shooting a tv screen at DVinfo.net

Dennis Turkmen · August 25th, 2003, 10:08 PM

I was wondering how I can go about getting rid of the lines that appear when I shoot a television screen. Do I need to play around with the settings on the camera or is there some type of filter that will correct the problem?

Thanks
DVGuru@aol.com

Ken Tanaka · August 25th, 2003, 11:10 PM

The solution depends on the camera you are using. The Canon GL2 and XL1S have a feature called "Clear Scan" which alters the shutter speed ever so slightly to enable you to compensate for the refresh rate of the monitor.

If your camera does not have such a feature you will have to adjust your shutter speed to come as close as possible to eliminating the monitor's rescan lines. You may also be able to adjust the monitor's refresh rate to further help.

Alex Knappenberger · August 25th, 2003, 11:36 PM

Yeah, the easiest solution is to just shoot a LCD monitor, but shooting a TV is easy, beacuse they have a 60hz refresh rate, so as long as your at 1/60 shutter, it will be fine. Same with computer monitors, most are like 72hz and above, but you can change the settings and take it down to 60hz, and shoot at 1/60, and it will be alright. You'll probably still get a little thin line though...

Rob Wilson · August 26th, 2003, 10:36 AM

Clear Scan still works best. Using a 60th shutter will work but almost always will result in the "line". It's there because the shutter on your cam and the refresh of the set are not sync'ed. So although you will still have a line, at least it won't be moving!

Andre De Clercq · August 26th, 2003, 10:48 AM

"getting rid of the lines..." normally there is only one line or a fraction of a line if you shoot NTSC at 1/60 and PAL at 1/50. "Clearscan" simulation is possible on allmost all cams having variable shutter setting (in AE mode). So e.g. with a VX2000 there is no problem to perfectly shoot a 75 Hz CRT computerscreen.

Jeff Donald · August 26th, 2003, 12:15 PM

If it's a TV screen, shoot at a shutter speed below 1/60 of a second. A speed of 1/30 or 1/15 of a second is fine. Speeds lower thana 1/15 of a second may be blurry.

Computer monitors (CRT) do best with clear scan.

Andre De Clercq · August 26th, 2003, 01:58 PM

For shooting TV and computer CRT screens with vx2000 (and most other cams) see http://www.bbctraining.co.uk/onlineCourse.asp?tID=5173&cat=2781 and go to "open guide 3"

Dennis Turkmen · August 26th, 2003, 04:38 PM

I'm using a sony dcr-trv30. I don't think I'm able to adjust the shutter speed on it.

Glenn Chan · August 26th, 2003, 06:50 PM

There's a color slow shutter (or super nightshot) for you to try for fun. I doubt it will turn out nicely though.

Ken Tanaka · August 26th, 2003, 08:00 PM

Dennis,
All video cameras that I've ever seen have adjustable shutter speeds. Some have a greater range of speeds than others.

Check your manual.

Andre De Clercq · August 27th, 2003, 02:53 AM

Indeed Dennis, TRV30 is maybe fully automatic, so the aperure can't be locked (aperture priority). You need an LCD screen or follow Jeff's suggestion, but keep in mind that apart from the motion blurr with slow shutter settings, you reduce the vertical resolution by 50%, and in addition to that, most CCD structures show some blooming (leakage effects) due to the longer integration times and the "dead" (or weak) pixels tend to show up in the dark area's (fixed pattern noise). If it concerns a TV screen and you have the chance that the "line" (at 1/60)is not moving up or down. you can try a number of times the rec button on and off untill the line is hidden in the vertical retrace part of yr pic,

August 25th, 2003, 10:08 PM	#1
Dennis Turkmen New Boot Join Date: Nov 2002 Posts: 13	shooting a tv screen I was wondering how I can go about getting rid of the lines that appear when I shoot a television screen. Do I need to play around with the settings on the camera or is there some type of filter that will correct the problem? Thanks DVGuru@aol.com

August 25th, 2003, 11:10 PM	#2
Ken Tanaka Retired DV Info Net Almunus Join Date: Dec 2001 Location: Chicago, IL Posts: 6,943	The solution depends on the camera you are using. The Canon GL2 and XL1S have a feature called "Clear Scan" which alters the shutter speed ever so slightly to enable you to compensate for the refresh rate of the monitor. If your camera does not have such a feature you will have to adjust your shutter speed to come as close as possible to eliminating the monitor's rescan lines. You may also be able to adjust the monitor's refresh rate to further help. __________________ Lady X Films: A lady with a boring wardrobe...and a global mission. Hey, you don't have enough stuff! Buy with confidence from our sponsors. Hand-picked as the best in the business...Really! See some of my work one frame at a time: www.KenTanaka.com

