difference between 23.98 and 24 frames?

[John Sharaf]

Zeliha,

The real question is “what’s the difference between 59.94 and 60?”

This all started when color was introduced to the broadcast signal. The additional requirement of the “color burst” meant that the video frame rate had to adjusted to 29.97 to fit it all in (basically 1000 divided by 1001).

Since that time all NTSC color video has been at the “fractional” frame rate of 29.97.

Even though your HD video is not NTSC, the reality is that it will be downconverted to be editing (offline) and exhibited on Standard Def broadcasts, so the frame rates must conform to the NTSC standards. There will eventually come a time (many years from now) when these fractional speeds will go away, but only after abandoning the current archive of NTSC origionated sync sound material.

It’s really about the sound now, because all TV sound is recorded, edited and transmitted at this 29.97 frame rate; if you shot the picture at the “whole” frame rate, the sound would be out of sync.

The confussion comes in the camera speed setting sections of the modern HD cameras. Panasonic has made it simpler than Sony, by allowing you to set the “systems frequency” at either 59.94 or 50/60 (depending on the particular model). Once this setting is established the frame rate is referred to by the whole number thereafter (24, 25, 30 or 60). Suffice it to say that you always want the 59.94 setting if you are shooting for a NTSC market (or filmout that will be edited in a 24fps timeline). The only reason to set the camera at 50/60 is to allow a 25 or 50 frame rate for PAL.

The Sony cameras offer all the speed in the selection menu (23.97, 24, 25, 29.97, 50, 59.97) and some of the older cameras offer 30 and 60 too, but these would never be used and have been eliminated from the F900R menu, acknowleding how long it will be before NTSC disapears completely.

There is one occasion when you might consider shooting “hard” 24; that is when you are using your HD camera to shoot MOS (without sound) material for filmout that will be inserted directly into A&B rolls of film negative for conventional film printing, but this too is becoming almost moot, as most films are finished electronicly in a DI (Digital Intermediate) process and only “filmed-out” or transfered to actual film at the very last stage.

It might be helpful to know that even film that is shot at 24fps essentially becomes 23.97 when converted to video/digital in the telecine (even though the with the pulldown it more accurately is described as 29.97).

Suffice it to say that this is a very esoteric discussion and the real answer can be summarized to be as I stated earlier that you always want to shoot the “fractional” speeds (even though they might be referred to as whole numbers, unless you are shooting for PAL or 25fps filmout (European Standard – because the power there runs at 50hz vs. our 60hz, so the timing is different, meaning for example our electric clocks would run slow there and their clocks fast here!).

I hope this helps.

JS

[Robin Probyn]

Hi there

Thanks this also has helped me have a better understanding.Iam begining to get my head around it,but have another question.

Could you explain the difference,pro,s and con,s of 24PA,I think it(the A) stands for adavnced and is 2-3-3-2
rather than 2-3.?? I know this is something to do with removing flagged frames from the 59.94 to make 23.98.Or am I completely wrong…

Thanks for your time again

[Zeliha Bozkurt]

Hi John

Thanks a lot for taking all that time for the detailed explanation. It really does makes sense more than ever.

Cheers

Zee 🙂

[Zeliha Bozkurt]

Hi,

I can’t rally explain your question, as myself is trying to understand this all. But there are few websites I found helpful. Hope this helps.

https://www.zerocut.com/tech/pulldown.html

https://www.projectorpeople.com/resources/pulldown.asp

below is for Final Cut

https://www.kenstone.net/fcp_homepage/24p_in_FCP_nattress.html

and this one is for avid

https://www.zerocut.com/tech/p24.html

Zee.

[Robin Probyn]

Hi Zee

Thanks for the sites,Ive got some idea now from other investigation on the net.

Thanks!