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Frame rate issue


Fernando Alves

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Hello,

I am an editor. I have a doubt. Sometimes I receive from the DIT footage in 23,976 and it is slow motion. What am I missing here? The video is in slow motion, but if I look in the information it shows 23,976? Can anyone tell me or show a good article about it?

 

Thansk a lot,

Fernando Alves

Editor

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2 hours ago, Fernando Alves said:

Hello,

I am an editor. I have a doubt. Sometimes I receive from the DIT footage in 23,976 and it is slow motion. What am I missing here? The video is in slow motion, but if I look in the information it shows 23,976? Can anyone tell me or show a good article about it?

 

Thansk a lot,

Fernando Alves

Editor

What does it say in the file metadata .. is there any audio .. I guess it has to have been shot over cranked with base frame rate 23.98p..  ask the person who shot it in the first place ? 

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On 7/8/2020 at 5:05 PM, Fernando Alves said:

Hello next month I am going to use Sony Alpha 7 iii  and  Sony Alpha 6 300. Last time I use Alpha 7 iii didn't like the way I set up my camera. Have seen some tutorials in Youtube, and set up my camera following one of these tutorials. Does anybody here like Sony Alpha? Maybe anybody can help me here. Is there a solid tutorial about  how to setup my picture profile?? Wacthing those tutorials I notice that people are very particular in the way to setup their Pircture Profile. 

In this next month job, I will shoot in a small studio a model of hands. Which light should I rent to get a nice skin color with this camera? 

 

Thanks a lot.

I found that the film was shoo in 47 frames per second and project time base in 23,976. Why DPs choose this setup? 

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Because it’s a slow motion shot so the project frame rate is 23.976 fps. If the project frame rate was 47 and he shot at 47, then the speed would appear normal, not slow motion.

47 fps only looks slow motion if it’s played back at 23.976 fps (or any speed less than the shooting rate.)

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Most cameras  have a built in over crank record mode ..Sony its called S&Q (slow and quick).. so your "baking in" the high or low frame rate but the camera knows the base rate, so that shot /file will actually play back in slo motion / fast motion .. straight from the camera card .   47 frames no idea why  .. 50 fps is common in 50Hz countries .. ie half normal speed if base rate is 25p..   you usually doubt up (180 degree ) the shutter speed too.  eg 50fps = 1/100th  or what ever will cut down the risk of flicker of AC powered lights.. 

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Oddball framerates can't be used as a base framerate so one chooses something which is standard as the base and then the recorded frames are fit to that. The frames are never chanced, only the metadata which sets the playback speed of those same frames which stay intact.

This type of arrangement is very common with all cameras which can do oddball framerates. The actual sensor framerate is not necessarily stored in the metadata so you need to ask from the dp what the original was if you need that information. 

The 23976 is to ensure post compatibility, I would not try to change the clip metadata to 47fps playback speed 

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I would guess that ‘47fps’ in this case is actually 47.95fps, or exactly 2x the frame rate of 23.976. This would be a fairly normal over-cranked frame rate to shoot at for 2x slow motion.

Generally if you’re shooting on a digital camera in a 23.976fps timebase, then the variable speeds available will also be fractional frame rates, even though in practice everyone still refers to them by their whole numbers (i.e. 30fps [29.97], 48fps [47.95], 60fps [59.94], 120fps [119.88], etc).

There’s no difference in look between the two, other than perhaps a slight chance of flicker in some light sources and displays. Some camera systems like Red will accurately display the fractional frame rate, while others will not. Red will also allow you to manually set a whole number frame rate, overriding the default fractional one. Check the metadata if you want to know what your camera actually recorded.

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