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Frame rate and the F3 camera

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Matt patterson
Frame rate and the F3 camera
on Sep 22, 2012 at 5:21:24 am

I'm prepping to shoot on the F3 with ki pro mini external recorder and am having trouble deciding a frame rate. I originally wanted to shoot at 24fps but the F3 doesn't have that option, the nearest option is the 23.98p but as a 2-3 pull down. I've heard there is alot of hassle when shooting in that mode, would it be easier for me to shoot it as 1080/25p?
Thanks guys I really appreciate your help.

Matt


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john sharaf
Re: Frame rate and the F3 camera
on Sep 22, 2012 at 6:33:55 am

Matt,

The reason there's no 24 is that audio would not sync to it. 23.97 is a convention that is really 24fps but allows recording and playback with sync sound. The KiPro does not record the pull down cadence, that is usually created in playback off of the finished timeline.

25fps is the frame rate used in countries with 50hz electricity vs 60hz here in the states, where it would be a mistake to shoot at 25fps.

Hope this helps!

JS



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Matt patterson
Re: Frame rate and the F3 camera
on Sep 22, 2012 at 10:41:21 am

Thanks John! You have a really great way of explaining technical stuff in a way that easy to understand THANK YOU ! I’m trying to wrap my head around the 2-3 pull down method, but I’m having trouble understanding the way it works would you be able to help me?


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john sharaf
Re: Frame rate and the F3 camera
on Sep 22, 2012 at 5:35:46 pm

Matt,

Motion picture projection is at 24 fps in a dark theater where persistence of vision (which is the minds ability to merge the separate frames into a smooth moving picture) makes it work. A conventional TV display works at 29.97 frames per second, with each frame made of two fields alternately showing half the screen height in alternating odd and even lines. This allows both interlace (where each field has a separate timebase) and progressive, where there are pairs of the same field.

To convert 23.97fps to 29.97, some frames are repeated twice and some three times (thus the 2:3 reference) in a cadence designed to be as smooth as possible. Simply put the 24 frames are extended to 30 frames within the same second. This was originally designed to exhibit programs shot on film at 24
to be shown on television.

Nowadays displays are capable of operating at many different framerates, but if they were to reproduce 24 at 24 you'd see a flickering image. So they basically double the sapling to 48 or 96 to fill in the blanks.

Another benefit of using 24 (assuming you like the film look of the motion) is that it uses less storage space. You can save as much as 60% when shooting 24p vs 60p (as in the original Panasonic Varicam).

Don't be confused by the whole number vs. fractional framerates; in the US (and other 60hz countries) 24fps really means 23.97, 30 fps means 29.97 and 60i means 59.94. The small fractional amount between the NTSC speed and the whole number is the area origionally in the TV signal that contained color information, and has carried over to this day. In PAL countries the frame rates arer whole numbers (25p and 50i).

Hope this helps,

JS



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Matt patterson
Re: Frame rate and the F3 camera
on Sep 23, 2012 at 8:14:06 am

Thank you John that helps alot!


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Richard Herd
Re: Frame rate and the F3 camera
on Sep 25, 2012 at 10:46:45 pm

Here's a web page to read: http://lurkertech.com/lg/video-systems/

and

http://lurkertech.com/lg/fields/


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