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focal plane shutter-eclair ACL


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#1 Erkan Umut

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Posted 23 March 2007 - 06:01 PM

This is a quote from eclair ACL manual:

Contrary to reflex cameras in which the mirror mounted at 45' acts as a shutter, the ACL has a plane shutter of large diameter completely independant of the mirror (14). It is placed very close to the film plane with an opening of 175'. Cutting the image in the direction of the smallest dimension gives a perfect exposure, maximum definition and reduction of jerky effect on some panning shots.

What does it mean "cutting the image in the direction of the smallest dimension"? Does it mean the shutter is placed very close to the aperture, or?
Why do mirror shutters (placed at 45') cause the jerky effects while quick panning?

Similar system applies to Panaflex cameras as far as I know. Does someone have the system diagram and info about the shutter and mirror of Panaflex cameras?

Thank you for all... :)
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#2 salt-sg

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Posted 24 March 2007 - 09:46 PM

I think that it is similar to the difference between the center-shutter and focal-plane shutter of the still cameras.
(Thought it's not the same at all.)

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#3 Erkan Umut

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Posted 25 March 2007 - 08:46 AM

I think that it is similar to the difference between the center-shutter and focal-plane shutter of the still cameras.
(Thought it's not the same at all.)

Thank you for your reply and the diagram. What is the source of your diagram? Any publication or your experience?
The light through the lens results a cone towards the aperture. The focal plane shutter is very close to the aperture, so it cuts the smallest part of this cone.
I've seen similar things in Russian cine technology books I have.
Any comments...
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#4 salt-sg

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Posted 25 March 2007 - 09:02 PM

When I considered the flicker-motion problem of 24P-DV camera before, I derived this diagram based on the knowledge of the center shutter.
(DV camera has not almost inclination.)
However, the diagram is exaggerated.
Because the inclination of the diagram is bit part of the entire diagram, the existence of the effect which the Manual of Eclair says is not certain.
Out of curiosity, I will observe the difference of image shot by ACL and ST after this.
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#5 Erkan Umut

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Posted 26 March 2007 - 04:12 AM

When I considered the flicker-motion problem of 24P-DV camera before, I derived this diagram based on the knowledge of the center shutter.
(DV camera has not almost inclination.)
However, the diagram is exaggerated.
Because the inclination of the diagram is bit part of the entire diagram, the existence of the effect which the Manual of Eclair says is not certain.
Out of curiosity, I will observe the difference of image shot by ACL and ST after this.

Thanks... I eagerly am waiting for your observation...
By the way, my hobby is motion-picture technology.
What is your field?
I've been in Japan in 1995 for one month, and have visited the projector makers Tokiwa Tokyo, Eiki Osaka and Elmo Nagoya, and was the Agent for Tokiwa in Turkey. Japan is one of the makers of high quality precision cine machinery...
Do you have have any manual and parts catalogue of the latest model eclair ACL?
Pls. visit my web at http://www.erkanumut.com/acl.htm

Edited by Erkan Umut, 26 March 2007 - 04:14 AM.

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