EX1: global or rolling shutter? at DVinfo.net

Bill Edmunds · November 13th, 2007, 03:51 PM

This article (below) brings up some serious issues with the rolling shutters used by CMOS cameras. Does anyone know whether the EX1 uses a rolling shutter?

http://dvxuser.com/jason/CMOS-CCD/

Craig Seeman · November 13th, 2007, 04:33 PM

Juan Martinez of Sony said the electronics behind the CMOS chip scan it top to bottom rather than across eliminating any rolling shutter (maybe really minimizing it's likelihood). Apparently it's being done differently in the EX1 than in say the V1.

David Heath · November 13th, 2007, 04:34 PM

I think the EX does use a rolling shutter, but there is a great deal of variation between rolling shutter implementations on differing cameras. The article puts the principles well, but a lot depends (like any shutter) on the speed at which it operates - a handheld still camera may show bad camera shake at 1/12s, but little at 1/125s, for example, and the same principle holds true here. By and large, the speed will be proportional to price.

Hence, the issues may well be serious with some CMOS cameras, but don't seem to be with others - Red also uses a rolling shutter.

Christopher Barry · November 13th, 2007, 05:06 PM

Quote:

Originally Posted by Craig Seeman

Juan Martinez of Sony said the electronics behind the CMOS chip scan it top to bottom rather than across eliminating any rolling shutter (maybe really minimizing it's likelihood). Apparently it's being done differently in the EX1 than in say the V1.

Craig, can you expand this? Does this mean the EX1 CMOS scans a whole line at a time, or other method? If Sony is improving on a known issue with CMOS, rolling shutter, this is a good thing. Craig, thank you.

Craig Seeman · November 13th, 2007, 05:28 PM

I'd hate to misqoute him but he didn't even need to wait for the question. Some of his presentation was specifically addressed at some criticism they've been getting about the technology ranging from 4:2:0 to CMOS rolling shutter. He had a Power Point slide at may have been referring to the speed at which the AD converters moves through the lines compared to the CMOS gathering info.

Basically he said you shouldn't see any skewing.

Seeing would be believing though. One might consider shooting out the window of a high speed train as it passes trees.

Christopher Barry · November 13th, 2007, 06:40 PM

Thanks Craig. Questions and answers. Not long now, and the footage will start to flow...

Matt Jeppsen · December 29th, 2007, 10:49 PM

I shot a police car at a traffic stop tonight with the EX1, and noted the same strobe light rolling shutter issue that has been spotted in Red One footage.

http://www.freshdv.com/2007/12/xdcam...artifacts.html

Will post some rolling shutter skew tests soon.

Paul Joy · December 30th, 2007, 07:30 AM

Hi Matt.

I just posted in another thread http://dvinfo.net/conf/showthread.php?t=111217
that switching the shutter off seems to stop the effect (at least with flash guns). Could you not just turn off the shutter for that type of shot?

regards

Paul.

Matt Jeppsen · December 30th, 2007, 11:28 AM

Thank you for that heads up, Paul. I'll test that out with a DSLR flash. Hopefully I can find another traffic stop as well for comparison.

Matt Jeppsen · January 1st, 2008, 03:35 AM

I've tested the EX with a consumer still camera, and it still catches some of the flashes in all the modes with the shutter turned off. I updated my above-linked post on the topic with example framegrabs.

November 13th, 2007, 03:51 PM	#1
Bill Edmunds Major Player Join Date: Aug 2003 Location: Conway, NH Posts: 574	EX1: global or rolling shutter? This article (below) brings up some serious issues with the rolling shutters used by CMOS cameras. Does anyone know whether the EX1 uses a rolling shutter? http://dvxuser.com/jason/CMOS-CCD/

December 29th, 2007, 10:49 PM	#7
Matt Jeppsen Trustee Join Date: Nov 2004 Location: Fayetteville, AR Posts: 1,425	EX1 Rolling Shutter Strobe Artifact I shot a police car at a traffic stop tonight with the EX1, and noted the same strobe light rolling shutter issue that has been spotted in Red One footage. http://www.freshdv.com/2007/12/xdcam...artifacts.html Will post some rolling shutter skew tests soon.

December 30th, 2007, 07:30 AM	#8
Paul Joy Major Player Join Date: Mar 2007 Location: Norfolk, UK Posts: 627	Hi Matt. I just posted in another thread http://dvinfo.net/conf/showthread.php?t=111217 that switching the shutter off seems to stop the effect (at least with flash guns). Could you not just turn off the shutter for that type of shot? regards Paul. __________________ Blog: www.pauljoy.com Company: www.videotrader.co.uk

November 13th, 2007, 04:33 PM	#2
Craig Seeman Inner Circle Join Date: Feb 2004 Location: Brooklyn, NY, USA Posts: 3,841	Juan Martinez of Sony said the electronics behind the CMOS chip scan it top to bottom rather than across eliminating any rolling shutter (maybe really minimizing it's likelihood). Apparently it's being done differently in the EX1 than in say the V1.

November 13th, 2007, 04:34 PM	#3
David Heath Inner Circle Join Date: Jan 2006 Posts: 2,699	I think the EX does use a rolling shutter, but there is a great deal of variation between rolling shutter implementations on differing cameras. The article puts the principles well, but a lot depends (like any shutter) on the speed at which it operates - a handheld still camera may show bad camera shake at 1/12s, but little at 1/125s, for example, and the same principle holds true here. By and large, the speed will be proportional to price. Hence, the issues may well be serious with some CMOS cameras, but don't seem to be with others - Red also uses a rolling shutter.

November 13th, 2007, 05:28 PM	#5
Craig Seeman Inner Circle Join Date: Feb 2004 Location: Brooklyn, NY, USA Posts: 3,841	I'd hate to misqoute him but he didn't even need to wait for the question. Some of his presentation was specifically addressed at some criticism they've been getting about the technology ranging from 4:2:0 to CMOS rolling shutter. He had a Power Point slide at may have been referring to the speed at which the AD converters moves through the lines compared to the CMOS gathering info. Basically he said you shouldn't see any skewing. Seeing would be believing though. One might consider shooting out the window of a high speed train as it passes trees.

November 13th, 2007, 06:40 PM	#6
Christopher Barry Regular Crew Join Date: Jan 2007 Location: Australia Posts: 107	Thanks Craig. Questions and answers. Not long now, and the footage will start to flow...

December 30th, 2007, 11:28 AM	#9
Matt Jeppsen Trustee Join Date: Nov 2004 Location: Fayetteville, AR Posts: 1,425	Thank you for that heads up, Paul. I'll test that out with a DSLR flash. Hopefully I can find another traffic stop as well for comparison.

January 1st, 2008, 03:35 AM	#10
Matt Jeppsen Trustee Join Date: Nov 2004 Location: Fayetteville, AR Posts: 1,425	I've tested the EX with a consumer still camera, and it still catches some of the flashes in all the modes with the shutter turned off. I updated my above-linked post on the topic with example framegrabs.