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Aaton XTR frame rates


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#1 Vincent De Paula

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Posted 14 September 2006 - 03:10 PM

Hi guys,
I've been making some tests on an Aaton XTR for un upcoming shoot on S16mm.
When running some speed tests, I noticed that the camera was capable of running up to 75fps without a mag on, or with an empty mag on.

When it came to run some film, on the same setting, the camera was only capable to run up tp 54fps.
I wonder if there is any logic to this.
The Mag is driven magnetically from an intermediate drive connected to the camera motor, a magnetic wheel on the inner side of the camera body couples with a similar wheel on the throat of the mag to transport the film. Would the issue be there?

Thank you kindly for your answers.

Best Regards
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#2 Nathan Milford

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Posted 14 September 2006 - 03:54 PM

Are you using the camera's on-board speed dial or an external speed control. The older cameras are dumb enough to go whatever speed you punch in. But, you risk destroying your claw or bearings.

Could you identify the model of XTR you have and your testing methodology. Also your description is a bit difficult to understand.

A plain jane XTR will only go up to 54fps, and it needs 16v to do that. Those still have the old square rod hole in the front. An XTRplus will typically have the screw-in 15mm rods in front and comes in two flavors. A Bi-Phase XTRplus will go up to 60fps and needs 16v to do so. A Tri-Phase XTRplus will go up to 75fps and can do so on 12v. You know your XTRplus is Tri-Phase if it says 'Tri' on the motor gasket/cover, otherwise it will say something like 'P23-X'. An XTRprod will go up to 75fps (on 12v) but most of them have a built in protection that makes them only go up to 36fps then you have to manually go up to 75fps from there.

You cannot mix and match Bi-Phase and Tri-Phase electronics to make an older camera go faster.
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#3 Vincent De Paula

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Posted 14 September 2006 - 05:10 PM

Are you using the camera's on-board speed dial or an external speed control. The older cameras are dumb enough to go whatever speed you punch in. But, you risk destroying your claw or bearings.

Could you identify the model of XTR you have and your testing methodology. Also your description is a bit difficult to understand.

A plain jane XTR will only go up to 54fps, and it needs 16v to do that. Those still have the old square rod hole in the front. An XTRplus will typically have the screw-in 15mm rods in front and comes in two flavors. A Bi-Phase XTRplus will go up to 60fps and needs 16v to do so. A Tri-Phase XTRplus will go up to 75fps and can do so on 12v. You know your XTRplus is Tri-Phase if it says 'Tri' on the motor gasket/cover, otherwise it will say something like 'P23-X'. An XTRprod will go up to 75fps (on 12v) but most of them have a built in protection that makes them only go up to 36fps then you have to manually go up to 75fps from there.

You cannot mix and match Bi-Phase and Tri-Phase electronics to make an older camera go faster.


Hey Nathan,

I'm using the camera's on-board speed dial.
I'm pretty sure this is the XTR Plus, and it states P23-X on the motor cover.
There is not setting for 60fps though, and like I previously said, it can go all the way to 75fps (as it says in display) withough a magazine on. If left in the same spped on the speed dial but with a loaded magazine it will go down to 54 fps.

I was running these tests at 12V.

Thank you again
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#4 Nathan Milford

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Posted 14 September 2006 - 11:34 PM

Hey Nathan,

I'm using the camera's on-board speed dial.
I'm pretty sure this is the XTR Plus, and it states P23-X on the motor cover.
There is not setting for 60fps though, and like I previously said, it can go all the way to 75fps (as it says in display) withough a magazine on. If left in the same spped on the speed dial but with a loaded magazine it will go down to 54 fps.

I was running these tests at 12V.

Thank you again


Okie doke. It might be a Bi-Phase XTRplus.. there could be a few that fell through the cracks as XTRpluses and were only rated at going 54fps. It is Aaton afterall...

First thing's first. I'd get an external speed checker to confirm that it is 75fps. Also, 75fps sounds VERY different from 54fps. As different 54fps sounds from 24fps. You may have an issue with your crystal or tach or even your side display. If you live by occam's razor, this is your problem. The long and short is that if there isn't a dial setting for 75fps... your camera shouldn't be able to go 75fps... so if it is indeed jumping up to 75fps... you have a serious problem. If the tach just thinks it's going up there... you have a mild problem.

Probing deeper, however, on newer cameras there are two spring loaded 'bullets' that engage the mirror shaft to add opposing friction to keep the mirror from spinning wildly... thus making the tach do odd things.. confusing it. Ther addition of a load on the claw (loaded mag) could be putting enough load on the mechanism proper to act as the bullets would nominally.

Also, if it's not a tri-phase camera (and it doesn't sound like it is)... you should have to put 16 volts through it to get it up to 54fps with a load of film, otherwise you'll hear the motor falter and the speed fluctuate as it tries to get above 40fps or so.

Either way, I'd send it in for an evaluation. Lemac should be able to help you out.
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#5 Vincent De Paula

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Posted 15 September 2006 - 09:43 AM

Okie doke. It might be a Bi-Phase XTRplus.. there could be a few that fell through the cracks as XTRpluses and were only rated at going 54fps. It is Aaton afterall...

First thing's first. I'd get an external speed checker to confirm that it is 75fps. Also, 75fps sounds VERY different from 54fps. As different 54fps sounds from 24fps. You may have an issue with your crystal or tach or even your side display. If you live by occam's razor, this is your problem. The long and short is that if there isn't a dial setting for 75fps... your camera shouldn't be able to go 75fps... so if it is indeed jumping up to 75fps... you have a serious problem. If the tach just thinks it's going up there... you have a mild problem.

Probing deeper, however, on newer cameras there are two spring loaded 'bullets' that engage the mirror shaft to add opposing friction to keep the mirror from spinning wildly... thus making the tach do odd things.. confusing it. Ther addition of a load on the claw (loaded mag) could be putting enough load on the mechanism proper to act as the bullets would nominally.

Also, if it's not a tri-phase camera (and it doesn't sound like it is)... you should have to put 16 volts through it to get it up to 54fps with a load of film, otherwise you'll hear the motor falter and the speed fluctuate as it tries to get above 40fps or so.

Either way, I'd send it in for an evaluation. Lemac should be able to help you out.



Thank you so much for your help Nathan.
I envy your knowledge!

Regards
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#6 Nathan Milford

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Posted 15 September 2006 - 09:58 AM

Woops. I wrote Lemac, I mean ICE Film in the UK.

- nathan
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CineLab

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FJS International, LLC

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Technodolly

The Slider

Ritter Battery

Visual Products

Rig Wheels Passport

Glidecam

Wooden Camera

Aerial Filmworks

Media Blackout - Custom Cables and AKS

Broadcast Solutions Inc

rebotnix Technologies

Gamma Ray Digital Inc

Opal

Paralinx LLC

Abel Cine

Metropolis Post