1080/60i Footage image strobe in Europe at DVinfo.net

Blake Stilwell · June 24th, 2008, 06:32 PM

I'm working on a North American TV doc series, which covers luxurious high end products from around the world. We're using 3 Sony EX1 cameras for acquisition and 6 Avid Media Composer suites connected to a UNITY media engine in post.

Aside from the painful workflow to get footage into Avid, everything is working great and the footage is breath taking.

Our problem is that footage shot overseas comes out with a serious lighting flicker on it. Anything shot indoors under artificial light or outside at night is affected. One camera man tried shooting at 1080/50i, which solved the strobing, but more than doubles the import time with all the transcoding that needs to happen in order to edit in a 60i project. It also results in an ugly stutter in the footage from the 5 repeated frames per second.

I'm looking for an in camera setting that will correct this lighting flicker issue. We've tried stuff with flicker reduction on and off, but haven't had any concrete results. Has anyone else experienced this, or know a fix.

Rick L. Allen · June 24th, 2008, 06:41 PM

The pulsing comes from the frequency or cycles of the lights in different countries. Set the shutter speed to 1/50 to match the 50Hz of PAL countries and 1/60 to match the 60 Hz of NTSC countries.

Craig Hollenback · June 24th, 2008, 06:58 PM

Quote:

Originally Posted by Rick L. Allen

The pulsing comes from the frequency or cycles of the lights in different countries. Set the shutter speed to 1/50 to match the 50Hz of PAL countries and 1/60 to match the 60 Hz of NTSC countries.

I had a similar problem in the US while shooting in the PAL format under 60cps flouresent lighing. What was even worse was watching the footage here on a PAL monitor. The footage was actually fine, but it was the US viewers perception of the footage when played back due to not being used to watching the different frame rate. I am told that if you watch 50i for about 3 weeks, you loose the flicker perception. This may sound like a joke but it actually is true.

Any rate...shoot it at 1/50th as per Rick's accurate advice.
Best, Craig

Blake Stilwell · June 25th, 2008, 12:16 AM

My shooter tells me that while shooting in 60i mode, a 1/50 shutter speed is not available, so he's been shooting at 1/100, which seems to reduce the flicker in the image, but does not completely eliminate it.

From my limited experience shooting on this camera, I remember seeing an option in the menu to toggle between shutter speeds, and shutter angles. Can anyone shed some light on this avenue for a possible solution?

Alexander Kubalsky · June 25th, 2008, 01:03 AM

The camera man should be able to flick through the different shutter/angle or speeds displayed on the LCD while filming using the direct menu togglestick on the top of the camera. When Im faced with flicker from lights I just have the scene set up and scroll through the shutter speeds until the flicker disappears. For very static shopts with not much movement shutter off works well. In NTSC countries shutter off is 1/24th, for PAL its 1/25th I guess.

Ps, Angle a speed are just different names for same thing so 1/48 Shutter Speed is 180 degrees etc.

Sebastien Thomas · June 25th, 2008, 02:04 AM

Quote:

Originally Posted by Alexander Kubalsky

The camera man should be able to flick through the different shutter/angle or speeds displayed on the LCD while filming using the direct menu togglestick on the top of the camera. When Im faced with flicker from lights I just have the scene set up and scroll through the shutter speeds until the flicker disappears. For very static shopts with not much movement shutter off works well. In NTSC countries shutter off is 1/24th, for PAL its 1/25th I guess.

Ps, Angle a speed are just different names for same thing so 1/48 Shutter Speed is 180 degrees etc.

Can't remember the name, but I think you have another option in the menu. Set your shutter speed to 1/50, then activate the option by telling you are in a 60Hz country.
I'll check that tomorrow if you want.

(be carefull at what i'm saying. I drink too much yesterday and am a bit away today)

Alister Chapman · June 25th, 2008, 03:55 AM

you can't have a 50th shutter at 60i as the shutter would be open longer than a field duration. Best to use 100th.

Bob Grant · June 25th, 2008, 05:59 AM

There is a flicker reduction filter in the EX1. Haven't tried it for this problem but the Z1 has much the same filter and it worked a treat shooting 60i with our 50Hz lighting.
Around the same time I had quite a bit of footage shot for us in the USA with Z1s at 50i and no flicker problem.
On the other hand 24p under 50Hz lighting with a rolling shutter is an impossible problem. You don't get flicker, you get rolling bars. This could be what's happening with the EX1 in which case shutter speed might make little difference. Just remembered what could be the crucial difference, the Z1 is CCD.

Blake Stilwell · June 25th, 2008, 08:09 AM

"You don't get flicker, you get rolling bars."
- Bob Grant

This is a more accurate description of the problem we're having with the footage. It's not as dramatic as the solid bars you would see on a computer screen while shooting at a frame rate out of sync with the monitor's refresh rate. Its soft, wide, dark rolling bars, that create the strobe look on the video.

