Color Shifting / Pulsing at DVinfo.net

Matt Sturns · September 27th, 2011, 08:58 AM

Hello,

The footage I have been getting from the EX3 has been pulsing going through different colors. It is very slight and sometimes very hard to see but its definitely there and driving me crazy. Does anyone know why this is happening? Thanks

Alister Chapman · September 27th, 2011, 09:01 AM

Florescent lights is the most likely culprit. As the phase of the lamps changes with the pause of the shutter then the lighting will appear to change colour and flicker.

It's particularly bad if you are shooting at 24p or 24fps in a country where the mains is 60hz or 30fps in a country with 50hz mains.

Matt Sturns · September 27th, 2011, 10:54 AM

Thanks Alister you for the reply. Definitely not caused by fluorescents as the footage is outside under natural lighting (ie sun), also indoor with only tungsten lights (arri kit). Keeps going to a weird dull color, dull nasty green especially. And it is hard to see you really have to look for it but when you see it I can't see past it. Also always seems to be worse in background than foreground but can be anywhere. Also shooting 1080/30fps if this helps. Any other ideas? Thanks

Alister Chapman · September 27th, 2011, 11:15 AM

Have you got flicker reduction turned on? It can induce flicker. Are you certain its actually in the footage and not an edit suite or computer monitor issue? Beyond that I'm at a loss, other than possibly a fault.

Luc De Wandel · September 27th, 2011, 02:32 PM

If it's not fluorescent lighting, it could be moiré. I'd try to look at it on another monitor or a different resolution.

Matt Sturns · September 27th, 2011, 11:39 PM

Flicker reduction is turned off and still produces this phenomena (although it does not seem to be as frequent). I have tried viewing on several different monitors and viewing on a HDTV and monitor (via MXO2). Still pulsing effect. Any suggestions? I will try posting some footage soon... Thanks

Vincent Oliver · September 28th, 2011, 03:35 AM

What shutter speed and frame rate are you shooting at?

It could be that the frame rate is clashing with your monitor refresh rate (I presume this will be 60Hz)

Justin Molush · September 28th, 2011, 06:15 AM

I highly doubt this is the case given the EX3 is a good cam, but it couldn't be the AWB swinging around on you?

Do you see it on the cam's screen?

Matt Sturns · September 28th, 2011, 10:19 AM

Thank you for your replies. To answer some questions the footage was shot at 1080HQ / 30fps. I have viewed the footage on 2 different monitors, and HDTV and a Macbook Pro and still the same. I did not see it on the monitor but it is hard to see even on a 50" HDTV so I am guessing I would be unable to see the effects on the small camera LCD anyway. My shutter on front of camera is set to off. Flicker reduce is off. In the cameras menu the Shutter Options say
Mode: Speed
Shutter Speed: 1/60
The camera was white balanced and set to "A" preset so no AWB or PRST.
I will try posting some footage but I am away from the files at the moment, but will post soon.
Any Suggestions?
Thanks

Vincent Oliver · September 28th, 2011, 11:22 AM

As a hunch I suspect you are seeing a rolling shutter effect. I had something similar when shooting s river boat with a long telephoto lens on my EX3 (300mm Nikkor) I didn't notice a change in colour, but did notice a pulsing effect, maybe the overall water colour hid the colour shift. I suspect it is footage that is out of sync with your shutter speed and CMOS scan. I haven't seen the pulsing effect on my footage for some time.

If it is not that, then I too am baffled. Do some more tests with varying shutter speeds.

September 27th, 2011, 08:58 AM	#1
Matt Sturns Regular Crew Join Date: Aug 2008 Location: Providence, RI Posts: 53	Color Shifting / Pulsing Hello, The footage I have been getting from the EX3 has been pulsing going through different colors. It is very slight and sometimes very hard to see but its definitely there and driving me crazy. Does anyone know why this is happening? Thanks

September 27th, 2011, 09:01 AM	#2
Alister Chapman Inner Circle Join Date: Dec 2005 Location: Bracknell, Berkshire, UK Posts: 4,957	Re: Color Shifting / Pulsing Florescent lights is the most likely culprit. As the phase of the lamps changes with the pause of the shutter then the lighting will appear to change colour and flicker. It's particularly bad if you are shooting at 24p or 24fps in a country where the mains is 60hz or 30fps in a country with 50hz mains. __________________ Alister Chapman, Film-Maker/Stormchaser http://www.xdcam-user.com/alisters-blog/ My XDCAM site and blog. http://www.hurricane-rig.com

