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Correct for barrel distortion in telecine?


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#1 Steve Zimmerman

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Posted 03 September 2007 - 04:26 AM

I am testing for an upcoming low budget short. no plans for film-out, just video projection.
I have a 35mm anamorphic lens and it has a good amount of barrel distortion just like the picture below. I was wondering if it was possible to correct for lens distortion in the telecine suite, zooming in and cropping the excess.

I fixed this shot below from The Untouchables in photoshop.

I love lens distortions at times, but I like flat field wide angle shots too. It kind of depends on the mood of the scene. Is this possible without losing video resolution by zooming in on the fine grained film image, NOT a video image in post, or do I have to do an expensive Digital Intermediate?

Thanks

Steve Zimmerman

Edited by Steve Zimmerman, 03 September 2007 - 04:29 AM.

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#2 Phil Rhodes

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Posted 03 September 2007 - 05:35 AM

Not as far as I'm aware. Best you can do is scan it at some resolution higher than your target and do it on that.

Phil
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#3 Stephen Williams

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Posted 03 September 2007 - 05:46 AM

Hi,

On an Rank telecine with tube, you probably could do it, weather the facility would want to is another matter.

Stephen
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#4 Steve Zimmerman

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Posted 03 September 2007 - 11:27 AM

Thanks for the replies guys. :) I figured that I'd need to transfer in High Def and do it in post. --But I'll ask at the transfer house as well.
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#5 David Mullen ASC

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Posted 03 September 2007 - 12:17 PM

If you want a flat field for wide-angle shots in a telecine/D.I. environment, shoot Super-35 with spherical lenses. I think to some extent, you have to embrace the quirks of anamorphic lenses if you are going to use them.
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#6 Scott Fritzshall

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Posted 03 September 2007 - 06:13 PM

There's no way to truly do it in Telecine. You'd need to shoot grid charts for each lens (which is time consuming and very boring) and then each shot basically becomes a visual effects shot, as you need to undistort each image using calculated distortion values based on the focal length and focus distance of each shot. The only off-the-shelf software that I'm aware of that has a model to remove anamorphic lens distortion is Monet, but I haven't used that feature of it yet so I can't tell you how good it is. I'd imagine it's kinda ok, but not great, especially if you're dealing with older anamorphics. Aside from that, you'd need to engage a pretty high-level VFX facility that has developed their own tools for it. Also, if you do manage to get it done, it will come at the consequence of softening your image pretty significantly.

Edited by Scott Fritzshall, 03 September 2007 - 06:14 PM.

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#7 Jon Kukla

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Posted 04 September 2007 - 01:58 AM

I agree with David - it seems that you're bending over backwards to get a rectilinear shot from a format that isn't really optimized for that. Is there a reason why you need to shoot in anamorphic instead of Super 35?
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#8 Steve Zimmerman

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Posted 04 September 2007 - 12:28 PM

Thanks for the responses.

Part of the reasoning behind the question was basic curiosity about what was possible.

I want to shoot anamorphic because it is the highest quality I can get with the cameras I have access to with the least money spent in post in case I do have a release print made. I also love the 2.4:1 format, asymetrical compositions, the unique bokeh, the smearing of the out of focus areas, 40% more negative area vs. S35, etc. --And to do something unique to stand out. S35 always looks like a cropped image to me.

I guess If I really do want everything to be squared off I guess I should just shoot Super 35 for those individual shots. That should work fine since my final output at this point would probably just be HD video anyway. It was interesting how Sunshine was shot as a combination of Anamorphic and S35, too bad I missed it at the theaters.
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#9 Chris Keth

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Posted 04 September 2007 - 05:47 PM

It's certainly possible. It's not at all practical unless you have a REALLY good reason to do it and can convince production of the need.
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#10 Jon Kukla

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Posted 04 September 2007 - 07:02 PM

Thanks for the responses.

Part of the reasoning behind the question was basic curiosity about what was possible.

I want to shoot anamorphic because it is the highest quality I can get with the cameras I have access to with the least money spent in post in case I do have a release print made. I also love the 2.4:1 format, asymetrical compositions, the unique bokeh, the smearing of the out of focus areas, 40% more negative area vs. S35, etc. --And to do something unique to stand out. S35 always looks like a cropped image to me.


The problem is that if you want to do correction to your distorted shots, you're gonna lose all that highest quality in the correction process and it will preclude you from creating a chain of contact prints. So you'd have to DI at least those shots anyway. Right?
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#11 Jon Kukla

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Posted 04 September 2007 - 07:07 PM

Also regarding Sunshine - they shot everything in anamorphic that didn't involve the sun, bc they didn't want it to give a horizontal flare. But since the film was all going to DI anyway, that probably wasn't as much of a problem.
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