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24p vs. 30p vs. 60p Questions

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Clay Porter
24p vs. 30p vs. 60p Questions
on Aug 7, 2008 at 7:02:40 pm

I recently purchased a Sony EX1 camera and have some questions regarding the formats. I know that choosing what shooting format is a completely stylistic and project driven question but I had some technical questions about some of the formats...

1. I shoot mostly action (ie. fast pans, constant movement etc.) and found that the only way to get smooth, non jittery shots is to shoot 60p. This is fine as I am happy with the results but what exactly is 60p the only way to seem to be able to get a smooth shot? Also, In a 60p FCP timeline it shows 60 fps. Why is this as the footage is clearly not 50% of the real time. What exactly is 60p? Why shoot 60p?

2. I have seen some great footage shot with 24p but whenever I try and shoot with it the image is extremely gittery and flickery. It doesn't look smooth at all. Is this because my shutter speed is too high? Like I mentioned most of my subjects are sports, outdoors and I usually shoot with a shutter speed of 1/500. The same goes with 30p. The only way I can get smooth pans at 1/500 is with 60p. I am fine with this but i'm just wondering what I am doing wrong with my 24p and 30p settings.

3. Lastly, as I am shooting a lot of 60p footage I noticed that when I place the footage in a 30p timeline it seemingly converts the footage to 30p. Is this true? And when I use the 60p footage in a 60p timeline you can slow down the footage with no gitters or flickers exactly as you would be able to with interlaced footage. Why is this? If I were to mix 24p, 30p and 60p footage what should my timeline in FCP be? I assume the format that I have used the most.

Thanks for the help in advance. Any answers are appreciated.

Cheers,
Clay


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Craig Seeman
Re: 24p vs. 30p vs. 60p Questions
on Aug 7, 2008 at 10:43:13 pm

There's a lot to this so I'll start with a simple explanation and others can add details as they wish

60 "snapshots a second is greater temporal resolution. There's much debate over 720p60 vs 1080i60 but both have 60 snapshots a second. More snapshots per second more detail to the motion.

24 snapshots a second would be much lower temporal resolution. You're taking fewer snapshots so there's more motion traveled between frames that either isn't recorded or blurred.

Simply more frames per second, more shots of the moving objects, more motion detail.

There's also the impact of shutter speed but I'm starting out simple for you.

Shutter speed determines how much motion is captured in that frame. Fast shutter speed and you get that "Saving Private Ryan"juttery effect. Slow shutter speed and there's blur to the motion. With 24p you need to keep your movements slow and/or have a slow shutter speed.




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Clay Porter
Re: 24p vs. 30p vs. 60p Questions
on Aug 7, 2008 at 11:52:30 pm

Hey Craig,

Thanks for the reply.

So 60p is a better format then? It would seem this way. 60p has more infomation to it. And 60p is the most similar to HDV 1080i60 in terms of look. Is this correct?

Why can you not overcrank with 60p footage? When I want to overcrank I have to shoot 30p.

Say I am shooting all 3 formats, which timeline should I use? Should I just use the format that I have used the most in the project?

Finally say I am mixing HDV 1080i60, EX1 720p60 and EX1 720p30. What should I make my timeline in FCP?

Cheers,
Clay



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Stephen Schott
Re: 24p vs. 30p vs. 60p Questions
on Aug 8, 2008 at 1:19:39 am

Clay,
I just purchased an EX1 as well so I'm no expert, but one of the things that I can tell you is, if you have a choice (which it seems you do) choose a format and use that for all cameras. Mixing a HDV kinda screws that up a bit, but if you are working with an HDV camera that doesn't allow you to change format, for all intensive purposes I'd switch all my cameras to that format. Now saying that, if you are looking for a special look or something for a specific shot, then by all means change. But "normally" you keep all cameras on the same fps, progressive/interlace, shutterspeed, etc.. The reason I've found is it doesn't make one camera stand out from others. You don't want the viewer to say, "Hey, why does that one shot look jittery, while the others look perfectly smooth." A colleague explained a long time ago, "The best camera work is that which the viewer never notices."

When you've got family, everything is extra.


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Clay Porter
Re: 24p vs. 30p vs. 60p Questions
on Aug 8, 2008 at 1:40:19 am

Hey Stephen,

Thanks for the advice. I like the quote your colleague gave to you. Good stuff.

You say mixing and HDV format kind of screws things up but isn't that the point of the newest version of FCP, that you can mix formats/frame rates no worries?

Cheers,
Clay



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Stephen Schott
Re: 24p vs. 30p vs. 60p Questions
on Aug 8, 2008 at 2:18:57 am

For some that may be the purpose, but for some it is to help when they get stock footage from TimBukTu on one format but the rest of the project is all on XD at 1080i, 30fps, etc... It allows for it but that doesn't mean that is what you want to do. The only reason I say HDV kinda messes that up is HDV cameras have few choices, if any, with the kind of footage you shoot. So you tend to be stuck with whatever that camera shoots in. Some have a few choices, some don't. Less choices for you. That's all.

When you've got family, everything else is extra.


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Stephen Schott
Re: 24p vs. 30p vs. 60p Questions
on Aug 8, 2008 at 3:22:46 am

Also something that I've heard but never tested nor seen, if your VTR is a lower end, and it only records in 1080i, we'll say, and your shooting in 720p it can make things look messy... That is complete here-say, though. Never seen or tested but it makes theoretical sense.

Stephen

When you've got family, everything else is extra.


