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Strobe effect on film


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#1 john torres

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Posted 20 May 2008 - 09:54 PM

Hello,

I?m shooting a feature and I?m interested in using a strobe effect similar to the one that you get by shooting at frame rates such as 16 or 12 fps. This effect has been used by Robert Richardson in much of his work, particularly JFK and Januz Kaminski in Private Ryan.
I know this is usually done by optically re-printing frames, but my project is going to be finished on HD. Is it possible to achieve this effect in telecine? Also besides changing the frame rate on the camera is there anything else that I should modify?


Thanks

John
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#2 Esteban Rodriguez

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Posted 21 May 2008 - 12:03 AM

I dont know about the telecine process and what that could do. But in order to achieve the strobe effect your looking for in camera would be not to change your frame rate, but to adjust you shutter angle to 90 or 45 degrees or whatever angle suits your film in particular

Hello,

I?m shooting a feature and I?m interested in using a strobe effect similar to the one that you get by shooting at frame rates such as 16 or 12 fps. This effect has been used by Robert Richardson in much of his work, particularly JFK and Januz Kaminski in Private Ryan.
I know this is usually done by optically re-printing frames, but my project is going to be finished on HD. Is it possible to achieve this effect in telecine? Also besides changing the frame rate on the camera is there anything else that I should modify?


Thanks

John


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#3 Michael Nash

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Posted 21 May 2008 - 12:14 AM

I dont know about the telecine process and what that could do. But in order to achieve the strobe effect your looking for in camera would be not to change your frame rate, but to adjust you shutter angle to 90 or 45 degrees or whatever angle suits your film in particular


A fast shutter (narrow shutter angle) and step printing are two different things. I think John is asking about step printing.

Many telecines will allow you transfer at slower frame rates to match your shooting fps. If you transfer your undercranked material at 24fps to a true 24p format, you can slow it doen in post and create the step-printed effect that way.
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#4 John Sprung

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Posted 21 May 2008 - 12:35 PM

I?m interested in using a strobe effect similar to the one that you get by shooting at frame rates such as 16 or 12 fps. This effect has been used by Robert Richardson in much of his work, particularly JFK and Januz Kaminski in Private Ryan.

There are two variables here, frame rate and shutter angle. Both are critical to the illusion of motion. Not enough frames per second, and you see the individual still images. Not enough motion blur, and you get the chattering strobe effect. In the old days it was called "skipping".

In your case, the best thing woud be to shoot some tests with the "B" team performing the kinds of motions you'll need. There are a lot of combinations to look at, so you can pick the one you like. "Ryan" was done by using a 45 degree shutter, IIRC.



-- J.S.
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#5 john torres

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Posted 21 May 2008 - 07:18 PM

Thanks for the responses,

The effect I?m looking for is more of a motion blur effect, not so much the staccato look of using a 45 degree shutter. In order to achieve this, is there a particular shutter angle I should use to create varying degrees of motion blur? Also I might be using the Arri 2c for some shots in the film. Can the shutter in this camera be adjusted for the effect?

Thanks,

John
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#6 timHealy

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Posted 24 May 2008 - 10:57 AM

I think the effect you are looking for like in JFK is shooting at 12 fps and transfer to video at 12 fps or optically print for film to create 12 fps. (I think is some cases Richard shot at 6 fps and transferred at 6 fps)

Can the HD camera you are using have a really long exposure time to recreate the effect on video? Since normal 24fps is something like a 50th or 60th of a second perhaps a 30th of second would work. Anyway you would need a longer exposure whether it was time or a wider than normal shutter opening on a mirror.

Video cameras are not my area of expertise but I would ask those questions.

Best

Tim
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#7 Michael Nash

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Posted 24 May 2008 - 03:37 PM

Can the HD camera you are using have a really long exposure time to recreate the effect on video? Since normal 24fps is something like a 50th or 60th of a second perhaps a 30th of second would work. Anyway you would need a longer exposure whether it was time or a wider than normal shutter opening on a mirror.


I think he's shooting 35mm and finishing on HD.

Undercranking the camera creates the longer exposure time needed for increased motion blur. An ordinary 180 degree shutter at 6 or 12 fps works just fine.
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#8 Michael Collier

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Posted 24 May 2008 - 07:09 PM

your making it too complicated. In telecine I transfer everything at 30fps. Do that and you will be fine. One frame on film will be one frame on the video, and you can tell the NLE to interpret the footage at a proper rate. In post slow the footage down to real time. If you shoot 6fps and your timeline is 24p then slow it down by a factor of 4 (25%). Make sure you keep frame blending off and you'll have the same effect as step printing. As an added bonus the telecine will be cheaper. You won't have to supervise and reset for a step transfer (if that's even possible) and since its 30fps, even normal 24p will fly through fasterthan real time, reducing machine time costs (and media cost if you have a lot of footage)
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#9 timHealy

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Posted 24 May 2008 - 10:44 PM

I think he's shooting 35mm and finishing on HD.

Undercranking the camera creates the longer exposure time needed for increased motion blur. An ordinary 180 degree shutter at 6 or 12 fps works just fine.


I'm sorry I just misunderstood. I thought he was shooting HD. But shooting film is easier. Just shoot at 6 or 12 fps or whatever and transfer at the same rate. It's that simple.

best

Tim
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