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Uneven take-up in Arri 416 mag

arri 416 16mm magazine

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#1 Kalle Folke

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Posted 10 July 2015 - 04:59 PM

Hi all,

After starting out my "follow the 16mm dream" journey with a Arri Sr2 one and a half year ago I've now reached the wonderful position to own both a Aaton A-Minima and an Arri 416! Now nothing can stop me spending (loosing) money on personal projects that will go on forever… but every roll is a joy and a great learning experience!

 

Today I encountered a problem with one of the magazines (or with my loading of it maybe?). The film was taken up unevenly and eventually started scratching the sides of the take-up chamber. It made a noise that was quite unusual for the normally super quiet camera. When looking (feeling) for the problem in the changing bag I noticed that the film was cone/wave-like. I tried to even out the film and loaded the mag on the camera once again. After some meters of shooting the sound came back and I unloaded the exposed film. I evened the roll again when putting it in the can. Maybe that will cause scratches on the film?

 

It's only the fourth time I load these magazines so I may have done something wrong that didn't create enough tension. One thing I've noticed is the the lay-on roller arm isn't touching the film and core straight away. There's a small screw that keeps it from coming all the way down. After some more film has rolled up on the core it does engage (or how to explain it). This screw functions like this on all my three mags, and from what I can tell from videos and pictures online this is the way it should be, so not sure if that could cause the problem.

 

The film I used is a expired Fuji Eterna 400T that has been in the fridge at my local lab before I got it. It did feel a bit loose when I loaded the feed side also, can this have anything to do with it's age?

 

I'll keep testing to find out more, but I only brought this mag with me now, so can't compare and test the other mags yet.

 

Anyone who can think of a logical explanation and a solution? 

 

Thanks!


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#2 Kenny N Suleimanagich

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Posted 11 July 2015 - 05:10 PM

Could you post some photos of what you mean? 

 

Fuji is sometimes wound less tightly than Kodak. You can remedy this when loading by “twisting” while holding at the core. 

 

I think you might just been spooling the take-up incorrectly. I’ve never had this issue with my 416. 

 

You really need to “click” down the take-up core. It takes a bit of effort to get the hang of. 


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#3 Kalle Folke

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Posted 14 July 2015 - 04:22 PM

Hi Kenny,

Thanks for taking the time.

 

I've attached a photo of how it looks when the take-up side is ready to be closed. You see the small screw that prevents the lay-on roller to touch the core. But seems strange if this should not be how it's designed since all my mags are the same.

 

The scratch noise from the mag started after around 200ft (60meters). Before that it (the film) must have move up and down on the take-up spool.

 

Please explain more in detail how you mean I could tighten the roll when loading. Do I twist the whole roll of film in the direction that tightens it? Wouldn't that create scratches and maybe some kind of static tension (or what to call it, english is not my first language…)?

 

I'm sure I "clicked" the take-up spool down as far as it goes.

 

How do you mean " spooling the take-up incorrectly"? 

 

​I followed this youtube video of how to load the magazine:

 

It's a bit less detailed then the manual and I may have missed some important small detail? One thing that maybe makes the film loose in the transportation chain is that I advanced the film with the spool instead of pulling the film by hand when getting it to catch on the first wheel with sprockets (pins) on the take-up side?

 

I guess this is maybe better to try to solve by hands on testing… but I haven't really had a good opportunity yet, so I'll try with some theory first to avoid missing some important aspect.

 

I'll reload whats left of the roll and try again. Only problem is I don't have anything I want to film right now… and I try to combine all my camera tests with b-roll gathering for a documentary.

 

Thanks again!

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#4 Gregg MacPherson

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Posted 14 July 2015 - 05:19 PM

Hey Kalle,
I don't know the 416 but untill one of the camera technicians answers there are some generic thoughts that may be useful.

- If you are unfamiliar with a mag type you need to practice loading with expired junk film many times untill you are familiar and are sure the mag is good. Double perf is good for this, no rewinding needed.

- Run the junk film with the mag doors off to check everything. You will see or feel with your fingers if the tension is OK on the take up and what is happening with the roll as it takes up. But maybe the 416 with the mags open will give an error message and not run. (Laughs)

- My guess is that the friction clutch on the takeup needs service. Do you know when the camera was last serviced? The take up friction/tension is routine with that. Should be a cheap thing to fix. If you can freez the take up sprockets with your fingers and turn the take up spindle you should feel some friction. There will be an allowable range for the torque. If you know your high school math you could measure this torque yourself.

- That screw that stops the take up idler arm from properly closing towards the roll is wierd, but Arri must have a reason to do it. One can check that the idler roller has closed to the roll after a few turns of film.

