Stuttering Motion?

C

csuchorsky

Member
Hi Everyone,

Got a question about the HPX170. I've been using the DVX100A for the past 5 years. I love the camera. It has been absolutely amazing. I made the jump to the HPX170 recently, but have noticed that the motion stutters in FILM CAM mode. I'm planning to shoot a new documentary soon and was planning to shoot the doc at 1080 24pa. That's the advanced mode right? That pulls down the extra frame?

Am I understanding this right? In 1080 mode, you're still recording at 1080i. If you record at 1080 24pa, when I import to FCP, it'll pull down the extra frame and make it 1080p. Is that correct? What about 1080 30p? That's still recording at 1080i right?

So two things...

1. Can someone explain the 1080 format on this camera?

2. Anyone have any solutions for this stuttering motion?

Thanks!
 
1) The 1080 mode works exactly the same way the DVX does in 480 -- it records 24p and 30p in a 60i stream, and you treat the footage the same way.

2) Film Cam mode won't affect anything that would make the motion stutter, EXCEPT that the style of shutter changes. "Stuttering" motion may be the result of a high shutter speed, which would be a low shutter angle (if it's below 100, you might start noticing it a lot).
 
is this your first time shooting 24 frames? the "24p cadence" catches many new users by surprise...
 
Yeah this is my first time shooting 24p. I shot my last doc at 29.97 with a CineLook. The motion was great. This 24p image is driving me nuts. I just found this....

"Also because the 2:3:3:2 pulldown scheme was devised in order to make pulldown removal for editing in native 24p more efficient, the pulldown arrangement is not ideal for watching footage. There can be exaggerated stutters in motion, because the frames which are split into three fields are not only onscreen for 50% longer than the other frames, they are back-to-back. As such, 2:3:3:2 pulldown should be used only when a native 24p edit is planned, and not for final viewing. This includes when shooting the footage initially, and also when printing back to tape from an NLE"

How is 24p not good for final viewing?
 
This may or may not apply, but just in case....

Have you checked the OIS setting on the camera? That one got me early on.....Engage OIS if your image is subject to excess strobe, and see what happens. Just a thought.
 
csuchorsky said:
Yeah this is my first time shooting 24p. I shot my last doc at 29.97 with a CineLook. The motion was great. This 24p image is driving me nuts. I just found this....

"Also because the 2:3:3:2 pulldown scheme was devised in order to make pulldown removal for editing in native 24p more efficient, the pulldown arrangement is not ideal for watching footage. There can be exaggerated stutters in motion, because the frames which are split into three fields are not only onscreen for 50% longer than the other frames, they are back-to-back. As such, 2:3:3:2 pulldown should be used only when a native 24p edit is planned, and not for final viewing. This includes when shooting the footage initially, and also when printing back to tape from an NLE"

How is 24p not good for final viewing?
Click to expand...

24pA isn't great for viewing. 24p standard - with 2:3, not 2:3:3:2 pulldown -- is how all 24p fps material is shown on NTSC TV.

If you shoot 24pA, you want to edit it AS 24p first, then output it either as straight 24p (like to DVD or Web format), or as NTSC with 2:3 pulldown (tape). (There are other possibilities, of course, but those are the common ones.)
 
24p with 2:3 exhibits telecine judder on a 60Hz-scan TV, and for many Europeans it looks horrible. 24p with 2:3:3:2 exhibits even more pronounced telecine judder, which is why it is not good for final viewing. To watch 24p the way it is shown in a movie theater you need a TV with 48Hz or 72Hz scanning rate.

24p also stutters by itself, and if filmout or converting to 50Hz is not required, then 30p may be a better option.

P.S. Why would not you use 60p for a documentary? A "reality look" for a factual show seems like a good idea to me. Later you will be able to convert it to 60i if needed, or to 24p, which will look decent enough for filmout.
 
Europeans aren't watching 60 Hz TVs. The process for viewing 24 fps material on a 50 Hz system is very different.

Choice of frame rate should be entirely aesthetic. Do it because that's how you want it to look.
 
David Jimerson said:
The process for viewing 24 fps material on a 50 Hz system is very different.
Click to expand...
They watch 25p instead.

David Jimerson said:
Choice of frame rate should be entirely aesthetic. Do it because that's how you want it to look.
Click to expand...
24p is a worldwide standard partly because it converts well to 50 and 60 Hz systems. 25p is not bad too. 30p is not that flexible, so it is not just about personal preferences.
 
Cranky said:
They watch 25p instead.
Click to expand...

Correct. They speed up 24 fps material 4% so that it, in effect, becomes 25p. That's the most common way of doing it. You don't get the same kind of possible flicker or judder as a 2:3 pulldown cadence may possibly get you.


24p is a worldwide standard partly because it converts well to 50 and 60 Hz systems. 25p is not bad too. 30p is not that flexible, so it is not just about personal preferences.
Click to expand...
The point is, you choose what you want it to look like first, and worry about technical considerations as you have to. If 30p best serves your artistic goals, then choose 30p. There are ways of making anything work; worry about it when and if it becomes a concern. For example, Scrubs, for most of its run, was shot on 30 fps film, which is for all intents and purposes 30p when it comes to the problems converting to 50 Hz. They chose it because that's what they wanted it to look like. But they still watch Scrubs in the 50 Hz world. The same can be said of Friends.

In an artistic field, the technical should serve the art, not the other way around.
 
I figured out one of the problems. Shutter speed was off. i didn't know 1/48 now means 180.0 d...

Alright, new question...the HPX170 shoots 1080i 24p and 30p and converts it to 60i. When I import this into FCP, should I be importing at 1080i/60i?

The HPX170 shoots:

1080i/60i - 1080i/30p - 1080i/24p - 1080i/24PA

FCP has import settings for 1080i60 - 1080p30 - 1080pA24

What goes with what here? There's no import setting in FCP for 1080i/24p so I'm guessing it needs to be imported at 1080i60 because it's converted to that in camera. But then that means 1080i/30p would need to be imported into FCP as 1080i/60 as well because it's converted in camera as well. So then why does FCP have an import for 1080p30?
 
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