September 27th, 2011, 10:54 AM	#3
Matt Sturns Regular Crew Join Date: Aug 2008 Location: Providence, RI Posts: 53	Re: Color Shifting / Pulsing Thanks Alister you for the reply. Definitely not caused by fluorescents as the footage is outside under natural lighting (ie sun), also indoor with only tungsten lights (arri kit). Keeps going to a weird dull color, dull nasty green especially. And it is hard to see you really have to look for it but when you see it I can't see past it. Also always seems to be worse in background than foreground but can be anywhere. Also shooting 1080/30fps if this helps. Any other ideas? Thanks

September 27th, 2011, 11:15 AM	#4
Alister Chapman Inner Circle Join Date: Dec 2005 Location: Bracknell, Berkshire, UK Posts: 4,957	Re: Color Shifting / Pulsing Have you got flicker reduction turned on? It can induce flicker. Are you certain its actually in the footage and not an edit suite or computer monitor issue? Beyond that I'm at a loss, other than possibly a fault. __________________ Alister Chapman, Film-Maker/Stormchaser http://www.xdcam-user.com/alisters-blog/ My XDCAM site and blog. http://www.hurricane-rig.com

September 27th, 2011, 02:32 PM	#5
Luc De Wandel Major Player Join Date: May 2008 Location: Knokke-Heist, Belgium Posts: 963	Re: Color Shifting / Pulsing If it's not fluorescent lighting, it could be moiré. I'd try to look at it on another monitor or a different resolution.

September 27th, 2011, 11:39 PM	#6
Matt Sturns Regular Crew Join Date: Aug 2008 Location: Providence, RI Posts: 53	Re: Color Shifting / Pulsing Flicker reduction is turned off and still produces this phenomena (although it does not seem to be as frequent). I have tried viewing on several different monitors and viewing on a HDTV and monitor (via MXO2). Still pulsing effect. Any suggestions? I will try posting some footage soon... Thanks

September 28th, 2011, 03:35 AM	#7
Vincent Oliver Trustee Join Date: Sep 2004 Location: Chislehurst, London Posts: 1,724	Re: Color Shifting / Pulsing What shutter speed and frame rate are you shooting at? It could be that the frame rate is clashing with your monitor refresh rate (I presume this will be 60Hz) __________________ Eyes are a deaf man’s ears. Ears are a blind man’s eyes

September 28th, 2011, 06:15 AM	#8
Justin Molush Major Player Join Date: Jul 2010 Location: Montreal Posts: 388	Re: Color Shifting / Pulsing I highly doubt this is the case given the EX3 is a good cam, but it couldn't be the AWB swinging around on you? Do you see it on the cam's screen?

September 28th, 2011, 10:19 AM	#9
Matt Sturns Regular Crew Join Date: Aug 2008 Location: Providence, RI Posts: 53	Re: Color Shifting / Pulsing Thank you for your replies. To answer some questions the footage was shot at 1080HQ / 30fps. I have viewed the footage on 2 different monitors, and HDTV and a Macbook Pro and still the same. I did not see it on the monitor but it is hard to see even on a 50" HDTV so I am guessing I would be unable to see the effects on the small camera LCD anyway. My shutter on front of camera is set to off. Flicker reduce is off. In the cameras menu the Shutter Options say Mode: Speed Shutter Speed: 1/60 The camera was white balanced and set to "A" preset so no AWB or PRST. I will try posting some footage but I am away from the files at the moment, but will post soon. Any Suggestions? Thanks

September 28th, 2011, 11:22 AM	#10
Vincent Oliver Trustee Join Date: Sep 2004 Location: Chislehurst, London Posts: 1,724	Re: Color Shifting / Pulsing As a hunch I suspect you are seeing a rolling shutter effect. I had something similar when shooting s river boat with a long telephoto lens on my EX3 (300mm Nikkor) I didn't notice a change in colour, but did notice a pulsing effect, maybe the overall water colour hid the colour shift. I suspect it is footage that is out of sync with your shutter speed and CMOS scan. I haven't seen the pulsing effect on my footage for some time. If it is not that, then I too am baffled. Do some more tests with varying shutter speeds. __________________ Eyes are a deaf man’s ears. Ears are a blind man’s eyes