Fujica GL690 Panoramic conversion

[Murdoc1905]

Hello all, I got really interested in panoramic film cameras after seeing an Xpan on a photo walk. I've also always wanted a medium format camera but was always daunted by the modular nature of most standard medium formats. So deciding to mesh the two ideas I landed on the Fujica GL690. I was a bit surprised to find that the 35mm film Panorama situation to be extremely cumbersome despite having a very 35mm film style of loading the 120 rolls. The fact that you have to either dark bag it for every 35mm change or do the odd method of using a 35mm canister on the take up side then scrap the last shot of film was irksome to me. So I've set out to design and test a standard method (with hopefully minimal complicated steps) to get the standard 35mm experience where you shoot the film as normal, then you roll it all back into the 35mm canister and pull it out and swap it. Planned modifications to the camera are planned to be very simple, minimal, and completely reversible. It will require a custom 120 to 35mm spool and the replacement of the bottom spool lock/unlock lever which is held in place by a standard flat head screw that's left hand thread. Currently I have designed the pieces and sent them off to a 3D printing company to get 2 prototypes of each piece made for testing and fitment checking. Once the pieces come in it will be easier to show photos of exactly how things should work and the theory behind it. But basically the custom take-up spool is slightly shorter than a standard spool with a locating "bumb" on the bottom to keep it centered on the lock/unlock lever.

So with the camera closed you turn the lock/unlock lever to unlock which causes the spool to drop away from the film advance lever cam which will allow it to spin freely. On the other side the lock/unlock lever will be replaced with a different assembly that doesn't have a lock but can spin freely and for now is just a simple thumb screw version for testing purposes. So once you unlock the take-up spool you can then turn the thumb screw to pull the film back onto the 35mm canister.

 

[Alpsman]

Even though I don't have a GL690, but a GSW690, this sounds very interesting.

When I spool from one KB cartridge to another, the resistance is so great that I'm afraid of breaking something.

The left-hand threaded screw is under the black cover, I assume?

 

[Murdoc1905]

Even though I don't have a GL690, but a GSW690, this sounds very interesting.

When I spool from one KB cartridge to another, the resistance is so great that I'm afraid of breaking something.

The left-hand threaded screw is under the black cover, I assume?

I opted for a bit more reinforcement as long tear I wouldn't want to trust just a screw to take the brunt of twisting the film back into the canister so I went with a simple keyed shaft. Thou due to how small these parts are there isn't a lot of "meat" left in the lower section of the winder. Thou that is what prototyping is for. I do want to come up with a more elegant solution than just a thumb turn knob sticking out the bottom of the Camera but for functionality testing this will work.

 

[Alpsman]

For rewinding:
How about a kinda butterfly key which can be taken on and off and stored on yer keychain?
The rewind crank of a dismantled camera?

 

[shawn]

Cool project. Have you shot 35mm in the GL690? I did in the GSW690 and it took some extra work for the film spacing to be correct as there wasn't enough friction to turn the roller. I haven't tried it in the GL690.

You might want to consider a 3d printer, it will likely end up saving you money in the end. Prototyping often takes a bunch of versions. A small enclosed model that can print ABS or Nylon would be good. ABS is really handy as you can print parts in pieces (to avoid supports) and chemically weld them together to be at least as strong as the printed part.

Couple of thoughts. Is the shaft on the rewind knob long enough so it can slide down too? If not how will you load film? If so what is keeping it up when taking shots so that the film position doesn't shift while shooting?

For the screw in there it looks like it would be a tight fit but you might consider trying to add a heat set insert for the screw to grab into. Makes for a stronger connection that can be assembled/disassembled more without issue. Might have to go from the head inside the camera and screw into the thumbscrew. With a hex head you should be able to assemble that OK. That would also give you more room to make the key longer into the thumbscrew without having to leave space for the screw head.

Are you looking to have a little play on the takeup side? On my GL690 dropping the spacer isn't enough to unlock a regular 120 spool from the winder. Might need some way of helping drop that spool too to keep it unlocked from the winder. The bottom down there isn't magnetic unfortunately as I was thinking a couple of small magnets in the spool might work. Maybe a smallish spring that has a larger diameter than the winder key? That might also keep any extra play from letting the film shift during shooting.

 

[Murdoc1905]

For rewinding:
How about a kinda butterfly key which can be taken on and off and stored on yer keychain?
The rewind crank of a dismantled camera?

That could certainly be a solution, if I can I'll try to make it integrated as it's just simpler. But if I can't thats probably the most simple solution

 

[Murdoc1905]

Cool project. Have you shot 35mm in the GL690? I did in the GSW690 and it took some extra work for the film spacing to be correct as there wasn't enough friction to turn the roller. I haven't tried it in the GL690.

You might want to consider a 3d printer, it will likely end up saving you money in the end. Prototyping often takes a bunch of versions. A small enclosed model that can print ABS or Nylon would be good. ABS is really handy as you can print parts in pieces (to avoid supports) and chemically weld them together to be at least as strong as the printed part.

Couple of thoughts. Is the shaft on the rewind knob long enough so it can slide down too? If not how will you load film? If so what is keeping it up when taking shots so that the film position doesn't shift while shooting?

For the screw in there it looks like it would be a tight fit but you might consider trying to add a heat set insert for the screw to grab into. Makes for a stronger connection that can be assembled/disassembled more without issue. Might have to go from the head inside the camera and screw into the thumbscrew. With a hex head you should be able to assemble that OK. That would also give you more room to make the key longer into the thumbscrew without having to leave space for the screw head.

