Jump to content


Photo

IR contamination


  • Please log in to reply
7 replies to this topic

#1 F Bulgarelli

F Bulgarelli
  • Basic Members
  • PipPipPipPip
  • 409 posts
  • Cinematographer

Posted 29 September 2011 - 08:02 PM

Hello
Has anyone had serious issues with IR contamination using the Epic?
I did a music video and when we got into the color correction stage realized that we could not get enough color saturation out of the images
RED has been looking at the R3D's and seem to think that we had issues with IR
We are still trying to determine the cause and was curious to find out if anyone else had issues like that. Basically, the image looks desaturated and low con, looks like a Raw image (that 's why it slipped thru the cracks) when we got into color correction the timer had to crank up the saturation to 200% in order to get some saturation but not enough to get strong dolors, specially greens

any comments or advice are appreciated

thx
  • 0

#2 Adrian Sierkowski

Adrian Sierkowski
  • Sustaining Members
  • 7374 posts
  • Cinematographer
  • Los Angeles, Ca

Posted 29 September 2011 - 08:42 PM

Any chance you can post up some stills? Also, where you heavily ND'd, like at a 1.2 or so? If so It could be you had an ND in there w/o the IR cut needed. I can't think of any lighting instruments that'd've caused it, though off hand, but I'm not a 100% expert. I do know when the red first came out, the sensor did have IR issues in daylight with ND, as the chips are more sensitive to ND. IT caused everyone to go with hot mirror filters at first, and eventually Tiffen et al to bring out NDs with a built in IR cut.

As for recovering the information; I dunno, but if RED has the files, hopefully they'll pull something out of 'em.
  • 0

#3 Keith Walters

Keith Walters
  • Sustaining Members
  • 2252 posts
  • Other
  • Sydney Australia

Posted 29 September 2011 - 09:55 PM

Hello
Has anyone had serious issues with IR contamination using the Epic?
I did a music video and when we got into the color correction stage realized that we could not get enough color saturation out of the images
RED has been looking at the R3D's and seem to think that we had issues with IR
We are still trying to determine the cause and was curious to find out if anyone else had issues like that. Basically, the image looks desaturated and low con, looks like a Raw image (that 's why it slipped thru the cracks) when we got into color correction the timer had to crank up the saturation to 200% in order to get some saturation but not enough to get strong dolors, specially greens

any comments or advice are appreciated

thx


I don't see any reason the Epic would be any different.
This thread illustrates the basic problem: like the dyes in the test tubes, the Bayer colour filters are completely transparent to infrared, so it't basically the same as somebody shinging a white light onto the sensor from inside the lens.

You may be able to balance that out in Post, but you're not going to be left with many bits of dynamic range to work with
  • 0

#4 F Bulgarelli

F Bulgarelli
  • Basic Members
  • PipPipPipPip
  • 409 posts
  • Cinematographer

Posted 29 September 2011 - 10:02 PM

Thanks Adrian
I'm starting to think that that was the problem.
Regardless of what the answer is, I've been shooting RED for a while and never had a problem, maybe there was a funky filter combination that created the problem.
Here is a still
  • 0

#5 F Bulgarelli

F Bulgarelli
  • Basic Members
  • PipPipPipPip
  • 409 posts
  • Cinematographer

Posted 29 September 2011 - 10:18 PM

Thanks Keith

here is the still, I do think that was the problem.

Attached Images

  • still2.jpg

  • 0

#6 Adrian Sierkowski

Adrian Sierkowski
  • Sustaining Members
  • 7374 posts
  • Cinematographer
  • Los Angeles, Ca

Posted 30 September 2011 - 12:49 AM

Not totally unusable.... 'course might not match anything else you have:

(5 minutes in photoshop.)
  • 0

#7 F Bulgarelli

F Bulgarelli
  • Basic Members
  • PipPipPipPip
  • 409 posts
  • Cinematographer

Posted 30 September 2011 - 10:37 AM

yeah, that's about how far we were able to take it,
could not recover much green
  • 0

#8 John Sprung

John Sprung
  • Sustaining Members
  • 4635 posts
  • Other

Posted 30 September 2011 - 06:57 PM

The IR thing is endemic to all big single chip cameras. We got bit by it on an Alexa once.




-- J.S.
  • 0


The Slider

New Pro Video - New and Used Equipment

FJS International, LLC

Broadcast Solutions Inc

CineTape

Aerial Filmworks

Tai Audio

Abel Cine

rebotnix Technologies

Technodolly

Media Blackout - Custom Cables and AKS

Rig Wheels Passport

Paralinx LLC

Metropolis Post

Visual Products

Willys Widgets

Ritter Battery

Glidecam

Gamma Ray Digital Inc

CineLab

Wooden Camera

Tai Audio

Rig Wheels Passport

Visual Products

CineLab

Abel Cine

CineTape

Wooden Camera

Glidecam

Technodolly

The Slider

Media Blackout - Custom Cables and AKS

Willys Widgets

Metropolis Post

rebotnix Technologies

Broadcast Solutions Inc

New Pro Video - New and Used Equipment

Gamma Ray Digital Inc

Ritter Battery

FJS International, LLC

Paralinx LLC

Aerial Filmworks