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#1 Cristian T

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Posted 05 December 2008 - 08:21 AM

Hello everyone!
I don't know where to post this, hope that someone will help me!
I want to transfer digital to film. I own a HVX200 PAL version camera... I've read the "Recommended Settings for the Panasonic HVX200 and Transfer to Film" on the dv website and others as well and I'm a little confused about the resolution ...
I want to record in 1080/25p and then in "post" to crop the image to fit 720p resolution, because in this way I can make the "composition" better, I can stabilize the image digitally if nedeed, etc... doesn't matter, don't ask :D
I've read that 720p will lose about 15-20 % resolution, I understand that, but what exactlly this process is, do they enlarge the actual image (720p) to fit 35mm? How this image would look like on a 35mm film, I heared that many people shoot 720p for theatrical purpose and not 1080, even though they lose some resolution. What's the big difference between the two formats (1080 vs 720) when it's transferred to film?
I really want to shoot 1080 and then to crop the image, it's more comfortable for me, it's very important if you want to correct the actual composition, etc.. and I don't know if this method it's recommended... and the most important thing is I'm a totally newbie...
Thank you!
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#2 Scott Fritzshall

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Posted 05 December 2008 - 11:47 AM

1. Please change your forums name to your full first and last name, as per the rules.
2. The HVX doesn't really have a very high resolution to begin with; its sensors are 960x540, slightly offset spatially in order to upsample to 720p via pixel shift. Shooting at 1080p further upsamples that. So you'd be upsampling quite a bit, then downsampling, then printing to film. If you're concerned about resolution, you don't want your image to go through so much processing- the best thing in your case would probably be to just shoot at 720p and then do your filmout from that.

I want to record in 1080/25p and then in "post" to crop the image to fit 720p resolution, because in this way I can make the "composition" better, I can stabilize the image digitally if nedeed, etc... doesn't matter, don't ask

Why not just shoot it properly to begin with? And I have to ask, how are you able to afford a filmout if you're such a newbie? If you've actually got the money to do that, I would recommend that you save it and put it into practicing shooting more.

I've read that 720p will lose about 15-20 % resolution, I understand that, but what exactlly this process is, do they enlarge the actual image (720p) to fit 35mm? How this image would look like on a 35mm film, I heared that many people shoot 720p for theatrical purpose and not 1080, even though they lose some resolution. What's the big difference between the two formats (1080 vs 720) when it's transferred to film?

720p is 1280x720, 1080p is 1920x1080. That's it. So shooting a format with a higher resolution to start out with gives you more resolution at the end. 720p will look a bit softer on film or when projected than 1080p.
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#3 David Mullen ASC

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Posted 05 December 2008 - 11:58 AM

While you can certainly crop a 1080P image in post and create whatever final video master you want from that for a film-out (you could crop and then enlarge back to 1080P for example), you will lose quality / resolution compared to not cropping.

Since the HVX200 does not have a true 1080P or 720P sensor, it's debatable whether the 1080P mode or 720P mode is better or worse in terms of final resolution since either mode involves uprezzing. But I certainly would avoid cropping & enlarging (except in an emergency, and in small amounts) for any work destined to be shown on a large movie screen.

The transfer to film is not really an "enlargement" per se, it's a transfer of a digital file onto the film frame. That file is whatever you deliver to the film-out company, whether a 1080P tape master or a 720P tape master. They may convert it to a format that their film recorder prefers though.

Part of learning to be a filmmaker is to get the image close to being "correct" in framing and camera operating as possible while shooting, not to shoot crappily and fix it all in post. That should be a worse-case scenario, fixing a shot, not a standard operating procedure.

