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Flicker problem with S16 ACL2


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#1 Benjamin Coppens

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Posted 13 May 2008 - 03:22 PM

Hello!

I'm having flicker problems in image with my super16 ACL2...I've noticed that the mirror is not completely sync with the shutter...Could that be the problem?

Thank you very much!

Benjamin.
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#2 Saul Rodgar

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Posted 13 May 2008 - 06:19 PM

Did you take off the motor? That can cause the flicker problem if you didn't mark for the motor gear to align with the camera gear (where the shutter is closed) so that they keep sync when the camera runs. It could be something else entirely, like power, an internal short, etc?

Better call Bernie O'Doherty or George Zorzoli, google them up, they are the b

Edited by Saul Rodgar, 13 May 2008 - 06:22 PM.

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#3 Olex Kalynychenko

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Posted 14 May 2008 - 02:45 AM

Hello!

I'm having flicker problems in image with my super16 ACL2...I've noticed that the mirror is not completely sync with the shutter...Could that be the problem?

Thank you very much!

Benjamin.


You have footage with pulsation of density on nearby pictures ?
What type of lighters you use ?
What frequency have AC main power&
Your camera have crystal sync speed, multi speed motor ?
What speed you set on camera.

The flicker problme can be at beat between freqency of light pulses and camera speed.


Or , you have darkness part on image ? or the part of frame - smeared picture


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#4 Benjamin Coppens

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Posted 14 May 2008 - 06:29 AM

Hello,

I've shooted outside with 50D at 25fps...no HMI or other lights were used, only available light.
The motor is the heavy duty motor.
I have flicker in the highlights...The mirror covers the gate for about a half...1 image of 2...it is not sync.
I think that could be the problem.

Regards,
Benjamin.
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#5 Benjamin Coppens

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Posted 16 May 2008 - 01:33 PM

The flicker take place on the right side of the image were the gate was trimmed to super16mm...It is also the place were the mirror is covering the film a litlle while running. Someone synced it a little beter so the flicker is less present but it is still there!
Does someone know if the mirror has to be trimmed a little for super16 conversion or not?
Can the camera be synced with the original 16mm mirror?
How can we achieve that?
We were not able to do it.


Thank you,
Benjamin.
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#6 timHealy

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Posted 17 May 2008 - 09:20 AM

I seem to recall hearing in the past that someone here had a flicker problem that may have been associated with a damaged mirror. Have you searched the archives? I think there may have been a chip that had kicked light back at one point in the mirror movement.

Does that sound familiar to anyone?

Best

Tim
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#7 jacob thomas

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Posted 20 May 2008 - 02:46 AM

The flicker take place on the right side of the image were the gate was trimmed to super16mm...It is also the place were the mirror is covering the film a litlle while running. Someone synced it a little beter so the flicker is less present but it is still there!
Does someone know if the mirror has to be trimmed a little for super16 conversion or not?
Can the camera be synced with the original 16mm mirror?
How can we achieve that?
We were not able to do it.


Thank you,
Benjamin.


IIRC all eclair acl conversions require a new mirror shutter with smaller shutter angle (144º) to cover the extra s16 area. If your mirror shutter was not replaced during the conversion this is probably the problem.
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#8 Kristian Schumacher

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Posted 20 May 2008 - 04:25 AM

IIRC all eclair acl conversions require a new mirror shutter with smaller shutter angle (144º) to cover the extra s16 area. If your mirror shutter was not replaced during the conversion this is probably the problem.


The ACL does not use a mirror shutter. It has a focal plane shutter and an oscillating mirror for reflex viewing. The smaller shutter angle needed for s16 is to allow time for the mirror to clear before/after the shutter opens.

Kristian
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#9 Saul Rodgar

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Posted 20 May 2008 - 08:08 AM

The ACL does not use a mirror shutter. It has a focal plane shutter and an oscillating mirror for reflex viewing. The smaller shutter angle needed for s16 is to allow time for the mirror to clear before/after the shutter opens.

Kristian



Correct. You still need to modify the original non-mirror shutter to 144 degrees. There is a kit that can be purchased here:

http://members.aol.c...16ACL/techs.htm

Modifying an ACL to S16 without modifying the shutter is not going to work, as you have found out.

You may want to send it to one of the techs listed on that page, for doing a pro job is best left to the pros.

Edited by Saul Rodgar, 20 May 2008 - 08:10 AM.

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#10 Benjamin Coppens

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Posted 20 May 2008 - 09:55 AM

Hello,

Yes indeed, that was the problem...I've cemented a piece of aluminium (black) to the shutter myself to reduce it's opening angle and the flicker has disappeared!
The ACL is so cool to work with...the mechanism is so simple and logic!

Best regards everybody,
Benjamin.
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