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16mm camera with a butterfly shutter


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#1 Brian Rose

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Posted 03 November 2006 - 05:07 PM

All,
Are there any 16mms out there that have a twin blade "butterfly" shutter? I'm looking for one I can modify with alternating color filters, like Kinemacolor. Thanks
Brian Rose
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#2 Luke Prendergast

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Posted 03 November 2006 - 05:11 PM

The K3 and older CP16s do.
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#3 David Sweetman

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Posted 03 November 2006 - 06:45 PM

As well as the arri 16bl and arri sr1.

of course each 'open' section exposes the same frame...
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#4 Nick Mulder

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Posted 04 November 2006 - 05:52 PM

As well as the arri 16bl and arri sr1.

of course each 'open' section exposes the same frame...


really ?

I'm a bolex nerd so dont know much about Arri's but what is the reason for exposing each frame twice ?

Talk of shutter angles would become redundant in terms of smoothness as you would always have a segment of motion missing in each frame...

I know that projectors will project and image twice thereby 24fps is actually 48 'flicks' - something to do with that maybe ?

Also wouldn't that make the pull down mechanics have to really heave the film down a lot faster than it really needs to ?


or are you refering to the kinemacolor process ?


cheers :)
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#5 Tim Carroll

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Posted 04 November 2006 - 06:29 PM

Okay, I am not sure what folks are referring to as butterfly shutters, but if you are really meaning bow-tie shutters, then the Arriflex 16SR does not qualify. The Arriflex 16S, 16S/B, 16St, and 16M all have bow-tie shutters. On the Arriflex, a bow-tie shutter doesn't expose the negative twice, it rotates at half the speed of the movement. The mirror does a complete revolution every two frames.

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#6 Jonathan Benny

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Posted 04 November 2006 - 08:43 PM

of course each 'open' section exposes the same frame...


The disk with two 90 degree openings is turning at half the speed of what a shutter with a 180 degree opening would, therefore the same shutterspeed. Each frame is only exposed once and the film is advanced between each 90 degree opening.

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#7 Sam Wells

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Posted 04 November 2006 - 08:54 PM

Talk of shutter angles would become redundant in terms of smoothness as you would always have a segment of motion missing in each frame...

I know that projectors will project and image twice thereby 24fps is actually 48 'flicks' - something to do with that maybe ?


Arri S and 16BL segment the mirror itself with a small stripe so you see your "48 flicks" so to speak in the viewfinder but this has no effect on how the film is exposed when the shutter is open.

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#8 Mark Dunn

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Posted 06 November 2006 - 11:56 AM

It's only projection which uses the double (or even triple, IIRC, for 8-mm) exposure. If you think about it, you'd get some odd double-exposure effects with a moving subject if cameras did it.
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#9 David Sweetman

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Posted 06 November 2006 - 02:03 PM

The disk with two 90 degree openings is turning at half the speed of what a shutter with a 180 degree opening would, therefore the same shutterspeed. Each frame is only exposed once and the film is advanced between each 90 degree opening.

AJB

crazy, so it's 180 equivalent. That makes sense. Sorry for putting out wrong information, I was always told that's how it went down. anyway I'm glad I said it or I never would have known the truth.

I am aware the srII and srIII have variable shutters, but I was fairly sure the srI had a butterfly shutter and was fixed at 180...
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