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#1 J Costantini

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Posted 20 May 2005 - 05:30 PM

Hi.
I would like to know more about 3-PERF.
Do you have any websites to recommend? Or can you post a simple explanation. I have an idea of what it is, but would like to hear more about what´s possible and what is not possible with 3 perf. What may change during the processes (photochemical and electronic).

Have you shot with 3-perf cameras?

I know there are cameras like these here (in Brazil) but very few information about the advantages and risks (if any).

Thanks.
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#2 David Mullen ASC

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Posted 20 May 2005 - 05:44 PM

The standard 35mm camera and projection formats are 4-perf (four perforations tall.) In Full Aperture (the largest area possible using the whole film) a 4-perf frame is 1.33 : 1 (4x3). This dates back to the silent era.

Since most modern filmmaking is widescreen, in many 4-perf 35mm formats, the whole 4-perf vertical area is wasted by cropping to widescreen. For example, the 1.85 projection format crops the 4-perf frame by more than 25%.

In fact, the only projection format currently used that needs the whole 4-perf area is anamorphic (CinemaScope).

Reducing the camera pulldown by one perf to only 3-perfs tall creates a full aperture negative that is about 1.78 : 1 (16x9). And it saves you 25% on film stock, with no quality loss if the end goal is cropping to 1.85 or 2.39 (compared to cropping 4-perf to 2.39, since a 2.39 frame only uses about 2 1/2 perfs out of four). And 3-perf is ideally suited for transfer to 16x9 video without any waste.

Downsides are also many since 3-perf is not as common as 4-perf and no theatrical projection is 3-perf (and very little lab projection), meaning that if a print is required, it has to be optically or digitally copied over to a 4-perf 35mm projection format (i.e. standard 1.85 or 2.39 anamorphic.)

Some links:

http://www.arri.com/.../nab/3-perf.htm
http://www.arri.com/...10/filmfest.htm
http://www.cinematog...GB/3_perf_2.htm
http://www.postprodu...-perf_35mm.html
http://psychcentral....psypsych/3-perf
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#3 J Costantini

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Posted 02 June 2005 - 07:10 AM

thanks once again, david
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#4 Nguyen D. Nguyen

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Posted 10 June 2005 - 05:33 PM

The standard 35mm camera and projection formats are 4-perf (four perforations tall.) In Full Aperture (the largest area possible using the whole film) a 4-perf frame is 1.33 : 1 (4x3).  This dates back to the silent era.

Since most modern filmmaking is widescreen, in many 4-perf 35mm formats, the whole 4-perf vertical area is wasted by cropping to widescreen. For example, the 1.85 projection format crops the 4-perf frame by more than 25%.

In fact, the only projection format currently used that needs the whole 4-perf area is anamorphic (CinemaScope).

Reducing the camera pulldown by one perf to only 3-perfs tall creates a full aperture negative that is about 1.78 : 1 (16x9). And it saves you 25% on film stock, with no quality loss if the end goal is cropping to 1.85 or 2.39 (compared to cropping 4-perf to 2.39, since a 2.39 frame only uses about 2 1/2 perfs out of four). And 3-perf is ideally suited for transfer to 16x9 video without any waste.

Downsides are also many since 3-perf is not as common as 4-perf and no theatrical projection is 3-perf (and very little lab projection), meaning that if a print is required, it has to be optically or digitally copied over to a 4-perf 35mm projection format (i.e. standard 1.85 or 2.39 anamorphic.)

Some links:

http://www.arri.com/.../nab/3-perf.htm
http://www.arri.com/...10/filmfest.htm
http://www.cinematog...GB/3_perf_2.htm
http://www.postprodu...-perf_35mm.html
http://psychcentral....psypsych/3-perf

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David, I just had a quick question.

With 3-perf, I heard there was a problem with editing it on a flat bed since it doesn't calculate into the "number of frames per foot" value so well as the 4 perf 16 frames per foot. Is there some standard way around this?
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#5 Dominic Case

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Posted 10 June 2005 - 08:13 PM

With 3-perf, I heard there was a problem with editing it on a flat bed since it doesn't calculate into the "number of frames per foot" value so well as the 4 perf 16 frames per foot. Is there some standard way around this?

Not really. None of the manufacturers of flatebed editors have expressed any interest in making a 3-perf mod. You can change the sprockets on a projector to run 3 perfs at a time instead of 4, but it's not so simple with a flatbed as they use a multifacted prism which is the right size for 4-perf.

If there was no such thing as non-linear editing then someone would have made a modification by now - but really 3-perf has gained a new life BECAUSE you can get the images off the film into a computer for editing, leaving the non-standard perforation count behind.

3-perf is good for TV finish work, and good if you are going through a DI, but the problems of editing 3-perf workprint, and the problems of neg-matching (because of the fact that keykodes occur every foot, or 21 1/3 frames instead of a round number, make it unattractive for a traditional finish.
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#6 Phil Rhodes

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Posted 11 June 2005 - 07:48 AM

Hi,

To be honest with you, it's enough fun for DI...

Phil
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Media Blackout - Custom Cables and AKS

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Aerial Filmworks

Technodolly

Visual Products