RE: Eclair Cameras: shooting 24fps - flicker on test roll

[Bernie ODoherty <bernie_odoherty@emerson.edu>]

-----Original Message-----
From:	MARK HOWARD [mailto:mark@howard3596.fsnet.co.uk]
Sent:	Fri 12/12/2003 11:40 AM
To:	EclairACL@topica.com
Cc:	
Subject:	Re: Eclair Cameras: shooting 24fps - flicker on test roll

Thanks bernie for the info
if the motor was performing badly would you expect the orange out of sync
light to illuminate,
it flicks on at the begining of the shot for a split second then turns off ,
or is the camera losing
sync speed totally different issue, i have just swopped crystals for a 25fps
and the light does the same
comes on for a split second then off again, everything else looks tight with
no play , i think i will have
to run another test with and without the redheads, any other info greatly
appreciated.
Mark Howard
----- Original Message -----
From: Bernie ODoherty <bernie_odoherty@emerson.edu>
To: <EclairACL@topica.com>
Sent: Friday, December 12, 2003 4:01 PM
Subject: RE: Eclair Cameras: shooting 24fps - flicker on test roll


>
>
>
> -----Original Message-----
> From: MARK HOWARD [mailto:mark@howard3596.fsnet.co.uk]
> Sent: Fri 12/12/2003 6:34 AM
> To: EclairACL@topica.com
> Cc:
> Subject: Eclair Cameras: shooting 24fps - flicker on test roll
>
> Hi to everyone again and thankyou Ian ,i had already sent
> a test roll for telecine when i posted the flicker and redhead light
> question,the beta tape is back and there is a very noticable flicker
> from start to finish, the shutter has not been modified to the 144
> degree angle and if viewed through the gate there is one pass of the
> shutter that has no mirror visible the the next two shutter passes
> show the mirror just creeping into shot on the S16 enlarged side of the
> gate, its not a lot,would this cause a flicker across the entire
> frame, I have checked that it is right across the frame by using black
> card to cover variuos parts of the screen, also the telecine house
> transfered it 4:3 and not S16 so I am guessing that the part of the
> frame that is missing from the telecine would be the S16 enlarged
> side of the gate were you would expect the flicker to be isolated.
> The test was shot using 800 watt redheads plugged into a domestic supply
> at my house which has wireing and old power boxes under the
> stairs and dating from the 60's or am i clutching at straws.
> I have spoken to les Bosher who as usual is very knowledgable and
> helpfull ,but before sending it off just wondered if any one else using
> the standard shutter of 180 degrees with an S16 acl has seen any
> similar flicker.
>
>
>
>
>
>
> Hi Mark,
>
> Bernie O'Doherty here....I worked with Les at Sammy's.
> I don't think that flicker would be caused by the mirror creeping into the
shot.
> If anything, that would help, by blocking the light.
> Perhaps it is a malfunction in either the motor, or the movement being too
slack.
> If the motor is not running well, speedwise, and slightly varying in
speed, this can be transmitted to a slack movement, and thus amplified. The
end result will be a variation in the EXPOSURE. So, for example, one frame
will be a twentyfourth of a second. The next, a 23.9 of a second, the next a
24.01 of a second and so on.....end result being image flicker.
> Hope this helps,
>
> Cheers,
>
> Bernie o'
>
>
>





I think you're ok re the light....that's normal.
Even if it were not running at speed, it would tend to stay pretty close.
You could check speed by looking through your camera, running, without lens and mag, at another camera running, without lens and mag.
Have something white to look at.
Run both cameras while looking through the aperture plate.
You should see either a darkness, or a lightness.
You should not see a CHANGE FROM DARKNESS TO LIGHTNESS while running.
This would indicate a problem with either, or both cameras, crystal speed.
Try to feel the shutter looseness by gently putting a q-tip cotton stick to it and moving it up and down with the shutter, camera stopped.
You should have little or no shitter-anglular movement.
If you do, this could be the problem, especially if your movement timing is slightly off.

Keep me informed,

Cheers,

Bernie O'

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