll be taking more photos in the near future using a mix of Ilford and ADOX films.

J610 Manual Sample Photos

This camera was from one of the local flea markets for 6.50 in the Polaroid leather case. According to Land List the J66 is a common Polaroid produced from 1961 to 1963 with a 114mm f/19 meniscus (single-element) plastic lens. The shutter is a pneumatic rotary system rated at 1/15 to 1/1000. Upon noticing a rattling noise and opening it up this negative (converted to positive) was still inside the camera. It’s most likely the last image this camera ever shot for the previous owner.

Last image ever shot

That being said one of the first things we did after the 120 conversion was attempt to shoot some film. The following photos are two examples. First we have Nathan Crain of Nathan Crain Photography. You can see some light leaks on the right from pin holes in the bellows. The second photo is of Sarah Walter (soon to be Sarah Latus) and Robert Latus. The cropping is a bit off, but you get a general idea of what a photo would look like without leaks. All we did to fix the bellows leaks was wrap the bellows with black felt. Later we came back and made a sewn form fitted stretch cover out of black felt. It may not be fancy, but it keeps the light out.

Nathan Crain

Robert and Sarah

As you can see the images are quite long (or wide) at about 6×10.5 in negative size. Some people seem to like a 6×6 frame to get more shots and uniform images, but we just wanted the largest images possible. They are border-less, so you’ll want to crop the edges down a bit if you want them to be clean. Next up we’re going to take a look at the simple 120 conversion that we like to call the J610 due to the 6 by roughly 10 negative it produces.

J610 Open Back

J610 Thumbscrew

J610 Felt

J610 Lock Bar

The advance lever we ended up going with (after several failures) is a 1/4-20 Thumb Screw seated directly into the top of an empty plastic 120 cassette. Once you crank it down in there it’s not going to budge, but you’ll need to open the camera up in a darkroom to pull the film off the cassette after exposure. The bottom of the 120 cassette spins freely on a #10-32 bolt held into the body with a nut. On the left hand side where you advance the film from, we simply cut the old spool holder (held in by two small screws) off toward the bottom and put it back together with some electrical tape. A #10-32 bolt goes in from the top and bottom with a nut on each respectively. The tape and pulling the bolts back a bit allows you to easily feed in a fresh roll of 120. As for exposure we’ve figured out you can line up the arrow that goes from top to bottom to the far right. Advance the cassette and place the arrow directly over the right hand edge (to the left of the cassette you’re feeding it into). Closing the camera and crank the advance knob 5 full turns should put you into the first frame. After that advancing 2 and a half (2.5) turns should put you on the next frame. Advance it 2.75 if you’re paranoid about cutting into the last image.

Next up is how we managed to turn it into a fully manual camera. At first we simply wanted to replace the selenium cell with solar cells and a potentiometer to adjust ISO, but that didn’t work out very well. This process requires removal of the front of the camera. Once the bellows are extended you have to remove 3 screws from the back and once that comes off another 4 from the back of the lens assembly to split it in half. One of the 4 screws is the lever that locks your shutter into place when you cock it. It has a spring on it, but the spring is attached.

Once inside disconnect the red and black (or two wires if you have different colors) wires from the selenium cell. We don’t want it interfering with our new manual controls. At this point you’ll want to CAREFULLY bend the orange needle and the little meter bar so that the needle catches in the grooves on the bar. We have ours setup so you barely push it back to disengage and move from notch to notch. Each notch is a different shutter speed at F19 (providing you don’t use the front ring to darken it more). KEEP IN MIND that you can’t move the needle *unless* the shutter is cocked. Trying to do so will most likely BREAK IT. Now, put your camera back together and read on.

J610 Manual Control

Manual Control

Notches for Shutter Speed Adjustment

As you can see in the photo directly above this, the meter has notches in it that we have taken the liberty of measuring for you. Keep in mind that your mileage may vary, as your shutter may be faster or slower than the one in our J610. To test the shutter speed we placed a solar panel from a $1 LeWorld Dual Power Calculator (from Wal-Mart) on the end of a broken mono audio cable. Positive goes to the center and negatives goes to the outside ground sheath. What you do then is place the solar cell inside your camera up against the back of the lens facing out. You plug the cable into the sound card of your computer to record the wave that it makes when light passes through the shutter. We used a 4 AA flashlight placed directly in front of the lens to create our light source.

