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If I am going to de-interlace in post...should I increase the detail setting the menu?


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#1 Morgan Peline

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Posted 02 May 2009 - 12:30 PM

Hi,

I'm shooting a drama on an AG-HPX500. My director, who is a former editor, absolutely hates in-camera 25P, so she simply wants to shoot 10801/50i and then de-interlace in post. She says the resolution of the image goes down when you do this...

So should I increase the detail setting in the menu? If so, should I use the maximum?

I don't have the chance to test...

Thanks!
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#2 Saul Rodgar

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Posted 02 May 2009 - 12:52 PM

Hi,

I'm shooting a drama on an AG-HPX500. My director, who is a former editor, absolutely hates in-camera 25P, so she simply wants to shoot 10801/50i and then de-interlace in post. She says the resolution of the image goes down when you do this...


It is kinda confusing, they way you asking the question. Does the director think the loss of resolution happens when you shoot on-camera 25p or when you shoot 1080i 50 and deinterlace in post? Part of the problem is that this kind of thing is completely subjective. The perception of loss of resolution, deinterlaced video footage looking "better" than progressive, etc. These are all subjective points of view, to a point.

Quite honestly, the best thing to do is to run a test and find a solution both of you are happy with.

Edited by Saul Rodgar, 02 May 2009 - 12:53 PM.

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#3 Morgan Peline

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Posted 02 May 2009 - 01:19 PM

It is kinda confusing, they way you asking the question. Does the director think the loss of resolution happens when you shoot on-camera 25p or when you shoot 1080i 50 and deinterlace in post? Part of the problem is that this kind of thing is completely subjective. The perception of loss of resolution, deinterlaced video footage looking "better" than progressive, etc. These are all subjective points of view, to a point.

Quite honestly, the best thing to do is to run a test and find a solution both of you are happy with.


Basically she has has shot a lot of film so is used to the way a film camera's motion looks.

When she looks at 24P or 25P, she hates the way the motion looks on monitors and TVs and feels the motion doesn't looks like film and so looks 'fake' (not like a real film camera).

So basically when she shoots on video, she always shoots interlaced and then de-interlaces in post. But she says the only disadvantage of doing this is that the image resolution goes down (1080 lines down to 540 lines...)

(This whole area of progressive vs. interlaced is always a minefield for me...)

So I am wondering if I increase the detail in the camera menu if this will help the loss of resolution from the deinterlace.

I don't have time to test unfortunately...

Thanks
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#4 Phil Connolly

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Posted 02 May 2009 - 01:43 PM

Not used that camera, but increasing the detail in camera usually gives the image a ringing edgy digital look, I don't think would be removed by de-interlacing in post, as is only going to soften the vertical axes.

But the effect of de-interlacing footage 50i to my eye's results in the same motion as shooting 25p in the first place. As de-interlaced footage doesn't look truly filmic either, since no mechanical shutter is involved. The D20 is the only camera I've worked with that really nails the filmic feel when it comes to motion. As far as I can tell looking at lots of de-interlaced footage it looks pretty fake as well - compared to film - only with added softness and aliasing.

What could be an issue is the 25p effect always looks more extreme when your watching it live on the set. I've always felt that it looks fake when your shooting it - I guess its just seeing the motion on a monitor looking jerky compared to the live action actors - also in the same room. But when I'm editing the footage it looks fine and much less jerky then how it seemed during the shoot - so maybe thats part of reason why she may have an issue.

Is it the motion that she doesn't like or the sharpness?
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#5 Morgan Peline

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Posted 02 May 2009 - 01:52 PM

Not used that camera, but increasing the detail in camera usually gives the image a ringing edgy digital look, I don't think would be removed by de-interlacing in post, as is only going to soften the vertical axes.

But the effect of de-interlacing footage 50i to my eye's results in the same motion as shooting 25p in the first place. As de-interlaced footage doesn't look truly filmic either, since no mechanical shutter is involved. The D20 is the only camera I've worked with that really nails the filmic feel when it comes to motion. As far as I can tell looking at lots of de-interlaced footage it looks pretty fake as well - compared to film - only with added softness and aliasing.

What could be an issue is the 25p effect always looks more extreme when your watching it live on the set. I've always felt that it looks fake when your shooting it - I guess its just seeing the motion on a monitor looking jerky compared to the live action actors - also in the same room. But when I'm editing the footage it looks fine and much less jerky then how it seemed during the shoot - so maybe thats part of reason why she may have an issue.

Is it the motion that she doesn't like or the sharpness?


Yeah, she hates the juddery motion. And she is adamant that de-interlacing in post has a nicer looking motion than 25P...

