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Pulldown claw is causing flicker


Allyn Iwatsuru
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So I’ve been having a tiny flicker issue in the top left corner of my image on my acl and I think ive deduced it to light reflecting off of the pulldown claw when it recedes. Does anybody have any bright ideas on fixing this issue?

Edited by Allyn Iwatsuru
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The claw should not be an issue once retracted the moment the shutter opens. This sounds like a possible out of sync shutter to me. That’s really easy to determine by a simple test.
 

Take about 3 feet of negative that you don’t mind wasting. On the emulsion side, with a fine tip sharpie, draw a straight line across the film from the perforation (s). Do this for several frames. Thread up the film in the camera. Looking through the open lens port, manually inch the movement so you can see the shutter opening. Now you can see the drawn sharpie line facing you. If you see the line perfectly static will inching the movement ( rock it back and forth if possible), the film is still for the moment of exposure. Your shutter is in sync. If you see the line slightly moving, your shutter is out of sync and opening while the film is transporting from one frame to the next. That could be what you are seeing. 
 

Below are 2 photos of how you can do this. Here, the entire gate was traced. A simple line drawn as described above will work as well. Let us know what you find!

G

 

B1DA7048-6E3F-443E-BFE9-D30790C894C2.jpeg

08ED7877-5ADD-4002-B7F4-1932C3B4257E.jpeg

Edited by Gregory Irwin
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15 hours ago, Simon Wyss said:

Claw should be blackened or at least darkened. I know it’s steel, so not a small job. Try to shield the space in front of the aperture with a piece of black felt or paper.

I’ll give it a shot, do think using a fine tip marker on the claw could have any serious negative effects? I can’t imagine it would since it’s only coming in contact with the perfs.

9 hours ago, Gregory Irwin said:

The claw should not be an issue once retracted the moment the shutter opens. This sounds like a possible out of sync shutter to me. That’s really easy to determine by a simple test.
 

Take about 3 feet of negative that you don’t mind wasting. On the emulsion side, with a fine tip sharpie, draw a straight line across the film from the perforation (s). Do this for several frames. Thread up the film in the camera. Looking through the open lens port, manually inch the movement so you can see the shutter opening. Now you can see the drawn sharpie line facing you. If you see the line perfectly static will inching the movement ( rock it back and forth if possible), the film is still for the moment of exposure. Your shutter is in sync. If you see the line slightly moving, your shutter is out of sync and opening while the film is transporting from one frame to the next. That could be what you are seeing. 
 

Below are 2 photos of how you can do this. Here, the entire gate was traced. A simple line drawn as described above will work as well. Let us know what you find!

G

 

B1DA7048-6E3F-443E-BFE9-D30790C894C2.jpeg

08ED7877-5ADD-4002-B7F4-1932C3B4257E.jpeg

I’ve done this and it’s not a sync issue, thank you though. I can’t seem to embed photos from Flickr but I took a picture and you can clearly see light reflecting off the claw which would also mean it’s coming through the gap the claw moves through. This seems to make sense since it’s every other frame and the mirror covers it every other frame.

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1 hour ago, Allyn Iwatsuru said:

Do you think using a fine tip marker on the claw could have any serious negative effects?

No, but you have to make sure the ink stays on by degreasing the metal.

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Hi Allyn, could you post some footage? Also, have you checked with a flashlight in a dark room there aren't any holes in your camera front. After my ACL conversion there was a tiny hole in the side of the outer TS-mount. Issues showed up when I used c-mount. I tried to find the cause for a long time and there it was, in front of my eyes (quite literally!) all the time... quick fix: gaffer's tape.

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On 2/7/2022 at 9:41 PM, Simon Wyss said:

No, but you have to make sure the ink stays on by degreasing the metal.

good point, thank you.

On 2/8/2022 at 12:47 AM, Heikki Repo said:

Hi Allyn, could you post some footage? Also, have you checked with a flashlight in a dark room there aren't any holes in your camera front. After my ACL conversion there was a tiny hole in the side of the outer TS-mount. Issues showed up when I used c-mount. I tried to find the cause for a long time and there it was, in front of my eyes (quite literally!) all the time... quick fix: gaffer's tape.

I've seen the discussion on the flicker issue you've mention and there are no holes on the front and my camera is regular 16. I've tested two different mags 1x400ft and 1x200ft, two different film stocks, two different scans from two different companies and it doesn't matter which lens mount I use TS or C.

https://youtu.be/n1sLF6PW-u0

Edited by Allyn Iwatsuru
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Have you checked your viewfinder for a possible light path to "kick back" through to the aperture?

I haven't personally shot with an ACL, but have had mysterious flicker issues with other cameras that were traced back to a reflex viewfinder eye cup not sealing against my face correctly.

Is your eye cup in good shape?  Does it fit your face properly?

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On 2/10/2022 at 4:20 AM, Frank Wylie said:

Have you checked your viewfinder for a possible light path to "kick back" through to the aperture?

I haven't personally shot with an ACL, but have had mysterious flicker issues with other cameras that were traced back to a reflex viewfinder eye cup not sealing against my face correctly.

Is your eye cup in good shape?  Does it fit your face properly?

This I have not ruled that out, but didn’t think it was the issue because it’s so constant. Maybe there’s an issue with my viewfinder. I can’t close the shutter all the maybe I’ll just remove it and cover the port.

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