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Red shoots red sometimes?


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#1 Bruce Greene

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Posted 10 February 2011 - 05:44 PM

I'm currently grading a feature shot with the Red MX.

Out of about 300 camera set-ups, 3 set-ups appear as if a red filter were placed in front of the lens. That's about 1% of the shots.

I don't think any menu items were changed, and I don't recall seeing this red color on the monitor when we shot it.

Anyone else had this experience and what might cause it?

I've tried going back to the RAW converter and these shots appear very red there as well. It's not a color temperature setting.

Thanks!
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#2 Adrian Sierkowski

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Posted 10 February 2011 - 09:11 PM

Were you behind any ND filters?
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#3 Bruce Greene

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Posted 11 February 2011 - 03:06 AM

Were you behind any ND filters?


One shot had ND filter, but the others in the same sequence look fine. The other shot was a night exterior with no filters. Again, one shot is red, but the next looks normal.

A colorist friend suggested it was a pola filter, but when I saw the night exterior, I knew it wasn't that.

Strange.
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#4 David Mullen ASC

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Posted 11 February 2011 - 03:20 AM

One shot had ND filter, but the others in the same sequence look fine. The other shot was a night exterior with no filters. Again, one shot is red, but the next looks normal.

A colorist friend suggested it was a pola filter, but when I saw the night exterior, I knew it wasn't that.

Strange.


Sounds like a processing / transcoding error of some sort, I doubt the RAW file is red (of course, a RAW file isn't any sort of color at all, but I doubt it only contains red information.) I'd send an R3D frame to the Red people and see if they can tell why it's converting incorrectly.
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#5 Bruce Greene

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Posted 11 February 2011 - 11:24 AM

Sounds like a processing / transcoding error of some sort, I doubt the RAW file is red (of course, a RAW file isn't any sort of color at all, but I doubt it only contains red information.) I'd send an R3D frame to the Red people and see if they can tell why it's converting incorrectly.


The files contain more than just red information and are correctable, but I don't think fully so. It takes a bit to make them match the other shots in the sequence. One shot is impossible to make look really good, but it's a little under-exposed in parts. I am correcting from the original .r3d files.

Thanks David for your advice to send the file to RED. I hadn't thought of that :unsure:

Can one send one frame of .r3d? Or do I need to seen the whole clip when it's in Red RAW format? I ask because I don't want to buy a hard drive to send it to them <_<
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#6 K Borowski

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Posted 11 February 2011 - 01:30 PM

That sounds like IR contamination.


I love puns and humor, but I really think, instead of an explanation poking fun at the problem, you really ought just post a frame instead. . .
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#7 Bruce Greene

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Posted 11 February 2011 - 04:19 PM

That sounds like IR contamination.


I love puns and humor, but I really think, instead of an explanation poking fun at the problem, you really ought just post a frame instead. . .


It's not IR in a night exterior shot without filtration when one angle is good and the other is red.

I would post a frame, but the data is on someone else's system and it's not easy for me to grab a frame...sorry.

And no puns were intended, at least by me. I'm not poking any fun at this problem, but if you can make me smile, go for it!
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#8 Adrian Sierkowski

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Posted 11 February 2011 - 04:21 PM

Just out of curiosity, it wasn't inordinately cold or hot out on set or on the body? I have noticed with some other CMOS systems cold/heat can have "visible" effects on some shots? just a though, of course.
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#9 John Sprung

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Posted 11 February 2011 - 05:30 PM

Is this red color shift absolutely even over the entire frame, or not? Red's OLPF is farther from the image plane than many other cameras, so scattering from it covers a wider area. I've seen a redness to the light that bounces around from a point source. So, it could be a complex interaction between a hot point source in or just out of frame, the lens, and the OLPF.





-- J.S.
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#10 Bruce Greene

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Posted 11 February 2011 - 07:13 PM

Is this red color shift absolutely even over the entire frame, or not? Red's OLPF is farther from the image plane than many other cameras, so scattering from it covers a wider area. I've seen a redness to the light that bounces around from a point source. So, it could be a complex interaction between a hot point source in or just out of frame, the lens, and the OLPF.

-- J.S.


The color shift is even over the entire frame. I'm virtually certain that it's not the OLPF.

But upon thinking about it, the problem takes were all taken on the same two days...don't know what that implies because it comes and goes.
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#11 Markus Rave

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Posted 12 February 2011 - 08:00 AM

I encountered color malfunctions on a feature last year. It turned out, the card reader was not working properly and since that could happen it might even be the card itself has problems. Check with Red. They are very helpful in every aspect and we had a new card reader very fast only paying for the shipment.
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