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16mm footage has vertical streaks (Aaton Ltr7)


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Hi All,

What would cause 16mm footage to look like this (smeared highlights/vertical streaks)? This was shot on an Aaton LTR7. Footage before and after are okay - the streaks go on for about 2 min and then footage is okay again.

film stills below:

 

 

Screenshot 2020-03-04 at 11.58.31[2].jpg

Screenshot 2020-03-04 at 11.58.58[2].jpg

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Looks like miss-timed shutter - e.g the shutter is open when the film is still being pulled down into position.

If the fault is intermittent (pun not intended) maybe a lubrication issue?

Edited by Phil Connolly
puntastic
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It is an out of sync shutter. Phil is spot on. A good test to check your shutter timing is to take a strip of film (3 feet or so) and with a fine tip marker, draw a straight line across the film from perf to perf. Do this for several frames. Lace up the camera with the marked film in the gate and looking through the lens port, inch the movement frame by frame. Here you can now see if the lines you drew are either not moving while the shutter is open while inching, telling you the shutter is in time OR the lines are moving while the shutter is open thus out of time and giving you the unintended visual effects! It’s completely fixable by a trained technician. Good luck!

G

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1 hour ago, Simon Wyss said:

Rather a lace-up mistake, film being pulled down during exposure, too tight loop(s)

No. There would be negative scratches and the image would jitter as opposed to streaking exposure. There could also be perf damage with a poorly laced camera movement. This is entirely different. 
 

G

Edited by Gregory Irwin
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5 hours ago, Gregory Irwin said:

It is an out of sync shutter. Phil is spot on. A good test to check your shutter timing is to take a strip of film (3 feet or so) and with a fine tip marker, draw a straight line across the film from perf to perf. Do this for several frames. Lace up the camera with the marked film in the gate and looking through the lens port, inch the movement frame by frame. Here you can now see if the lines you drew are either not moving while the shutter is open while inching, telling you the shutter is in time OR the lines are moving while the shutter is open thus out of time and giving you the unintended visual effects! It’s completely fixable by a trained technician. Good luck!

G

this is great. Thanks so much for the test instructions. And thanks to everyone else who responded.

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LTR shutters can't fall out of alignment with the pulldown very easily and it would be impossible for it to fall out of calibration and go back in again, as they're direct drive. The only other thing is a bad loop, but that of course would still give some sort of stability to the image at one point or another. With no stability at all, the pulldown isn't engaging at all. 

Generally this problem is met with an audibly louder camera and since it happened suddenly and then went away, it's probably just a worn/uncalibrated pulldown claw. These cameras have a tapered claw that doesn't protrude very much at all. Over time as the plastic cam roller wears down, the claw will protrude less and less until it can't catch the film consistently anymore. There are a few simple answers to solve this. One of course is to swap the cam roller, it's not a complex job for a tech to do, but it would require a tech to do it. Without a tool to measure how far the claw protrudes, it's hard to diagnose this over the internet, but most likely that's the problem with an old camera like that. Also it could be a bad pressure plate spring on the magazine. 

You also won't be able to test this by moving the movement slowly, it generally only happens when at full speed. 

 

 

Edited by Tyler Purcell
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I'm only guessing but I'd say a mistimed shutter rather than loop problem or worn claw. The blur lines are very clean, showing that the film advanced smoothly in an uninterrupted stroke while the shutter was open. Yet the problem comes and goes, so there's more to it. I don't know the mechanism of that camera but at a rough guess I'd say something is slipping in the mechanism that times the shutter with the pulldown claw.

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7 minutes ago, Jon O'Brien said:

I'm only guessing but I'd say a mistimed shutter rather than loop problem or worn claw. The blur lines are very clean, showing that the film advanced smoothly in an uninterrupted stroke while the shutter was open. Yet the problem comes and goes, so there's more to it. I don't know the mechanism of that camera but at a rough guess I'd say something is slipping in the mechanism that times the shutter with the pulldown claw.

I know the camera really well, it's all direct drive. It either works, or it doesn't work. 

