Strobe differences between 24 P and 24Pa

J

Joseph_Murray

New member
Is there any difference between 24P or 24 P-a (improvement) in the strobing I see in vertical elements when doing dolly or panning, even at slow film safe speeds? I just aquired a DVX-100A and while testing it in 24P-a, even using 1/32nd shutter, it seems to my eye that the strobing in vertical elements is much more prevelant than when shooting film. The camera is a great tool considering the cost vs. image quality, but I was wondering if there was something I could do to improve this. I know that shooting 30fps will clean this up but I am partial to the "film look". If I shot at 30fps and used a plug in filter to bring it back to 24 fps will that show any improvement? Thanks, Joe
 
Re: Strobe differences between 24 P and 24Pa

First off, you'll still maintain somewhat of a film look with the 30P. It's a very underrated shooting mode.

But you have a DVX100, so of course you don't want to shoot 30P all the time. The motion rendering on the 24pA is inevitably going to be different than 24p normal when viewed straight on an NTSC monitor because they use different pulldown methods. The 24p normal is made for straight transfer to video, the 24pA is not--it's for film output.

Also, the default vertical detail setting for F6 (24pA) is THIN, and you should always use THICK for video output. You can still use 24pA--just change vertical detail setting & be sure that you're working in an NLE that can remove the 24pA pulldown & output to 2:3:2:3.
 
Re: Strobe differences between 24 P and 24Pa

..true . unless you are going to pull the 24pa down to a true 24p file for film out or web or 24pdvd or somthing, even if just to edit in 24p, and output back with 2:3 telecine. 24pa without the pulldown isnt supposed to look smooth . its supposed to look smoth after its pulled down, and will be smooth after doing pulldown and a 2:3 telecine(in other words once you remove the extra frames from the 24pa as its designed to be done with, it will be smooth- 24pn is designed to be smooth 24p telecine without any frame removal, but is more difficult to get full quality true 24p from). . the 24pn mode does the standard 2:3 telecne frm the beginning, but loses quality when converting to 24p via firewire edit.

what needs to be understood here is that the although the camera takes 24progressive frames per second, it records those frames into a 29.976 timeline so that you can use standard ntsc equipment. it does this in 2 different ways.
the 24pn mode uses the standard film (24p) to 29.976 ntsc telecine which uses the 2:3 cadance and looks very smooth, and is what you see on any film transfered to vhs or non 24p dvds. or television broadcast. the 24pa method of recording 24p into a 29.976 timeline isnt supposed to look smooth as is , its supposed to do the best job of preserving the original 24 progressive frames, so that you can extract them from the 29.976 timelane and create a 24p timeline with the original 24p fps.. from there you can edit and export, and even add the 2:3 telecine just like you wuld with a film, to make it ntsc.
but if you dont go through that proccess it wont look smooth, and its not supposed to.
 
Re: Strobe differences between 24 P and 24Pa

[quote author=Joseph_Murray link=board=Events;num=1075480261;start=0#0 date=01/30/04 at 08:31:01]If I shot at 30fps and used a plug in filter to bring it back to 24 fps will that show any improvement? [/quote]

There is no good way to convert 30P to 24P. You're asking for trouble by thinking along those lines.

24PA motion is a bit more stuttery than 24PN. 24PN smoothly distributes the 24 frames across the 60i fields as evenly as possible. 24PA doesn't even try: it puts out four full frames (which NTSC plays back 20% too fast) followed by one split frame (which sort of brings the whole process to a halt), followed again by the 4 full frames, etc. So 24PN will be a bit smoother on a television. I don't know if that'll resolve your worries about stuttering, but definitely try it and see.
 
Re: Strobe differences between 24 P and 24Pa

First of all, thanks everyone, for the reply.

let me get this straight...

1. If i view 24pA on the camear direct out to a video monitor it will look strobe-y.

2. If I take that 24P-a footage into FCP 4.1 with the proper settings (if anyone wants to chime in on the workflow I would much appreciate it) and back out to the camera and look at it on a monitor, it won't be as strobe-y?

3. I might as well save the trouble and shoot 24p on this project (music video, no film out) and I will see smoother results.

Are the above statments true?
 
Re: Strobe differences between 24 P and 24Pa

The images in the LCD monitor will always look strobing like. No matter which one you choose. You need to see it on a TV monitor 8)
 
Re: Strobe differences between 24 P and 24Pa

What I meant by to ask in...

"2. If I take that 24P-a footage into FCP 4.1 with the proper settings (if anyone wants to chime in on the workflow I would much appreciate it) and back out to the camera and look at it on a monitor, it won't be as strobe-y?"

....is will FCP import and export process output back with 2:3 telecine to the camera and smooth the image out?

BTW I did view the 24P-a on a monitor, not the lcd screen and it looked very strobe-y on verticals.

thanks Joe
 
Re: Strobe differences between 24 P and 24Pa

im not sure if fcp has telecine ability .. i think it does, but i dont use it . i use dvfilmmaker or aftereffects to convert 24pa to true 24p files, and the premiere pro to edit..somtimes 6.5.  then i used dvfilmmaker or aftereffects to proccess the 24p edit to a ntsc version with a 2:3 cadance. and keep the true 24p version for web and film or other apps.  fcp can do a pulldown for the 24pa material from the cam in realtime by using the 2:3:3:2 pulldown in realtime, and just not displaying the other frames. i think it can take the 24p edit, and export it with a different ntsc standard 2:3 output telecine. ..can some fcp user confirm whether fcp4 can do the telecine on output for me?
 
Re: Strobe differences between 24 P and 24Pa

..however joe i did just wrap a commercial shoot which i did in 24pn because i didnt really need 24pa for the project.. wroks great..looks great.. !
 
Re: Strobe differences between 24 P and 24Pa

[quote author=Joseph_Murray link=board=Events;num=1075480261;start=0#4 date=01/30/04 at 11:41:43]
1. If i view 24pA on the camear direct out to a video monitor it will look strobe-y.

2. If I take that 24P-a footage into FCP 4.1 with the proper settings (if anyone wants to chime in on the workflow I would much appreciate it) and back out to the camera and look at it on a monitor, it won't be as strobe-y?

3. I might as well save the trouble and shoot 24p on this project (music video, no film out) and I will see smoother results.

Are the above statments true?[/quote]

Generally, yes. BUT: it's not that big of a difference. 24PN is a little smoother, but it's not night-and-day smoother. 24P motion strobes -- that's part of the deal. You have to really control camera movement to minimize it. So 24PN will be a little smoother, or 24PA that's been processed, had 2:3:3:2 pulldown removed, and had 3:2 pulldown inserted, will be a little smoother. But it's not a significant amount, it's just a little smoother.
 
You must log in or register to reply here.
Back
Top