Are you looking to have a little play on the takeup side? On my GL690 dropping the spacer isn't enough to unlock a regular 120 spool from the winder. Might need some way of helping drop that spool too to keep it unlocked from the winder. The bottom down there isn't magnetic unfortunately as I was thinking a couple of small magnets in the spool might work. Maybe a smallish spring that has a larger diameter than the winder key? That might also keep any extra play from letting the film shift during shooting.

Yeah the friction issue will be resolved by some tape, I've heard "self sealing silicone tape" to be simple and effective.

I was thinking about 3D printing but I'm afraid with the size of these parts I'll be printing 3x the parts just trying to get it to the right tolerance. The company I'm going with right now it only cost $30 for 2 sets of those 3 parts shipped. Which isn't too terrible. Their tolerance is +/- 0.005.

The rewind part is exactly the same dimensions as the original with the addition of a key to be able to turn the film and a shaft key to avoid stress transferring to the small screw.

The size of the threaded hole is 0.070 in so there's not enough meat for anything but threads. Even with that it will still be challenging with the key removing more material

On the take up side I made the spool shorter than a standard spool, this will take some adjusting probably for tolerances as what might work on mine won't work on every camera right off the bat. My initial design idea was way over complicated but my concern with this one is the spool just won't drop as the spool will be held in place by the film or if it does drop it might scrape on something as it's wound back up

 

[Alpsman]

That could certainly be a solution, if I can I'll try to make it integrated as it's just simpler. But if I can't thats probably the most simple solution

Or a foldable butterfly.
The more you think about it, the more ideas you get.

 

[Alpsman]

. . . I did in the GSW690 and it took some extra work for the film spacing to be correct as there wasn't enough friction to turn the roller. . . . .

I tried two options.
The first was to mount a halved 135 film on the backing paper. It's a bit fiddly in the dark, but it works.

The second was to stick one (1) layer of silicone tape over the shaft in front of the take-up spool, which drives the film counter. (Normally this shaft is driven by the backing paper.) This gives the film enough friction to turn the counter roller and activate the counter.
I used this one, and it worked, too.

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>>self-fusing silicone Tape<<
I found this tip somewhere in the vastness of the internet.

 

[Murdoc1905]

As is the law of things, the parts were shipped the day before I left for a week and a half long trip and arrived the day after I left. So once I get back on Thursday I'll be able to check the parts out. I was also thinking of trying to make a 3D printed part of a sprocket that would fit around the counter shaft but I'll have to look into seeing if it can be done.

 

[OlivierAOP]

Just a note. Some medium format cameras have a clutch of sorts on the counter shaft, which would prevent rewinding. The GW690 seems ok in that regard but you should check on the GL to be sure.

If you increase the diameter of the counter shaft (via tape or sprockets) this will increase the space between frames. Probably not enough to matter.

 

[Murdoc1905]

Just a note. Some medium format cameras have a clutch of sorts on the counter shaft, which would prevent rewinding. The GW690 seems ok in that regard but you should check on the GL to be sure.

If you increase the diameter of the counter shaft (via tape or sprockets) this will increase the space between frames. Probably not enough to matter.

The counter shaft seems to turn backwards without resistance in both S and R mode, only difference I noticed is the displayed shot will roll back to the "start" of the last shot but won't continue to roll back further. Shouldnt be an issue but if it is ill just switch it to S mode and it should do fine. but I'll keep an eye on it when I do my tests with film if I'm able to.

 

[Alpsman]

Just so you can imagine what it looks like when you run 135 film through a Fuji GSW690.



The film is Tri-X, the film strip was cut in half and mounted on backing paper in a dark bag. Yes, it's a fiddly job. Even though the film was mounted at the original starting point, the first frame was only half exposed, and there was still enough film left at the end of the roll. Whatever the reason may have been.

 

[Murdoc1905]

Got the parts and everything worked remarkably better than I expected not perfect but the proof of concept is definitely there.



The only issue that I've seen so far is the tolerance on the upper spool is a bit tight so it grips the winder and doesn't release when I want to try to re-wind it. Will definitely make that larger but the other issue is the spool dropping after wanting to rewind it. The issue being the film wants to hold the spool in place but I want it to drop. It's possible to add a spring to assist in dropping the spool but it has to be weak enough not to overpower the lower spring that holds the lock in place.


The 3D printed winder part is a little flimsy but I'd wager that it would be perfectly strong when made from aluminum. As expected the winder knob does function but is a bit ugly. I'll give it a try and see how it operates.

 

[Murdoc1905]

Found the first snag camera wise, turns out the counter does not like being spun backwards when the counter is on S. Was a simple enough fix and this shouldn't be a deal breaker as long as photos are taken before it's rewound. I believe this happened because I was using my hand to rewind the counter spool when it was in S mode which caused it to unthread. I bet film would just drag across it if the counter spool stopped. Not ideal but not the end of the world.

 

[shawn]

Found the first snag camera wise, turns out the counter does not like being spun backwards when the counter is on S. Was a simple enough fix and this shouldn't be a deal breaker as long as photos are taken before it's rewound. I believe this happened because I was using my hand to rewind the counter spool when it was in S mode which caused it to unthread. I bet film would just drag across it if the counter spool stopped.

Maybe not when you add silicone tape to the spool to add friction.