How do you read IRE levels in Canon XH A1? at DVinfo.net

Kareem Dimashkie · February 27th, 2009, 11:38 AM

Hi everyone,

I am shooting on a green screen, and I was advised to set the green screen's IRE level in the camera to 50. How can the XHA1 allow me to see what IRE level the green screen is at?

Thanks,
Kareem Dimashkie

Brian Pratt · February 27th, 2009, 12:38 PM

Can't help you on IRE levels but some good help info here

General Specialist: Greenscreen and Bluescreen Checklist

Petri Kaipiainen · February 28th, 2009, 06:18 AM

I do not think you can check the levels on camera, you need vectorscope for that. Or something like DVRack or Canon Console which I use for greenscreen checking (level thin line at 50 IRE means flat even light).

One workaround is to have editor handy: shoot the backgound on tape and capture (or capture straight to HDD if possible), and use the scopes in the editor. Better than nothing.

One method would be to use zebra, set zebra level as low as possible and overexpose a bit, this would show the evennes of the light. Simple calculations could also give you the 50% level: zebra at 75% and one f-stop overexposure should give zebras at 50%.

Hope these ideas help.

Don Palomaki · February 28th, 2009, 08:15 AM

You can approximate IRE metering for a uniformly lit flat field object, such as a green screen in manual exposure mode using the meter scale in the upper left corner.

The triangle in the top center of the scale corresponds to approximately 50 IRE, and the scale divisions are in about 10 IRE steps. If you adjust the exposure so the exposure indicator marker that slides below the scale is in the center under the triangle the brightness is about 50 IRE.

February 27th, 2009, 11:38 AM	#1
Kareem Dimashkie Regular Crew Join Date: Aug 2008 Location: Encino, California Posts: 56	How do you read IRE levels in Canon XH A1? Hi everyone, I am shooting on a green screen, and I was advised to set the green screen's IRE level in the camera to 50. How can the XHA1 allow me to see what IRE level the green screen is at? Thanks, Kareem Dimashkie

February 28th, 2009, 08:15 AM	#4
Don Palomaki Wrangler Join Date: Sep 2001 Location: Northern VA Posts: 4,488	You can approximate IRE metering for a uniformly lit flat field object, such as a green screen in manual exposure mode using the meter scale in the upper left corner. The triangle in the top center of the scale corresponds to approximately 50 IRE, and the scale divisions are in about 10 IRE steps. If you adjust the exposure so the exposure indicator marker that slides below the scale is in the center under the triangle the brightness is about 50 IRE. __________________ dpalomaki@dspalomaki.com

February 27th, 2009, 12:38 PM	#2
Brian Pratt Regular Crew Join Date: Oct 2008 Location: Lancs, England Posts: 48	Can't help you on IRE levels but some good help info here General Specialist: Greenscreen and Bluescreen Checklist

February 28th, 2009, 06:18 AM	#3
Petri Kaipiainen Major Player Join Date: Apr 2007 Location: Espoo Finland Posts: 380	I do not think you can check the levels on camera, you need vectorscope for that. Or something like DVRack or Canon Console which I use for greenscreen checking (level thin line at 50 IRE means flat even light). One workaround is to have editor handy: shoot the backgound on tape and capture (or capture straight to HDD if possible), and use the scopes in the editor. Better than nothing. One method would be to use zebra, set zebra level as low as possible and overexpose a bit, this would show the evennes of the light. Simple calculations could also give you the 50% level: zebra at 75% and one f-stop overexposure should give zebras at 50%. Hope these ideas help.