- Is there any chance that your take up roll is not properly anchored to the core? You will see that in your test with the doors open. You can fix the film to the core with a little reverse fold, even reversing the core so it's an accute angle if you need to.

Edited by Gregg MacPherson, 14 July 2015 - 05:25 PM.

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#5 Kalle Folke

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Posted 16 July 2015 - 02:11 PM

Hi Gregg,

Thanks for you input.

I bought the kit from Arri rental UK a few weeks ago. The camera and magazines is said to have been fully tested and cleaned by their technicians before they sent it. 

 

I'll surely try to get some junk film to test with. I tried to run the camera without the magazine door and it works. I can't see all of the take-up side since the mag is covered by the camera body and on board battery. But I get a decent view and would be able to see the take-up spool.

My lab is closed for holidays, but I'll ask for some double perf film when it's open again.

 

Could you clarify how I would do this: "If you can freez the take up sprockets with your fingers and turn the take up spindle you should feel some friction. There will be an allowable range for the torque. If you know your high school math you could measure this torque yourself."

Should I do it with the camera running? Where's the take up sprockets (sorry I'm a bit confused partly because of language difficulties…)? Dropped out of high school, so any math could be a problem :)

 

I think the film has been secured to the core, at least it felt like it when I unloaded the roll (and on the prior rolls I did before).

 

I'll pay more attention to the details next time I load and thread the mag and see what the results will be. On my first test I used one 400ft roll to test all magazines so I never tried a whole roll at once in one magazine yet.

 

Appreciate any more thoughts, and I'll report back after I've been able to test some more.

 


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#6 Kenny N Suleimanagich

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Posted 16 July 2015 - 02:51 PM

If your loop is correct, camera serviced, and your take-up is loaded properly, I’m baffled as to how this can happen. Have you tried it with any film stock besides the batch you’ve been using? 


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#7 Kalle Folke

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Posted 16 July 2015 - 03:10 PM

Yeah, feels strange it should happen. I've only tried with this expired Eterna 400T. My guess is that it's a combination of that being loose and me being new to loading the mags. I've got some fresh Kodak film in the fridge that I will try once I get something worth filming. Also the junk film test Gregg recommended.

I'm sure I'll find a way (very much hope so…), I got the camera partly because I get frustrated with loading the a-minima :)


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#8 Kenny N Suleimanagich

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Posted 16 July 2015 - 04:01 PM

It’s a great camera. A dream to load. I do find Fuji winds a little more loosely than Kodak. I have yet to run Orwo stock through the camera.

 

Unless you’re getting bad scratches, I wouldn’t worry about it and be vigilant while you’re running this older stock and loading/unloading. Be sure you have good tension in the loop throughout. 


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#9 Gregg MacPherson

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Posted 16 July 2015 - 07:30 PM

 

...I bought the kit from Arri rental UK a few weeks ago. The camera and magazines is said to have been fully tested and cleaned by their technicians before they sent it. 
 
....Could you clarify how I would do this: "If you can freez the take up sprockets with your fingers and turn the take up spindle you should feel some friction. There will be an allowable range for the torque. If you know your high school math you could measure this torque yourself."
Should I do it with the camera running? Where's the take up sprockets.....


Did all or your mags have exactly the same problem, or was it just one mag?

Load the mag like normal, leaving the take up door off. Mag is not fited to the camera. At the front of the take up side maybe you can see the lower drive sprocket. It has teeth that engage the film perforations. Hold that with your finger tip or thumb so it can't turn. Now turn the takeup spindle (turn the core) and you will fel how much friction.

You can also run the camera with the door off. Stop it now and again and you can check with your finger how tight the film feels on its way to the roll.

Gregg.
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#10 Gregg MacPherson

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Posted 17 July 2015 - 01:25 AM

 

Load the mag like normal, leaving the take up door off. Mag is not fited to the camera. At the front of the take up side maybe you can see the lower drive sprocket. It has teeth that engage the film perforations. Hold that with your finger tip or thumb so it can't turn. Now turn the takeup spindle (turn the core) and you will fel how much friction.


Sorry Kalle, I had liitle sleep last night and didn't have much time to write.
Holding the drive sprocket fixed while you turn the take up spindle (core) is done with no film loaded. Get it.
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#11 aapo lettinen

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Posted 17 July 2015 - 03:10 AM

I evened the roll again when putting it in the can. Maybe that will cause scratches on the film?

It may cause small scratches and also loosen small amount of remjet which then sticks to the emulsion side. has not been problem for me often but it is better to avoid this whenever possible


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