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I'm much more familiar with Arris than Aatons, but what Tyler says about shutter sync going out and then coming back again is true - it's very unlikely. If the mirror coupling shifts somehow, it can't revert back by itself. A short loop I think would cause a different sort of effect, and would not correct itself after 2 minutes either. So I'm inclined to agree with Tyler that it's more likely to be a worn claw or an issue with the mag pressure plate. A technician familiar with Aatons needs to have a look at it I think.

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12 hours ago, May Isen said:

What would cause 16mm footage to look like this (smeared highlights/vertical streaks)? This was shot on an Aaton LTR7. Footage before and after are okay - the streaks go on for about 2 min and then footage is okay again.

There might be some more facts you can give that will help people diagnose it...Was the faulty 2 min section in the middle of a roll and the mag was never removed, but the camera was run/stop/run....? If so what stop/start points are there for the faulty 2mins..?

If the mag was removed at some point(s), note when they were, especially either end of the faulty 2mins. Were the loops reset before the mag was remounted to the camera?

Examine the film over the faulty 2mins, looking for tiny dents where the claw tip might have hit or scratched the film between perfs. Also look for scratching if the loops were lost completely and the film was being dragged through the gate by the drive sprocket.

I see the alert at the bottom of screen that Dom is replying, but I'll send this anyway.

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Oh, okay. So it's direct drive and pretty much impossible for shutter sync to go out and then come back again. In that case, as mentioned, it could be a combination of worn claw, with too much pressure from plate (or rather just the whole system a bit worn/out of adjustment), the loop starting to get lost a bit, then the film 'jumps' ahead past the gate as it releases. Off to a technician I'd say 🙂

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33 minutes ago, Gregg MacPherson said:

Examine the film over the faulty 2mins, looking for tiny dents where the claw tip might have hit or scratched the film between perfs. Also look for scratching if the loops were lost completely and the film was being dragged through the gate by the drive sprocket.

The camera would be very loud if that happened, it would be very evident to the operator as it would go from smooth quiet running to stupid loud running. Generally if the noise of the camera doesn't change much, it's the pulldown not engaging either via the claw not sticking out enough OR the pressure plate not pushing the film enough. 

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Actually, looking at the second image carefully, you can see it was briefly stationary, and then seems to have advanced while the shutter was still open. That would seem to suggest the film suddenly slipped. But there endeth my speculation.

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8 minutes ago, Tyler Purcell said:

The camera would be very loud if that happened, it would be very evident to the operator as it would go from smooth quiet running to stupid loud running. Generally if the noise of the camera doesn't change much, it's the pulldown not engaging either via the claw not sticking out enough OR the pressure plate not pushing the film enough. 

Sofar I thought your guesses were quite close to it. I think the OP should offer more info, and examining the neg should be an obligatory first or second step. Re the noise, if the claw is not engaged, not shifting film,  then the film will be pulled through the gate by the drive sprocket. Noisy..Y/N? Like Jon O. I wonder what allows the partial image of the woman's head, bentwood chair, table edge.

Is the claw sliding along the film and finally dropping into a perf, giving a moment of slack at the loops, positioning the film for that partial exposure. Or the opposite...

So much fun and speculation from so little information...

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For an up and coming music video I have, its for a  punk band shot on 16mm, this smearing effect is great for effect for intense scenes. Is there a way to do this on purpose and only when needed? I.e shooting an entire scene like this then re-calibrating the camera back safely.  

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14 hours ago, May Isen said:

Hi All,

What would cause 16mm footage to look like this (smeared highlights/vertical streaks)? This was shot on an Aaton LTR7. Footage before and after are okay - the streaks go on for about 2 min and then footage is okay again.

film stills below:

 

 

Screenshot 2020-03-04 at 11.58.31[2].jpg

Screenshot 2020-03-04 at 11.58.58[2].jpg

I`ve had this happen to me before with my LTR. 

Check you drive belt and make sure all the teeth are there. If your belt is old and worn out, this can be the problem that causes the image to look like that. 

If you find they are in good shape, then check the tension of the belt. There are two little wheels that can be adjusted to regulate the tension.

