brown lines across the screen at DVinfo.net

Claudio Paroli · September 10th, 2012, 06:24 PM

Hi, hope someone can help...
I got two thick horizontal brown lines moving slowly down the screen in a tungsten lit indoor shoot (see http://tvi.com.au/downloads/lines.jpg). The lines weren't visible during the shoot. My XDCAM EX3 (in full manual mode) had given a strange white balance reading, much redder than expected, when preparing for the shoot. Twice. I went with it because I'd been wrong before in judging colour temperature.
Fixing them has been hell in post.
I tested the camera afterwards in all light conditions and all the settings I could think of and have been unable to reproduce the problem.
Any ideas as to what might have caused it?
Many thanks
Claudio

Allan Black · September 11th, 2012, 12:39 AM

Welcome to the forum Claudio. Was this some sort of interference? Were you running on battery or AC power?

If AC, and you see those lines again, try swapping to battery or change to another outlet, especially if it's an old house with very old wiring.
The earth might be stuffed.

Cheers.

Alister Chapman · September 12th, 2012, 10:27 AM

Most likely a fluorescent or other discharge light spilling into the scene somewhere.

John DuMontelle · September 13th, 2012, 10:15 AM

Add my vote to possible fluorescent light being the culprit.

The part about the odd white balance along with the lines are what lead me to agree with Alister's diagnosis.

Thomas Nibler · September 14th, 2012, 02:57 PM

I know that problem too! (even without fluorescent light!)
My theory is, that you used a fast shutterspeed; that way you get these brown lines as a result of an missmatch between the flicker-frequency of the lightsource (50hz in Europe, 60 in US) and the Shutter / CMOS-Rolling Shutter-problem. (That Part of the Image is "darker", in wich the light was flickering.... keep in mind that the cmos-sensor is not read completely at one time, but line after line; check this out: CMOS Rolling Shutter (about partial exposure) )
Also make shure you have set your camera to the correct region (PAL or NTSC) you are filming in.
Whenever i run into that problem, it helps to set Shutter:off or try to find the specific shutter speed that matches.

September 10th, 2012, 06:24 PM	#1
Claudio Paroli Tourist Join Date: Sep 2012 Location: Sydney Australia Posts: 1	brown lines across the screen Hi, hope someone can help... I got two thick horizontal brown lines moving slowly down the screen in a tungsten lit indoor shoot (see http://tvi.com.au/downloads/lines.jpg). The lines weren't visible during the shoot. My XDCAM EX3 (in full manual mode) had given a strange white balance reading, much redder than expected, when preparing for the shoot. Twice. I went with it because I'd been wrong before in judging colour temperature. Fixing them has been hell in post. I tested the camera afterwards in all light conditions and all the settings I could think of and have been unable to reproduce the problem. Any ideas as to what might have caused it? Many thanks Claudio

September 11th, 2012, 12:39 AM	#2
Allan Black Inner Circle Join Date: Sep 2006 Location: Sydney. Posts: 2,929	Re: brown lines across the screen Welcome to the forum Claudio. Was this some sort of interference? Were you running on battery or AC power? If AC, and you see those lines again, try swapping to battery or change to another outlet, especially if it's an old house with very old wiring. The earth might be stuffed. Cheers. __________________ Drink more tap water. On admission at Sydney hospitals more than 5% of day patients are de-hydrated.

September 12th, 2012, 10:27 AM	#3
Alister Chapman Inner Circle Join Date: Dec 2005 Location: Bracknell, Berkshire, UK Posts: 4,957	Re: brown lines across the screen Most likely a fluorescent or other discharge light spilling into the scene somewhere. __________________ Alister Chapman, Film-Maker/Stormchaser http://www.xdcam-user.com/alisters-blog/ My XDCAM site and blog. http://www.hurricane-rig.com

September 13th, 2012, 10:15 AM	#4
John DuMontelle Regular Crew Join Date: Dec 2005 Location: Miami, Florida USA Posts: 114	Re: brown lines across the screen Add my vote to possible fluorescent light being the culprit. The part about the odd white balance along with the lines are what lead me to agree with Alister's diagnosis. __________________ John DuMontelle - Freelance / Miami, Florida - USA http://www.latincamproductions.com/

September 14th, 2012, 02:57 PM	#5
Thomas Nibler Regular Crew Join Date: Jul 2010 Location: Germany Posts: 51	Re: brown lines across the screen I know that problem too! (even without fluorescent light!) My theory is, that you used a fast shutterspeed; that way you get these brown lines as a result of an missmatch between the flicker-frequency of the lightsource (50hz in Europe, 60 in US) and the Shutter / CMOS-Rolling Shutter-problem. (That Part of the Image is "darker", in wich the light was flickering.... keep in mind that the cmos-sensor is not read completely at one time, but line after line; check this out: CMOS Rolling Shutter (about partial exposure) ) Also make shure you have set your camera to the correct region (PAL or NTSC) you are filming in. Whenever i run into that problem, it helps to set Shutter:off or try to find the specific shutter speed that matches.