August 26th, 2003, 12:15 PM	#6
Jeff Donald Warden Join Date: Mar 2002 Location: Clearwater, FL Posts: 8,287	If it's a TV screen, shoot at a shutter speed below 1/60 of a second. A speed of 1/30 or 1/15 of a second is fine. Speeds lower thana 1/15 of a second may be blurry. Computer monitors (CRT) do best with clear scan. __________________ Jeff Donald Carpe Diem Search DVinfo.net for quick answers \| Where to Buy? From the best in the business: DVinfo.net sponsors

August 26th, 2003, 08:00 PM	#10
Ken Tanaka Retired DV Info Net Almunus Join Date: Dec 2001 Location: Chicago, IL Posts: 6,943	Dennis, All video cameras that I've ever seen have adjustable shutter speeds. Some have a greater range of speeds than others. Check your manual. __________________ Lady X Films: A lady with a boring wardrobe...and a global mission. Hey, you don't have enough stuff! Buy with confidence from our sponsors. Hand-picked as the best in the business...Really! See some of my work one frame at a time: www.KenTanaka.com

August 25th, 2003, 11:36 PM	#3
Alex Knappenberger High School Student Join Date: Apr 2003 Location: Canton, Ohio, USA Posts: 609	Yeah, the easiest solution is to just shoot a LCD monitor, but shooting a TV is easy, beacuse they have a 60hz refresh rate, so as long as your at 1/60 shutter, it will be fine. Same with computer monitors, most are like 72hz and above, but you can change the settings and take it down to 60hz, and shoot at 1/60, and it will be alright. You'll probably still get a little thin line though...

August 26th, 2003, 10:36 AM	#4
Rob Wilson Major Player Join Date: Dec 2002 Location: Flagstaff, AZ Posts: 473	Clear Scan still works best. Using a 60th shutter will work but almost always will result in the "line". It's there because the shutter on your cam and the refresh of the set are not sync'ed. So although you will still have a line, at least it won't be moving!

August 26th, 2003, 10:48 AM	#5
Andre De Clercq Major Player Join Date: Sep 2002 Location: Belgium Posts: 804	"getting rid of the lines..." normally there is only one line or a fraction of a line if you shoot NTSC at 1/60 and PAL at 1/50. "Clearscan" simulation is possible on allmost all cams having variable shutter setting (in AE mode). So e.g. with a VX2000 there is no problem to perfectly shoot a 75 Hz CRT computerscreen.

August 26th, 2003, 01:58 PM	#7
Andre De Clercq Major Player Join Date: Sep 2002 Location: Belgium Posts: 804	For shooting TV and computer CRT screens with vx2000 (and most other cams) see http://www.bbctraining.co.uk/onlineCourse.asp?tID=5173&cat=2781 and go to "open guide 3"

August 26th, 2003, 04:38 PM	#8
Dennis Turkmen New Boot Join Date: Nov 2002 Posts: 13	I'm using a sony dcr-trv30. I don't think I'm able to adjust the shutter speed on it.

August 26th, 2003, 06:50 PM	#9
Glenn Chan Inner Circle Join Date: Jun 2003 Location: Toronto, Canada Posts: 4,750	There's a color slow shutter (or super nightshot) for you to try for fun. I doubt it will turn out nicely though.

August 27th, 2003, 02:53 AM	#11
Andre De Clercq Major Player Join Date: Sep 2002 Location: Belgium Posts: 804	Indeed Dennis, TRV30 is maybe fully automatic, so the aperure can't be locked (aperture priority). You need an LCD screen or follow Jeff's suggestion, but keep in mind that apart from the motion blurr with slow shutter settings, you reduce the vertical resolution by 50%, and in addition to that, most CCD structures show some blooming (leakage effects) due to the longer integration times and the "dead" (or weak) pixels tend to show up in the dark area's (fixed pattern noise). If it concerns a TV screen and you have the chance that the "line" (at 1/60)is not moving up or down. you can try a number of times the rec button on and off untill the line is hidden in the vertical retrace part of yr pic,