 Your drive belt could be bouncing around, messing with the take-up film not advancing while not engaging with the gears. 

I worked on a music video where they wanted to create a special effect with the image, so I loosen up the belts on the mags for a couple of shots to create that effect. But be careful because you can destroy the claw pin. 

 

IMG_7885.jpg

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33 minutes ago, Cale Boys said:

For an up and coming music video I have, its for a  punk band shot on 16mm, this smearing effect is great for effect for intense scenes. Is there a way to do this on purpose and only when needed? I.e shooting an entire scene like this then re-calibrating the camera back safely.  

If you have an SR3 it's possible to shift the belt timing of the mirror, but it's not something you would do on location, it requires partial camera disassembly.  

However, if the timing is only a little offset in a particular direction, it will smear when the shutter angle is at maximum, but then reducing the shutter angle can cover the part of the cycle where the film is being transported and the camera will behave normally (ie without smearing, but obviously with reduced shutter angle effects like choppier motion). That would be a way of turning the effect on and off.

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6 minutes ago, Dom Jaeger said:

If you have an SR3 it's possible to shift the belt timing of the mirror, but it's not something you would do on location, it requires partial camera disassembly.  

However, if the timing is only a little offset in a particular direction, it will smear when the shutter angle is at maximum, but then reducing the shutter angle can cover the part of the cycle where the film is being transported and the camera will behave normally (ie without smearing, but obviously with reduced shutter angle effects like choppier motion). That would be a way of turning the effect on and off.

Ah perfect, and yeah you're currently fixing my lens for my SR3 haha (My vintage cooke) Ill bring in my SR3 and get you to explain in person once its done 

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44 minutes ago, Felipe Larrondo said:

I`ve had this happen to me before with my LTR. 

Check you drive belt and make sure all the teeth are there. If your belt is old and worn out, this can be the problem that causes the image to look like that ....

 

IMG_7885.jpg

Ah ha! I'm not camera technician but a slipping drive belt was my first diagnosis. I don't mean to contradict anyone though. Just my thoughts of what occurred to me.

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11 minutes ago, Gregg MacPherson said:

Just thinking out loud here, is ramping possible with a cleverly designed external controller for an SR..?

Sent a message on that to Andrew at AZSpectrum. But what about forum member Aapo, who is fizzing right now about custom speed controllers for existing cameras. I'll ping him...

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3 hours ago, Jon O'Brien said:

Ah ha! I'm not camera technician but a slipping drive belt was my first diagnosis. I don't mean to contradict anyone though. Just my thoughts of what occurred to me.

If the belt in the magazine is bad, it can cause the sprockets to run unevenly. This can cause a loop to fail very fast, but again, it wouldn't magically go back to running normally. If the belt is bad, it would loose loops right away and you'd hear it. 

Edited by Tyler Purcell
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3 hours ago, Gregg MacPherson said:

Sent a message on that to Andrew at AZSpectrum. But what about forum member Aapo, who is fizzing right now about custom speed controllers for existing cameras. I'll ping him...

replied to the other thread. For SR1 and SR2 this should be relatively easy but I have understood the SR3 uses some kind of control protocol between the camera and the speed box like CCU1. Without knowing everything about this protocol it is difficult to say how much work there would be to develop this kind of accessory for the camera. I suspect it would be too time consuming and expensive to develop this kind of accessory unless the protocol is very simple (that is rarely the case) .

I sent a request to Arri if they want to share the details of the control protocol so that I could see if it could be done with reasonable time and resources

Edited by aapo lettinen
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Got a reply from Andrew at AZSpectrum. He does a speed ramping gizmo that works for for Arri/Aaton/Panavision.. I don't think he will mind if I paste his email and URLs..

Hello Gregg,

Thank you for your e-mail. 
Some time ago we designed the unit you are asking about. Currently all units are sold and we do not have them in stock. Information about this unit is on our website http://www.az-spectrum.com/sf.html

Best regards,
Andrew Zorawski

AZ Spectrum
53-53 62nd Street
Maspeth, NY 11378
USA

ph: 718-779-1892
www.az-spectrum.com
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