# How to convert 23.98 to 29.97 in post and will look natural.

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### #1 etiennecaron

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Posted 11 September 2008 - 09:17 PM

We will shoot with the Red camera a video clip and we cannot shoot 29.97 fps in 4K since we need the Drive and we only got the compact flash that only allow 23.98 or 24 fps.

We decide to shoot 4K (not 29,97 3K) in 23.98 fps and in post add the pulldown to reach the 29.97 fps. We did somes tests on FCP and we see cleary the duplicate frame and its not natural.

What do people do in telecine when they shoot a video clip in 16mm, 24 fps, and they convert it to NTSC 29.97 ? Its look so natural, i dont understand that i cannot do the same with my Red footages convert to ProRes for exemple.

Anyone have a secret to do the smooth conversion from 23.98 to 29.97 fps in post ?

thanks millions times !
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### #2 John Sprung

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Posted 12 September 2008 - 01:58 PM

What happens in going to NTSC is called 3-2 pulldown. NTSC consists of 60 interlaced fields per second, not 30 complete frames. So, they make 3 fields from the first film frame, two from the next, and keep on alternating 3-2-3-2-3-2 like that. Every two film frames become five video fields, so at the end of a second you have 2x12 = 24 film frames and 5x12 = 60 video fields. (And it all works exactly the same with the goofy point-nine-something numbers, too.)

Going from Red's 24 or 23.976 to NTSC or to interlaced HD should work just as well. The place you'd have trouble is going to true progressive at 30 or 29.97 fps.

-- J.S.
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### #3 Peter Moretti

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Posted 13 September 2008 - 05:21 AM

John, so what you're saying is that the 3:2 pulldown works well for going from 24P to 60i but not to 30P.
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