We used Z1U cameras on season 1 of this same series two years ago, and shot all over Europe with no problems at all with the footage. I think you're on to something with this CCD vs CMOS idea. The rolling shutter could be the root of the problem, but I really don't know enough about how it works.

Rajiv Attingal · June 25th, 2008, 08:52 AM

If you could switch your display frequency to 50hz/60hz how it would behave?

Or is it happening in prograssive mode also?

June 24th, 2008, 06:32 PM	#1
Blake Stilwell Tourist Join Date: May 2008 Location: Moncton Posts: 3	1080/60i Footage image strobe in Europe I'm working on a North American TV doc series, which covers luxurious high end products from around the world. We're using 3 Sony EX1 cameras for acquisition and 6 Avid Media Composer suites connected to a UNITY media engine in post. Aside from the painful workflow to get footage into Avid, everything is working great and the footage is breath taking. Our problem is that footage shot overseas comes out with a serious lighting flicker on it. Anything shot indoors under artificial light or outside at night is affected. One camera man tried shooting at 1080/50i, which solved the strobing, but more than doubles the import time with all the transcoding that needs to happen in order to edit in a 60i project. It also results in an ugly stutter in the footage from the 5 repeated frames per second. I'm looking for an in camera setting that will correct this lighting flicker issue. We've tried stuff with flicker reduction on and off, but haven't had any concrete results. Has anyone else experienced this, or know a fix.

June 24th, 2008, 06:41 PM	#2
Rick L. Allen Major Player Join Date: Dec 2007 Location: Fayetteville, NC Posts: 535	The pulsing comes from the frequency or cycles of the lights in different countries. Set the shutter speed to 1/50 to match the 50Hz of PAL countries and 1/60 to match the 60 Hz of NTSC countries. __________________ "The good thing about science is that it's true whether you believe it or not." Neil deGrasse Tyson https://www.nautilusproductions.com/

June 25th, 2008, 12:16 AM	#4
Blake Stilwell Tourist Join Date: May 2008 Location: Moncton Posts: 3	Shutter Speeds Vs Shutter Anlge My shooter tells me that while shooting in 60i mode, a 1/50 shutter speed is not available, so he's been shooting at 1/100, which seems to reduce the flicker in the image, but does not completely eliminate it. From my limited experience shooting on this camera, I remember seeing an option in the menu to toggle between shutter speeds, and shutter angles. Can anyone shed some light on this avenue for a possible solution?

June 25th, 2008, 03:55 AM	#7
Alister Chapman Inner Circle Join Date: Dec 2005 Location: Bracknell, Berkshire, UK Posts: 4,957	you can't have a 50th shutter at 60i as the shutter would be open longer than a field duration. Best to use 100th. __________________ Alister Chapman, Film-Maker/Stormchaser http://www.xdcam-user.com/alisters-blog/ My XDCAM site and blog. http://www.hurricane-rig.com

June 25th, 2008, 08:52 AM	#10
Rajiv Attingal Regular Crew Join Date: Dec 2006 Location: Kerala, India Posts: 95	Switch Display If you could switch your display frequency to 50hz/60hz how it would behave? Or is it happening in prograssive mode also?

June 25th, 2008, 01:03 AM	#5
Alexander Kubalsky Regular Crew Join Date: Jan 2008 Location: Japan Posts: 172	The camera man should be able to flick through the different shutter/angle or speeds displayed on the LCD while filming using the direct menu togglestick on the top of the camera. When Im faced with flicker from lights I just have the scene set up and scroll through the shutter speeds until the flicker disappears. For very static shopts with not much movement shutter off works well. In NTSC countries shutter off is 1/24th, for PAL its 1/25th I guess. Ps, Angle a speed are just different names for same thing so 1/48 Shutter Speed is 180 degrees etc.

June 25th, 2008, 05:59 AM	#8
Bob Grant Trustee Join Date: Nov 2005 Location: Sydney Australia Posts: 1,570	There is a flicker reduction filter in the EX1. Haven't tried it for this problem but the Z1 has much the same filter and it worked a treat shooting 60i with our 50Hz lighting. Around the same time I had quite a bit of footage shot for us in the USA with Z1s at 50i and no flicker problem. On the other hand 24p under 50Hz lighting with a rolling shutter is an impossible problem. You don't get flicker, you get rolling bars. This could be what's happening with the EX1 in which case shutter speed might make little difference. Just remembered what could be the crucial difference, the Z1 is CCD.

June 25th, 2008, 08:09 AM	#9
Blake Stilwell Tourist Join Date: May 2008 Location: Moncton Posts: 3	"You don't get flicker, you get rolling bars." - Bob Grant This is a more accurate description of the problem we're having with the footage. It's not as dramatic as the solid bars you would see on a computer screen while shooting at a frame rate out of sync with the monitor's refresh rate. Its soft, wide, dark rolling bars, that create the strobe look on the video. We used Z1U cameras on season 1 of this same series two years ago, and shot all over Europe with no problems at all with the footage. I think you're on to something with this CCD vs CMOS idea. The rolling shutter could be the root of the problem, but I really don't know enough about how it works.