Aaton LTR Technical Guru Needed

[Anders Holmstrand]

A recent test of my LTR produced the following results:

 

The registration appeared steady but within the frame the image seemed to ride up and double expose just a bit - horizontally. This problem appeared intermittently. It was suggested that the shutter and pulldown claw might be out of sync. The possibility of a loop error did not seem likely. The camera seemed to perform very well otherwise and came to me in beautiful cosmetic condition. When this problem was not occuring, the images were sharp and the exposure was very accurate, even with the auto exposure meter.

 

Before I send this camera somewhere and incur repair costs, might anyone have an idea as to what might be going wrong? Can the problem be diagnosed by looking at the film?

 

If not, can anyone please recommend a highly qualified, honest and reasonably priced service facility for this camera.

 

Any other suggestions or thoughts will be appreciated as well.

 

Thanks all -

 

Anders

[Mitch Gross]

You say that a lost loop is unlikely, which is generally true on the LTR, but this sure sounds like a bad loop problem. Short of this it could be a mistimed shutter, meaning that the camera is advancing the film while the shutter is still open and exposing the image. If the loop is the wrong size then it's usually very easy to hear the problem as the camera would run quite loud. The camera should be able to handle a loop size anywhere from 13 - 16 frames, with some cameras running a bit quieter on shorter or longer lengths (mine likes 13 frames). To check for a mistimed shutter, load some test film into a mag and mount it to the camera without a lens on. Use the inching knob to clear the mirror shutter so that you can see a frame of film in the gate. Take a fine line Sharpie and mark out the edges of the frame. Now slowly advance the inching knob and watch the film frame to see if it moves at all before the mirror completely covers it from view. If it does move then you need to have the shutter's timing adjusted. If not than it was likely a loop issue with the mag.

 

I have to tell you that the odds are very low that it is a timing problem. It is almost certainly a loading issue. Be sure that when you load the mag to give a proper loop length. When mounting the mag to the camera make sure that the loop is fairly evenly spread between the top and bottom. If the camera runs a bit loud, try favoring the loop slightly to the top, as the film is [ulled down and when initially mounted it has to find proper alignment with the pulldown claw and the sprocket hole so a little extra up top couldn't hurt. Try different sized loops as well. You can do all of this yourself to see if the problem persists before sending the camera in for repair. If you are uncertain then Abel Cine Tech in New York and LA does excellent work and is the American distributor for Aaton. But if you have a local camera house in your area that is familiar with Aatons then this should not be the biggest of issues to check.

[Anders Holmstrand]

Thanks Mitch -

 

I spoke with a tech house and they suspected just what you've indicated here, so perhaps the first diagnosis I got was wrong - which may be my good fortune. I will run the tests that you've suggested. Much appreciated.

 

 

 

You say that a lost loop is unlikely, which is generally true on the LTR, but this sure sounds like a bad loop problem.  Short of this it could be a mistimed shutter, meaning that the camera is advancing the film while the shutter is still open and exposing the image.  If the loop is the wrong size then it's usually very easy to hear the problem as the camera would run quite loud.  The camera should be able to handle a loop size anywhere from 13 - 16 frames, with some cameras running a bit quieter on shorter or longer lengths (mine likes 13 frames).  To check for a mistimed shutter, load some test film into a mag and mount it to the camera without a lens on.  Use the inching knob to clear the mirror shutter so that you can see a frame of film in the gate.  Take a fine line Sharpie and mark out the edges of the frame.  Now slowly advance the inching knob and watch the film frame to see if it moves at all before the mirror completely covers it from view.  If it does move then you need to have the shutter's timing adjusted.  If not than it was likely a loop issue with the mag.

 

I have to tell you that the odds are very low that it is a timing problem.  It is almost certainly a loading issue.  Be sure that when you load the mag to give a proper loop length.  When mounting the mag to the camera make sure that the loop is fairly evenly spread between the top and bottom.  If the camera runs a bit loud, try favoring the loop slightly to the top, as the film is [ulled down and when initially mounted it has to find proper alignment with the pulldown claw and the sprocket hole so a little extra up top couldn't hurt.  Try different sized loops as well.  You can do all of this yourself to see if the problem persists before sending the camera in for repair.  If you are uncertain then Abel Cine Tech in New York and LA does excellent work and is the American distributor for Aaton.  But if you have a local camera house in your area that is familiar with Aatons then this should not be the biggest of issues to check.

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