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Phasing?


Travis Shannon

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The ACL has no phase function built into the body, for those of us with variable speed motors, when putting on a new mag is it good practice to run it at 2fps (or whatever the lowest option is) for a second or two to let the film catch at lower tension or is it overly cautious? If not, why? 

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After fitting a mag the claw is engaged with the inching knob.  Its good to be conscious of where the claw is and where the perfs are positioned so you know where it will engage. Allowing  the claw to engage in a random position can change the loops.

Running the camera before the claw has engaged  doesn't feel or sound good. Can't see a reason for doing it.

Gregg.

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  • 1 month later...

Hi Travis,

As far as starting an ACL with a new mag (or a mag that was taken off), there is no reason to worry about the speed on the motor.  If the perf on the new mag is not caught by the claw on its first rotation, it will be on the second, no matter the speed (so long as your camera's claw is set up properly).  And film is designed to take the impact of the claw.

As Gregg mention, you can inch the motor manually to catch that perf, but it's not nevessary either, and will not help with the loop inching by hand or running the motor will in both cases possibly miss the perf the first time around.  Because of this, I usually tell people to make the top loop a tiny bit longer (1 frame, if you have to count), rather than a bit shorter.

Remember that these cameras (and most film cameras of the News-gathering-on-film generation) were designed for ease of use by cameramen who only cared so much about their TV station's equipment.  They were expected to catch events on the go, not bother with minute details about loading procedures.  The Eclair 5-second magazine change was not just a marketing plot !

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6 minutes ago, Boris Belay said:

As far as starting an ACL with a new mag (or a mag that was taken off), there is no reason to worry about the speed on the motor.  If the perf on the new mag is not caught by the claw on its first rotation, it will be on the second, no matter the speed (so long as your camera's claw is set up properly).  And film is designed to take the impact of the claw.

it matters when determining if the loops are correctly set or if there is other mag related issue. so running just some seconds at low speed is generally done on any camera to hear that it is working correctly and good to go for normal speeds

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BTW, I'm not sure what you mean in this particular context  by 'phasing' or 'phase function', which has to do with syncronising two cycles together.  But in case somebody visits this thread hoping to find out something about phasing on the ACL, it is indeed a function that was built into the electronics of the ACL II (and only the ACL II).

The Lemo connector (6-pin hermaphrodite) in the bottom base of the ACL II (and absent from earlier tall base ACLs) is desighed to receive an external synch signal that controls the last series of ACL motors (code MIPIL, with silver and black locking speed button) when it is on the 'E' speed setting (for External).

Eclair made a very rare accessory box to plug into this connector and receive an external signal.  This BOTEX accessory has a phase correction function to precisely adjust the shutter phase to the external signal.  This was mostly used at the time when filming a CRT (TV, etc.), as the phase adjustement could move the black bar out of the image (with the main speed being synchronised by a feed from the TV.

Here are some images of the rare beast :

IMG_2174 copy.JPG

IMG_2183 copy.JPG

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10 minutes ago, aapo lettinen said:

it matters when determining if the loops are correctly set or if there is other mag related issue. so running just some seconds at low speed is generally done on any camera to hear that it is working correctly and good to go for normal speeds

Yes Aapo, if you don't know the camera, or if you are servicing it.  But once you know that your camera is functional, and you have loaded your mags properly, you can just pop in a mag and run the motor at any speed.  

I never bother switching the motor to low speed for a new mag, especially if I'm worried about film noise, since only my actual shooting speed will let me know about the noise level for that shot.  But I do always, of course, run the camera a couple of seconds to check the loop noise.

Now, anybody can be as careful as they want, obviously, but from a long and extensive experience with ACLs and other film cameras, all I am saying is that it's not a necessity.  And if you're going to miss that shot that's happening there and then, it would be a shame ! ?

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Hi Boris, thanks for replying- yes this practice is basically how I load mine nowadays including leaving a bit more in the top loop , for reference I’m using the term phase as it is used on arri cameras as the one button function for mounting a new mag and then auto engaging claw in inching speed. Cool to see the botex, never knew there was a sync adjuster for the ACL. 

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  • 1 year later...
On 2/5/2023 at 7:16 PM, Boris Belay said:

BTW, I'm not sure what you mean in this particular context  by 'phasing' or 'phase function', which has to do with syncronising two cycles together.  But in case somebody visits this thread hoping to find out something about phasing on the ACL, it is indeed a function that was built into the electronics of the ACL II (and only the ACL II).

Its called Phase Shifting.

I was used to use that feature extensively in my works. Arriflex 16BL with BLEQ motor and 16SR/SRII need an external accessory (PHU) for controlling. SR3 doesn't need, however you can use the external synchronization unit ESU-1.

As you mentioned, the BOTEX unit was intended for the ACL II.

 

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