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Craig Seeman
Re: 24p vs. 30p vs. 60p Questions
on Aug 8, 2008 at 1:24:06 am

[Clay Porter] "So 60p is a better format then? It would seem this way. 60p has more infomation to it. And 60p is the most similar to HDV 1080i60 in terms of look. Is this correct? "

Don't use "better." One uses what one thinks is the best settings for a given job/purpose.
60p and 60i have the same 60 snapshots a second. For various reasons some prefer progressive, some prefer interlace. In this case it's 720p60 vs 1080i60. I prefer 720p60 because I like the 720 lines of progressive info per snapshot vs 540 alternate lines (2 separate fields of alternating lines) in interlace to equal 1080 lines.

[Clay Porter] "Why can you not overcrank with 60p footage? When I want to overcrank I have to shoot 30p"
The camera shoots a maximum of 60 frames a second regardless of mode. In overcrank it's handling a very high data rate. More like 87Mbps rather than 35Mbps.

[Clay Porter] "Say I am shooting all 3 formats, which timeline should I use? Should I just use the format that I have used the most in the project? "
Why would you deliberately shoot all three formats? You may have to do some conversions in Compressor (or other equivalent) since mixing these formats can make a bit of a mess in the timeline.

[Clay Porter] "Finally say I am mixing HDV 1080i60, EX1 720p60 and EX1 720p30. What should I make my timeline in FCP?
"

What's your goal and why are you mixing formats? My target guides my timeline use.




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Clay Porter
Re: 24p vs. 30p vs. 60p Questions
on Aug 8, 2008 at 1:36:17 am

Hey Craig,

Thanks again for the reply.

I am not deliberatly shooting all 3 formats. I will however be mixing two 30p and 60p as I cannot over crank with 60p. 60p however is the format I will be using most. I shoot sports documentaries where we occasionally mix in TV footage of the event that is neither 30p nor 60p and usually BetaCam or another non HD format. Basically, I am just trying to weigh my options and see what timeline I should use.

Is it that uncommon to have a project that contains both 30p and 60p footage?

Thanks,
Clay



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Don Greening
Re: 24p vs. 30p vs. 60p Questions
on Aug 8, 2008 at 3:42:06 am

[Clay Porter] "Basically, I am just trying to weigh my options and see what timeline I should use. "

Just use the 60p timeline if that's the vast majority of your footage. You can create any old timeline in FCP 6 and when you drag a 60p clip into it FCP will ask you if you want to change the sequence settings to match the clip settings. Just say yes. Any other video format after that will automatically be conformed for that timeline. Dirt simple.

[Clay Porter] "Is it that uncommon to have a project that contains both 30p and 60p footage? "

It's not uncommon at all and I do this all the time. Most of my footage is 1080p 30 and I just drag the 720p stuff right in and it generally re-scales to fit. Remember that the EX 1080 stuff is square pixels and the 720p stuff is anamorphic. Doesn't matter if it's over/under cranked or straight 60p: It's all anamorphic. Most of the time FCP gets it right and scales everything to fit the sequence settings. The odd time it doesn't it's just a simple matter of changing the scale parameters for that one piece. If you have more of the same that didn't scale properly you can copy that clip's attributes and then paste them on to all the other clips.

Hope this helps.

- Don



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Alan Okey
Re: 24p vs. 30p vs. 60p Questions
on Aug 8, 2008 at 7:32:05 pm

[Don Greening] "the 720p stuff is anamorphic"

That's not the case with XDCAM EX, only with DVCPRO HD. 720p in XDCAM EX land is full-raster 1280x720 square pixel. DVCPRO HD is 960x720 anamorphic.


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Stephen May
Re: 24p vs. 30p vs. 60p Questions
on Aug 20, 2008 at 6:03:33 am

In my experience, it is effective to do the following in order to conform your 60fps media for slow motion. First, Cinema Tools is the app that I use to prepare anything that I shoot into slow motion. To do that with EX1 footage, I first have to save the quicktime VBR clip (variable bit rate) to a CBR clip (constant bit rate). That can be done in quicktime pro, or in compressor. Once that's done, each of your EX1 converted clips can be opened in Cinema Tools and conformed to either 24 fps - extremely slow motion, or 30 fps - smooth slow motion.

Otherwise, you will see what you mentioned early on in this thread, that it all looks like it's in real-time, albeit smooth. The rest of the deal about why mix frame rates, or the idea that it all depends on what your goal is - that's the thing; I can think of many reasons that I'll shoot different frame rates for a single project. FCP is really good about that, and you grow when you're thinking outside of the box, or outside of "that's what everybody else does..." type constraints. If your work looks good, you know it, and so will everyone else.

-Stephen (it's late, I got carried away...)

Stephen May
Keystone Media Productions
Freelance Videographer


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Arnljot Bringedal
Stephen:
on Aug 20, 2008 at 6:06:28 pm


EX1 slowdowns in cinema tools is something many here ask about.

I myself have problems grasping cinematools.

Maybe you could do the Cow a big favour and post an easy tutorial with some screenshots?




*** Norwegian videojournalist & Editor***


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Stephen May
Re: Stephen:
on Aug 21, 2008 at 4:27:55 am

Arnljot - let me look around on COW to make sure this isn't already covered, for example in the Final Cut Studio 2 forum (assuming there is one). If there isn't anything yet, I'd be happy to. Thanks -s

Stephen May
Keystone Media Productions
Freelance Videographer


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Stephen May
Re: Stephen:
on Aug 21, 2008 at 4:29:38 am

Arnljot - let me look around on COW to make sure this isn't already covered, for example in the Final Cut Studio 2 forum (assuming there is one). If there isn't anything yet, I'd be happy to. Thanks -s

Stephen May
Keystone Media Productions
Freelance Videographer


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