Technically a 1080P frame has about twice as many pixels as a 720P frame (2MP versus 1MP) but that doesn't mean much, not all cameras are the same and not all recordings are the same, so it doesn't mean that a 1080P image is necessarily twice as sharp as a 720P image when both are shot at the same frame rate. Especially when your camera doesn't even have a 1080P sensor in it.
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#4 Cristian T

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Posted 05 December 2008 - 03:34 PM

Thanks a lot for the answer... Really helpful

1. I will change the name right now... I´m sorry :)
2. I don´t want to enlarge the cropped image back to 1080 ... I just want to leave it to 720, that´s will be the final output... And you´re right, the ideal method would be to ¨get the image close to being "correct"¨ without cropping anything... Cropping it´s not such a bad idea anyway, if you have enough resolution, etc... A lot of people do it, in photography as well. I didn´t say I want to crop everything, or just to make the whole composition in post, just to use it when I need it... And all of us no matter how professional are can´t make always the perfect composition while shooting, etc... But that´s my opinion, maybe you can.... And who said I want to use ¨crop¨ to fix everything in post? These are bad interpretation.
Anyway, thanks a lot, I´ll remind your suggestions...

Cheers!
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#5 Scott Fritzshall

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Posted 05 December 2008 - 04:26 PM

Thanks a lot for the answer... Really helpful

1. I will change the name right now... I´m sorry :)
2. I don´t want to enlarge the cropped image back to 1080 ... I just want to leave it to 720, that´s will be the final output... And you´re right, the ideal method would be to ¨get the image close to being "correct"¨ without cropping anything... Cropping it´s not such a bad idea anyway, if you have enough resolution, etc... A lot of people do it, in photography as well. I didn´t say I want to crop everything, or just to make the whole composition in post, just to use it when I need it... And all of us no matter how professional are can´t make always the perfect composition while shooting, etc... But that´s my opinion, maybe you can.... And who said I want to use ¨crop¨ to fix everything in post? These are bad interpretation.
Anyway, thanks a lot, I´ll remind your suggestions...

Cheers!

Well, it's true that cropping isn't bad if you have enough resolution... but that's a big "if." And in your case, you really don't have enough resolution to do very much without hurting image quality. In general you can only zoom in a few percent before it starts to look really bad, especially because you're blowing up the grain/noise along with the picture, and that's not only ugly, but it intercuts poorly with non-zoomed footage. In general, it's the job of the DP to get the shot correct. The only time you should be shooting with intent to reposition in post is when you've got a good reason planned out ahead of time. Yes, it's good to know that you have a bit of latitude to change things afterwards, and it's true that some shifting of framing sometimes takes place in order to cut better, but I really strongly urge you to shoot it correctly in the first place. The issue isn't that we can't always be perfect, the issue is that you really do need to learn how to compose properly to begin with.
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#6 David Mullen ASC

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Posted 05 December 2008 - 04:40 PM

Doesn't make much difference whether you crop 1080P to 720P and leave it 720P... or crop it to 720P and then uprez it back to 1080P. And I assume that, since what you deliver for film-out has to be one format, that you are planning on cropping everything to 720P (or shrinking some of it to 720P), not mixing 720P and 1080P in the same master.

Doesn't really matter one way or another, cropping is cropping, losing resolution, and when it's projected on a big screen, it will have less resolution than something that isn't cropped. How visible that loss will be is scene dependent. A close-up of a woman where you don't necessarily want to see every line and pore anyway... you can get away with more cropping than on a wide shot where you need to see more detail in the frame.

Also note that cropping will tend to enhance certain defects like noise, edge artifacts, etc. when it gets enlarged -- and it does get enlarged no matter how you think about it. Even if you crop 1080P to 720P's worth of pixels, if you compare the cropped image to the uncropped image on the same monitor, you are defacto "enlarging" the cropped image to fill the same sized monitor even if for the cropped image, you are sending a 720P signal instead of a 1080P signal. Cropping is cropping. There's no "cheat" around that unless the display format is much lower in resolution than the cropped image -- i.e. if everything ends up being shown 720P on a 720P monitor, or even smaller, as 480P on a 480P monitor.

But you're talking about a film-out, and also possible display on 1080P systems.

Again, crop when you have no other choice in order to make something work. Or you are dealing with conversions to different aspect ratios (like framing 16x9 HD for transfer to 2.40 anamorphic 35mm.)
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