Solar Light Meter

Shutter Speed Sine Wave

This a very low tech approach, but as you see in the photo above you get a wave in the noise as light passes through the shutter. This specific image is from having the needle positioned all the way to the left (maximum shutter speed). Pulling into a program that shows more decimal places yields .0025 for the selected wave, which comes out to about 1/400 for a shutter speed. We believe the needle could be moved further, but would require greater modification than simply cutting out some plastic and bending a few things. You may also want to bend the end up on the arm you lock the needle into. We found the needle had a tendency to stick on the far left and be rather hard to dislodge.

The following is a list of speeds we registered from our J610 from left to right looking directly down on the camera from the top and behind it. (as seen above):

Position – MS time – Estimated Shutter Speed

1 – .0025 – 1/400

2 – .003 – 1/320

3 – .006 – 1/160

4 – .018 – 1/60

5 – .019 – 1/50

6 – .028 – 1/30

7 – .042 – 1/10

These are very usable speeds for most photography and allow the camera to be used at nearly any ISO you would want. We’ll also be posting our shutter speed cross-reference charts in the near future that we use on shoots. Using the charts you can quickly cross reference your digital camera meter reading to acquire an EV rating for your Polaroid (or any vintage camera). Once you have that it’s easy to find the correct shutter speed for proper exposure.

Also on a side note the shutter sensitivity can be adjusted by messing with the bracket on the left hand side of the camera. You can unscrew it, push it up a bit, and tighten it back down for a hair trigger.

Did you like this camera hack? Hate it? Don’t really know what to think about it? Leave a comment below.

Posted by falcoln0014 April 2010

11 Responses to “Polaroid J66 to J610 120 Fully Manual Camera”

[...] sent in this cool project. He has modified a Polaroid J66 camera to use modern film. Most of the initial modifications look fairly simple, but things get a little more complicated [...]

[...] sent in this cool project. He has modified a Polaroid J66 camera to use modern film. Most of the initial modifications look fairly simple, but things get a little more complicated [...]

[...] more here:  Psychotic Studios » Blog Archive » Polaroid J66 to J610 120 Fully … Tags: allison-mcvey, bellows, camera-hack, camera-mod, camera-shutter, conversion, fully-manual, [...]

[...] Psychotic Studios » Blog Archive » Polaroid J66 to J610 120 Fully … [...]

cade Says: April 17th, 2010at 10:20 am

Hey i like this conversion, it looks like the easiest so far. But im wondering, How do you get the roll of film developed? I guess you take it to the photo shop at Wal-Mart? I know originally this camera took film that developed with light. I just acquired a J66 but Im not real sure if I can convert it or not. Please help me out,

falcoln0014 Says: April 17th, 2010at 10:34 pm

We actually shoot traditional B&W film and develop it in a sink. The main problem you would run into getting it developed somewhere is getting your film back onto a roll and light tight. What we do after shooting the J610 is unload the film in a darkroom from the camera into a light safe canister for development. You can find plenty of tutorials on DIY B&W film development on Google if you’ve never done it before.

We’ve also shot and developed C41 color in the J610, but would not recommend it to someone that isn’t familiar with the traditional B&W process. It requires very precise control of the development temperature (in the neighborhood of 105F within a few degrees), or the results can be less than desirable.

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Joe Says: January 13th, 2011at 5:43 pm

Thank you for this good howto. I would like to do this conversion, but i have some questions: If i leave the selium cell system untouched (I think its no more working afer 50 years) what is the standard shutter speed used by the camera?

Its made for 3000 Film, how can it works with 100 or 400 film? Should i use Delta 3200? Thank you, Joe

falcoln0014 Says: February 25th, 2011at 12:45 pm

Try firing your shutter indoors and listen to the speed that it fires. Afterward, take it outside and point it toward the sun, fire it, and listen to see if it fires much faster. It should be pretty easy to tell if it still works.

Providing the selenium cell still functions at the same speed it was designed at you would be best using 3200 film. You could also shoot 800, 1600, etc and push process to 3200. The selenium cell is calibrated to operate the shutter based on ISO 3000 sensitivity, but since it’s old its probably a bit slower now. I would think you could test the sensitivity by doing a test similar to the one I used to get my shutter speeds, only in this case you would need a digital camera too. You could aim both cameras at the same light source and capture data from the J66. That would give you a definite shutter speed for a given light source and you could adjust the ISO on your digital until you had a similar shutter speed with correct exposure. You should then have a pretty good idea of the actual sensitivity of your J66 cell.

I believe by default the shutter goes to the slowest speed possible. From what I understand the selenium cell voltage drives the needle which directly controls air flow from the pneumatic piston. As the voltage climbs the shutter speed increases proportionately.

[...] the same shutter speed tests we used on the Polaroid J610, we came up with two different shutter speeds working on our Isolette [...]

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