My issue is that you end up getting 540 lines instead of 720 lines.

(Does progressive only ever look good on a film-out? Why does it always look so weird on monitors?...Is it because so many monitors are interlaced?)
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#6 Phil Connolly

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Posted 02 May 2009 - 02:21 PM

Yeah, she hates the juddery motion. And she is adamant that de-interlacing in post has a nicer looking motion than 25P...

My issue is that you end up getting 540 lines instead of 720 lines.

(Does progressive only ever look good on a film-out? Why does it always look so weird on monitors?...Is it because so many monitors are interlaced?)



I do agree that progressive can look weird on monitors, but I tend to notice it more when I'm watching a live feed off a camera. I've been on shoots, when the cameras switched to progressive, everyone looks at the monitor and goes eek thats a bit extreme. But the productions always looked fine in the edit suite - its as if our brains are fine with recorded progressive images and are confused when watching it live. I also find entertainment TV looks 'wrong' when its been de-interlaced, I am watching time team right now - it looks wrong.

That said if you can't convince her to shoot 25p, 540 lines though not ideal, its still ok. I've seen a few Z1 productions that were de-interlaced in post and still looked reasonably sharp. Whats the intended release format - film out? TV or some flavor of digital?
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#7 Morgan Peline

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Posted 02 May 2009 - 03:06 PM

I do agree that progressive can look weird on monitors, but I tend to notice it more when I'm watching a live feed off a camera. I've been on shoots, when the cameras switched to progressive, everyone looks at the monitor and goes eek thats a bit extreme. But the productions always looked fine in the edit suite - its as if our brains are fine with recorded progressive images and are confused when watching it live. I also find entertainment TV looks 'wrong' when its been de-interlaced, I am watching time team right now - it looks wrong.

That said if you can't convince her to shoot 25p, 540 lines though not ideal, its still ok. I've seen a few Z1 productions that were de-interlaced in post and still looked reasonably sharp. Whats the intended release format - film out? TV or some flavor of digital?


It's a 30 minute short that will form part of an 'omnibus' art-house feature film. It will probably go to DVD and may also be projected digitally for festivals. Might even make a print eventually if it gets funding...
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#8 John Sprung

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Posted 02 May 2009 - 07:03 PM

The way motion looks in 25p would depend on the exposure duration per frame, or shutter angle in film terms. Using a 180 degree shutter = 20 millisecond exposure will get you closest to the look of film. Shorter exposure times get you skipping (often wrongly called strobing), longer ones get you more motion blur than we're accustomed to from a century of watching films.

Shooting in interlace gets you at most about 65% of the resolution of progessive. It's limited in camera, because any more resolution that that and you'll have absolutely unwatchable interline flicker. Because things move between one field and the next, you also have to watch out for mouse teeth on the non-horizontal edges of moving objects.

On-set monitors can do more harm than good if they don't show you what you'll see in post. In many ways, we were better off in the pre video tap days.

Bottom line, shooting interlace when you want progressive is a bad idea. At best, it's a clumsy substitute for a diffusion filter.




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#9 David Mullen ASC

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Posted 02 May 2009 - 07:33 PM

That's ridiculous. Deinterlacing to 25P from 50i has no improvement on the movement -- you just have whatever the exposure time was per field, which you could select when shooting 25P and get the same motion results but twice the vertical resolution.

Getting subpar footage just because she doesn't like to look at 25P on the set monitor is silly.

Just shoot a test of 25P and of 50i converted to 25P, using the same shutter speed (1/50th probably), and show her the end results... and if they look the same or the 25P looks better, then this whole issue is just about her being annoyed with how 25P look on the monitor on the set and not about results.
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#10 Morgan Peline

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Posted 02 May 2009 - 10:40 PM

That's ridiculous. Deinterlacing to 25P from 50i has no improvement on the movement -- you just have whatever the exposure time was per field, which you could select when shooting 25P and get the same motion results but twice the vertical resolution.

Getting subpar footage just because she doesn't like to look at 25P on the set monitor is silly.

Just shoot a test of 25P and of 50i converted to 25P, using the same shutter speed (1/50th probably), and show her the end results... and if they look the same or the 25P looks better, then this whole issue is just about her being annoyed with how 25P look on the monitor on the set and not about results.



In that case, to get the the best option, the best setting is 1080/25p(over 50i) as we are shooting in Sinpapore which is a PAL country.

Thank you all for the info!
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#11 Thomas James

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Posted 03 May 2009 - 01:02 AM

Why don't you just shoot 720p at 50 frames per second and then you won't have to deinterlace.
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