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29.97 v. 23.98


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#1 Jerry Doran

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Posted 10 August 2009 - 09:06 AM

A few basic questions regarding time base:

If you are shooting something for broadcast, is there any advantage to shooting 23.98 over 29.97? Many people seem to think there's some visual advantage to shooting 23.98 and then pulling down later in post to 29.97. True?

Which time base should you choose for web video?

Is it always preferable to shoot with the decimal offset? Are there any instances where it would be okay to shoot straight 24 or 30?

Thanks.
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#2 Matt Read

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Posted 10 August 2009 - 12:19 PM

Shooting 23.98 will give you a slight film-look over 29.97, in that you'll be shooting at (about) the same frame rate as film. That's the only difference. Your images will still look like they originated on video, because they did. If you know what you're shooting will end up on broadcast TV, you'll want to shoot 29.97, because that is the frame rate it will be played at when broadcast.

With web video, it doesn't really matter what time base you use, because the video you shoot will be heavily compressed before being put on the web. Any differences between the time bases would most likely be imperceptible.

There is no such thing as 24 or 30 fps, unless you are shooting on film or live in the 1950s. Back when television was all black and white, it did broadcast in true 30 fps. However, when color was introduced, there was no way to keep the 30 fps frame rate and add color while keeping the same signal size. So, to keep the same signal size and prevent everyone from having to buy new TVs, part of the signal was devoted to color and thus the frame rate had to be slowed to 29.97 to accommodate the new color information and now we're stuck with these silly frame rates. Whenever you see 24 or 30 fps, it really means 23.98 or 29.97 respectively.
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#3 Brian Dzyak

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Posted 10 August 2009 - 02:49 PM

Shooting 23.98 will give you a slight film-look over 29.97, in that you'll be shooting at (about) the same frame rate as film. That's the only difference. Your images will still look like they originated on video, because they did. If you know what you're shooting will end up on broadcast TV, you'll want to shoot 29.97, because that is the frame rate it will be played at when broadcast.

With web video, it doesn't really matter what time base you use, because the video you shoot will be heavily compressed before being put on the web. Any differences between the time bases would most likely be imperceptible.

There is no such thing as 24 or 30 fps, unless you are shooting on film or live in the 1950s. Back when television was all black and white, it did broadcast in true 30 fps. However, when color was introduced, there was no way to keep the 30 fps frame rate and add color while keeping the same signal size. So, to keep the same signal size and prevent everyone from having to buy new TVs, part of the signal was devoted to color and thus the frame rate had to be slowed to 29.97 to accommodate the new color information and now we're stuck with these silly frame rates. Whenever you see 24 or 30 fps, it really means 23.98 or 29.97 respectively.


Hmm... that's not entirely correct.

You can shoot at any frame rate you like and post the same way. If/when it goes to broadcast, then it will be "altered" if necessary. It is categorically NOT necessary to only shoot 29.97fps if going to broadcast. If that was true, then about 99.99% of what I've shot in the past seven years or so would've been for naught.

Higher framerates give "sharper" more "videolike" images, so 23.98fps is more film-like much more than 29.97 or 59.94. While it isn't film, it can look film-LIKE if shot and posted by competent professionals.

24 and 30 do exist but are not typically used for reasons having to do with sound and posting issues. From my experience, the only reason to ever shoot true 24 would be for a straight film-out. Keep in mind that many pro-sumer cameras SAY that the settings are 24fps but they are just using shorthand and the camera is really A) capturing in 23.98 or B) capturing in 60 and using various techniques to give you the look of 24.

30fps video was the standard until color, but do to noise (a buzz in the audio), 29.97fps was introduced to take care of it (which then introduced the need for Drop Frame and NDF)

If a Producer ever asks you to shoot in 24fps or 30 or 60 (any whole number), be sure to clarify because typically they don't know the difference and the Editors will be very upset with YOU for not shooting in 23.98 or 59.94.

So, you can shoot in any format and frame-rate you choose BUT it is always best to double-check with whoever is posting the material to make sure that they can handle whatever you give them and that it will deliver the desired look.
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Gamma Ray Digital Inc

Aerial Filmworks