High Shutter Speed Problem: Brown Lines under Fluorescent Lamps at DVinfo.net

Ilias Papaioannou · June 21st, 2011, 10:03 AM

Hello,

I was playing with my camera and I tried to put the shutter speed above 1/120 and I saw some brownish lines: I uploaded the video on megaupload: MEGAUPLOAD - The leading online storage and file delivery service (The video is too compressed, so, low quality but only 10MB).
I was under some old fluorescent lamps. I didn't have this problem with shutter speeds under 1/100 or the problem wasn't noticeable. I tried different frame rates on PAL and NTSC, different Gamma and Martix but nothing. The color temperature was at 5600K. Also I don't have the problem with other light sources.

Any ideas?

Thank you
Ilias

Dave Sperling · June 21st, 2011, 04:31 PM

Looks to me like a fluorescent ballast frequency issue - it's not that there are brown lines - it's just that those are the parts of the frame scan when the fluorescent is giving off less light, so they look darker. The window areas are fine.
So as you have probably already figured out, the solution is to use a slower shutter that more closely matches the line frequency of the current. (probably 1/50th ?) If none of the standard shutter speeds work, Set the shutter to ECS and adjust the speed to minimize it.

Colin Rowe · June 21st, 2011, 04:42 PM

Spot on Dave

Ilias Papaioannou · June 22nd, 2011, 12:00 AM

Thank you Dave! I will try to see if it works with ECS. I wanted to do some slomo with twixtor on after effects so I wanted clean frames with high Shutter Speed. I will simply do it under another light source. It seems much easier.

-Ilias

June 21st, 2011, 10:03 AM	#1
Ilias Papaioannou New Boot Join Date: Sep 2010 Location: Greece Posts: 21	High Shutter Speed Problem: Brown Lines under Fluorescent Lamps Hello, I was playing with my camera and I tried to put the shutter speed above 1/120 and I saw some brownish lines: I uploaded the video on megaupload: MEGAUPLOAD - The leading online storage and file delivery service (The video is too compressed, so, low quality but only 10MB). I was under some old fluorescent lamps. I didn't have this problem with shutter speeds under 1/100 or the problem wasn't noticeable. I tried different frame rates on PAL and NTSC, different Gamma and Martix but nothing. The color temperature was at 5600K. Also I don't have the problem with other light sources. Any ideas? Thank you Ilias

June 21st, 2011, 04:31 PM	#2
Dave Sperling Major Player Join Date: Jan 2010 Location: Tinton Falls, NJ Posts: 780	Re: High Shutter Speed Problem: Brown Lines under Fluorescent Lamps Looks to me like a fluorescent ballast frequency issue - it's not that there are brown lines - it's just that those are the parts of the frame scan when the fluorescent is giving off less light, so they look darker. The window areas are fine. So as you have probably already figured out, the solution is to use a slower shutter that more closely matches the line frequency of the current. (probably 1/50th ?) If none of the standard shutter speeds work, Set the shutter to ECS and adjust the speed to minimize it.

June 21st, 2011, 04:42 PM	#3
Colin Rowe Major Player Join Date: Jan 2004 Location: Cornwall UK Posts: 793	Re: High Shutter Speed Problem: Brown Lines under Fluorescent Lamps Spot on Dave __________________ Colin

June 22nd, 2011, 12:00 AM	#4
Ilias Papaioannou New Boot Join Date: Sep 2010 Location: Greece Posts: 21	Re: High Shutter Speed Problem: Brown Lines under Fluorescent Lamps Thank you Dave! I will try to see if it works with ECS. I wanted to do some slomo with twixtor on after effects so I wanted clean frames with high Shutter Speed. I will simply do it under another light source. It seems much easier. -Ilias